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StudioTech Annoucer's Console 233 User's Manual

1. Figure 11 Talkback 1 function mode settings Two modes are available e Disabled In this mode the talkback 1 button is disabled The talkback 1 line level output and if configured talkback to intercom pin 2 function will never be active An exception is if the auxiliary relay is configured to follow the status of the talkback 1 button In this case the talkback 1 button will only control the relay Enabled In this mode the talkback 1 button will operate normally Whenever the button is active the line level output and if configured the talkback to inter com pin 2 function will be active Issue 1 September 2007 Page 23 Model 233 Announcer s Console Talkback 2 Button Function Switch SW3 6 configures the overall operation of the button associated with talkback 2 SW3 6 Talkback 2 Function Mode 012345678 Disabled unless assigned to relay Erste Figure 12 Talkback 2 function mode settings Two modes are available Disabled In this mode the talkback 2 button is disabled The talkback 2 line level output and if configured talkback to intercom pin 3 function will never be active An exception is if the auxiliary relay is configured to follow the status of the talkback 2 button In this case the talkback 2 button will only control the relay Enabled In this mode the talkback 2 button w
2. modes should be considered before a final selection is made If possible experi menting with both modes in a test environ ment might prove to be very helpful Relay Mode Switch SW4 5 and SW4 6 configure the operating mode of the auxiliary relay SW4 5 and SW4 6 Relay Control Mode Relay disabled 012345678 Follows main output status Follows talkback 1 button status oo monn Follows talkback 2 button status EEJ Oo oOo Figure 19 Auxiliary relay control mode settings Four modes are available e Relay disabled In this mode the relay is disabled and will never change state Follows main output status In this mode the relay will follow the state of the main output Specifically the relay will change state energize whenever the main out put is active Follows talkback 1 button status In this mode the relay will follow the state of the talkback 1 button Specifically the relay will change state energize whenever the button is active Follows talkback 2 button status In this mode the relay will follow the state of the talkback 2 button Specifically the relay will change energize state whenever the button is active Model 233 User Guide Studio Technologies Inc System Mode Switch SW4 8 is used to configure the overall
3. 40 dB mode the minimum output level for the control on the far left and the control in the center is 40 dB below maximum the outputs will never fully mute This ensures that any cue audio signals present on the selected Model 233 inputs will always be present on the headphone output In most on air broadcast applications this is the appropri ate setting When the full mute mode is selected and the level level mode is also selected mov ing the control on the far left or the control in the center to their fully counterclockwise positions will cause their associated chan nel to fully mute This is identical to how the sidetone control located on the far right always functions When the full mute mode is selected and the level balance mode is also selected turning the control configured for level to its fully counterclockwise position will cause both headphone channels to mute SW4 3 Headphone Output Minimum Level 40 dB 012345678 Full mute Figure 17 Headphone output minimum level settings Issue 1 September 2007 Page 26 Turning the control assigned to be the bal ance control to either its fully clockwise or fully counterclockwise position will cause the appropriate channel to mute Selecting the full mute mode may be appropriate for applications where mini mizing the chance of audio leakage is important T
4. This minimizes the im pact that the unit s power draw could have on a connected intercom line If no external source of 24 volt DC is connected then power will be drawn from the intercom line And of course no matter which source is providing power full operation of the inter com interface can take place Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console Pushbutton Labeling The three pushbutton switches used in the Model 233 were selected for several reasons Foremost was the fact that they are highly reliable using gold plated con tacts for long life in less than ideal environ ments A second reason was that applying customized labels to the button caps would be very simple The labels text printed on clear material are placed under the clear caps on the top of the buttons From the factory the left button is labeled COUGH the center button is labeled TALKBACK 1 and the right button is labeled TALKBACK 2 This was selected to be appropriate for many on air applica tions in English speaking locations But it s expected that these may need to be changed to meet the needs of specific applications As a head start for some applications a clear sheet with a number of commonly used button designations printed on it is included in the shipping carton These were created at the factory using a stan dard personal computer graphics program and laser printed onto 3M CG3300 trans
5. center detent position making the level of the left and right channels equal In an ideal installation the level control can also be set to its detent position and provide a comfortable headphone output level This will allow the user in response to their preference or a changing environment to adjust the level and balance controls as desired The detent positions will always remain as a useful reference point To achieve this condition the audio levels on the connected line inputs must be ad justed as required Spending a few extra minutes trimming the connected audio levels rather than just providing what ever happens to come up should prove worthwhile The result will be talent that is more relaxed and an overall production that works more smoothly As previously mentioned a level trim potentiometer is associated with each line input If the line Issue 1 September 2007 Page 32 inputs are utilized as Cue sources adjust ing the trim pots may be helpful in achiev ing the desired adjustment range of the level controls Refer to the Technical Notes section of this user guide for details Monaural Headphone Output Level Control Operation As previously discussed the headphone output can be set for monaural operation This option is specifically provided so that a headphone mix mode can be cre ated If this has been enabled the three front panel level controls are used as a cue source mixer Independent cue input
6. headers provide access to the circuitry associated with these functions P18 Pin 1 is connected to the common point of the Model 233 s circuitry Pin 2 is con nected to the circuitry associated with the talkback 1 button Pin 3 is connected to the circuitry associated with the talkback 2 button Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console P19 Pin 1 is connected to the common point of the Model 233 s circuitry Pin 2 is connect ed to the circuitry associated with the main output pushbutton Pin 3 is connected to Circuitry associated with the tally output The remote switch input circuits are active low with a 10 k ohm resistor connected to 5 volts acting as a pull up A combination of resistors and capacitors provide ESD protection The tally output is nominally 3 5 volts DC and is current limited to 12 milliamperes This output can directly drive LED indicators Using a series resistor in the range of 150 to 330 ohms is recom mended This will limit the current while still providing adequate LED light output Compressor Circuit In this section some general information about the Model 233 s compressor circuit will be provided As previously discussed the output of the microphone preamplifier Circuit is connected to a studio quality com pressor circuit The output of the compres sor is used by the talkback functions and if configured the main output In most case
7. is located on the Model 233 s main printed circuit board It provides access to and a means to power the three lamps Issue 1 September 2007 Page 42 Pin 1 of the header is connected to the common point of the Model 233 s circuitry which is also connected to one contact on all the lamps Pin 2 of the header is con nected to the other contact on the lamps Pin 3 is connected by means of a current limiting resistor to the external 24 volt DC source If lamps were obtained from Stu dio Technologies then adding a jumper from pin 2 to pin 3 is all that is required to get things going A standard 0 1 inch center jumper commonly used on elec tronic equipment is all that is required A 200 ohm 2 watt resistor is electronically in series between the external 24 volt DC input and pin 3 of the header When used with the lamps available from Studio Tech nologies the resistor limits the lamp cur rent to approximately 65 mA This lights the lamps to a moderate intensity If a different type of lamp is installed its power source should be connected to pins 1 common and 2 lamps of the header Remote Control Tally Connections Provision has been made on the Model 233 s printed circuit board assembly to allow external switches or contact closures to control the main output and talkback button functions In addition a DC tally output signal provides an indication of the status of the main output Two 3 position
8. adjustment of the headphone output Two of the controls adjust the levels of the externally connected sources The third control is used to set the level of the side tone function For flexibility the actual functioning of the two controls associated with the external sources is configurable For traditional on air sports applications they can be selected to the dual level control mode which provides independent control of the left and right channel volume For use with stereo cue signals or to support user pref erence the level balance mode can be selected In this mode one control adjusts the overall level of both the left and right channels while the other allows adjust ment of the left right level balance To help minimize the chance of broadcast cues being missed both level control modes can be configured so that a minimum headphone output level is maintained Alternately the headphone output can be set to fully mute when these controls are at their minimum position Model 233 User Guide Studio Technologies Inc A headphone control reverse mode is provided specifically for on air television applications where a headset with boom microphone is used The reverse mode ensures that no matter which headset orientation is used by the talent the two pots controlling the external sources will always work intuitively This will result in a comfortable work environment allowing the left control to impact the level t
9. channel Finally the cue source whose level is to be adjusted by the center control is assigned to the right channel During operation the user will create their desired cue mix using these two front panel controls There may also be cases where a monau ral single muff headset or headphone will be connected to the Model 233 s headphone output In this case the desired source must be routed only to the left channel This is because the 2 conductor plug that s typically associ ated with a mono headset or headphone Model 233 User Guide Studio Technologies Inc will connect only to the tip lead left chan nel of the headphone output Signals assigned to the right channel will not be heard by the user Headphone Output Mode Switch SW1 6 allows a monaural head phone output to be created This is accom plished by summing adding the selected left and right channel cue signals The combined signals are sent to both the left and right channel headphone output driver circuits The outputs of these circuits con nect by way of 51 ohm series protection resistors to the headphone output jack SW1 6 Headphone Output Mode sereo Mono sums L R Figure 7 Headphone output mode settings The headphone output monaural mode feature was specifically included so that a 3 channel headphone mixer mode can be created By enabling the mono mode the three front p
10. has pin 1 floating pin 2 high pin 3 low P10 Line input 1 pin 1 common pin 2 high pin 3 low P11 Line input 2 pin 1 common pin 2 high pin 3 low P12 Intercom interface pin 1 common pin 2 DC with channel 1 audio pin 3 channel 2 audio Follows back panel 3 pin female XLR pin assignment P14 Pushbutton backlighting pin 1 common pin 2 button lamps pin 3 current limited 24 volts from external 24 volt DC input P15 Auxiliary relay contact B pin 1 normally closed pin 2 common pin 3 normally open P16 Auxiliary relay contact A pin 1 normally closed pin 2 common pin 3 normally open P17 Internal power supply rails pin 1 common pin 2 12 Vdc pin 3 12 P18 Remote talkback switch connections pin 1 common pin 2 talkback button 1 pin 3 talkback button 2 P19 Remote main output tally output connections pin 1 common pin 2 main output button pin 3 tally output 3 5 volt DC 12 milliampere maximum Pushbutton Backlighting For special applications provision as been made to allow illumination backlighting of the three pushbutton switches This may prove useful for applications where adequate room lighting is not available It can also serve in custom Model 233 Issue 1 September 2007 Page 41 Model 233 Announcer s Console configurations Note that this is an ad vanced feature intended only to be implemented by a qualified technician From the outset several limi
11. have a nominal level of 12 dBV to 6 dBu Two trim poten tiometers located on the bottom of the Model 233 s enclosure allow signals over this wide nominal level range to be effec tively utilized Audio sources are connected to the line inputs by way of 3 pin female XLR type connectors which are located on the unit s back panel Prepare the mating connec tors males so that pin 2 is signal high or hot pin 3 is low or cold and pin 1 is shield If connecting a source in this manner results in hum or noise it s pos sible that removing the shield connection from pin 1 can eliminate the issue With an unbalanced source connect pin 2 to signal high or hot and both pins 1 and 3 to shield If connecting an unbalanced source in this manner results in hum or noise connect pin 2 to high or hot and pin 3 to shield leave pin 1 unterminated Intercom Interface The Model 233 s intercom interface is designed to directly connect with standard single and dual channel party line inter com lines The one or two audio signals provided by the intercom line can serve as audio sources for the headphone outputs Each signal can be individually assigned to the left channel the right channel or both the left and right channels The Model 233 can also be configured to send talkback audio to either or both of the Issue 1 September 2007 Page 15 Model 233 Announcer s Console intercom channels In addition the
12. increases the perceived level of the left channel and vice versa As you may have already guessed when selecting the reverse left right mode of op eration everything is reversed To be more specific when selected for reverse mode and the level level mode is also selected the control on the far left adjusts the headphone output s right channel output jack s ring lead while the control in the center adjusts the left channel When se lected to the reverse mode and the level balance mode is also selected turning the balance control in the counterclockwise direction increases the perceived level of the right channel and vice versa The reverse mode is provided specifically for cases where a headset s left and right earpieces are placed on a user s head in a reverse orientation This ensures that the SW4 2 Headphone Control Operation Normal 012345678 Ni Reverse left right Figure 16 Headphone control operation settings Issue 1 September 2007 Page 25 Model 233 Announcer s Console user is provided with a consistent and easy to use set of headphone level controls Minimum Level Mode Switch SW4 3 is used to configure the minimum headphone output level for the controls located on the far left and center This setting doesn t impact operation of the sidetone level control which is located on the far right In the
13. input switch mode power supply is included with each Model 233 It s far from an ideal solution leading to noise on the intercom line s audio channels when long cable runs are present But at least users will have an emergency power source if nothing else is available In conclusion users where the AC mains source is 220 240 volts should consider locating an alternate 24 volt DC power source Several options are available that could make the task simple It s expected that a more sophisticated medical grade switch mode power supply will have much better control of induced noise It s highly likely that using one of these supplies will provide good results As the Model 233 s current requirement is 90 milliamperes at 24 volts a typical medical grade power supply should be able to power multiple units Another solution would be to obtain two of the more commonly available 12 volt DC linear power supplies con necting their outputs in series to create a 24 volt DC source While not a glamor ous solution it is technically correct and should prove cost effective If this arrange ment is implemented remember that the Issue 1 September 2007 Page 38 center pin of the 2 1 x 5 5 mm coaxial jack is used for the positive connection Symptoms of Insufficient Power A core part of the Model 233 s internal Circuitry is a switch mode power supply that produces 48 volts 12 volts 5 volts and 12
14. is set to the production system mode the status of talkback 1 will not impact the main output Talkback 1 Button Modes e Push to talk If this mode is selected the function s associated with the talkback 1 button is normally off The function s will become active whenever the button is pressed and held Hybrid This mode is a combination of push to talk and alternate action If the button is pressed and held the function s associated with the talkback 1 button will become active until the button is released If the button is mo mentarily tapped the function s will change state Upon Model 233 power up talkback 1 will be in its off state Talkback 2 Button and LED Indicator The button on the right factory labeled TALKBACK 2 controls the function s associated with talkback 2 The manner in which the button functions depends on Issue 1 September 2007 Page 30 how it was configured An LED indicator green in color is located directly above the button It lights whenever talkback 2 is active If the talkback 2 function mode has been configured for disabled it will light only if the auxiliary relay has been assigned to follow the talkback 2 button If the Model 233 is selected to the on air system mode whenever talkback 2 is ac tive the main output will be placed in the muted state If the Model 233 is set to the production system mode the status of talk back 2 will not impact the main output Talkback Outpu
15. multiple Model 233 units can be directly connected together Using a simple Y or W cable this pas sive summing adding together or bridg ing of talkback signals allows one audio cable to serve as a master talkback path A side effect from using this passive sum ming technique is that signal attenuation will occur The audio quality won t suffer but an audio pad is created If two line level talkback outputs are connected to gether a signal attenuation of 6 dB can be expected Connecting three talkback out puts together will result in 9 5 dB of atten uation And four talkback outputs multed together will lead to 12 dB of attenuation In most cases this attenuation won t pose a problem Typically a device that receives the talkback signal such as an amplified loudspeaker will have an adjustable input sensitivity so this attenuation won t prove to be a problem Line Inputs The Model 233 allows two line level audio sources to be connected These sources Model 233 User Guide Studio Technologies Inc can be individually routed to the left chan nel right channel or both the left and right channel of the headphone outputs The inputs are balanced transformer coupled with a nominal impedance of 10 k ohms Capacitors in series with the transformer s input leads prevent a DC voltage present on a connected source from impacting performance The line inputs are compat ible with signals that
16. on the metal shell con nection of the mating connector To limit the chance of grounding interaction be tween the Model 233 and connected equip ment pin 1 on the main output s connector is isolated from any point in the Model 233 The fact that pin 1 floats will minimize the chance of hums noises or buzzes being present on the equipment connected to the main output Issue 1 September 2007 Page 14 Line Level Talkback Outputs The two line level talkback outputs are intended to be connected to control rooms production trailers or other loca tions where talent originated voice cues are required The outputs are transformer balanced with a nominal level of 4 dBu To enhance talkback audio quality a com pressor circuit controls the dynamic range of the signal coming from the microphone preamplifier For protection against accidental connec tion to cables that have DC power present the line level talkback outputs are capaci tor coupled In series with the talkback output leads are 300 ohm resistors mak ing the effective output impedance ap proximately 600 ohms These resistors create a passive summing network allow ing talkback outputs on multiple Model 233 units to be connected bridged together The line level talkback outputs are con nected by way of two 3 pin male XLR type connectors which are located on the Model 233 s back panel The mating connectors female should be prepared so th
17. operating mode of the Model 233 Understanding how the two modes impact overall system operation will ensure that correct operation and maximum usabil ity will occur When selected to the on air mode the main output will mute whenever a talkback function is active The LED indi cators associated with the main output will light accordingly The on air mode should be selected for all on air broadcast applica tions It s imperative that the main output be muted whenever on air talent is using one of the talkback functions to communi cate with production personnel When configured for the production mode the main output is never muted in response to a talkback function being active The main output will be controlled only by the main output pushbutton This mode allows the main output to be used for example as an additional talkback output In this way the main output and talkback out put functions can be used independently with neither impacting the other This also allows all three buttons to be used simul taneously Note that as is always the case the audio source for the main output is depending on its configuration either the output of the microphone preamplifier or the output of the compressor In summary when selected for the correct application both the system modes can prove equally effective A thorough study SW4 8 System Mode 912345678 On air talkback output status impacts main
18. operation The following paragraphs will describe how these controls will function in that scenario Level Level Mode When set to the level level mode the con trol on the far left and the control in the center operate independently Each control sets the output level of one channel of the headphone output If configured to the normal mode the control on the far left is used to adjust the level of the headphone output s left channel The control in the center is used to adjust the level of the right channel If configured to the reverse left right mode the control on the far left adjusts the headphone output s right chan nel The control in the center adjusts the left channel When in the level level mode and the mini mum output level is set for 40 dB turning each control to its fully counterclockwise position will place its respective output level 40 dB below its maximum This set ting ensures that talent will never be fully isolated from potentially important cue signals If present on one of the Model 233 s inputs and assigned to the head phone channels some audio signal will always be present on the headphone output If set to the full mute mode turning each control to its fully counterclockwise position will cause its respective output to fully mute The Model 233 s level controls have a mechanical step detent that is located at the halfway 50 position of their rota tion range This is intended
19. output status 912345678 Production talkback output status does not impact main output status Figure 20 System mode settings Issue 1 September 2007 Page 27 Model 233 Announcer s Console of how they impact the Model 233 s operation can lead to many interesting and powerful uses Talkback to Intercom Functions The last two switches in switch assembly SW2 are used to configure the talkback to intercom functions Talkback 1 to Intercom Function Mode Switch SW2 11 configures whether the talkback 1 button will allow talkback audio to be sent to pin 2 of the intercom interface SW2 11 Talkback 1 to Intercom Pin 2 123456789101112 7 8 9101112 lo t Figure 21 Talkback 1 to intercom pin 2 settings Two modes are available e Disabled In this mode the talkback 1 button will not allow talkback audio to be sent to pin 2 of the intercom interface e Talkback 1 to intercom interface pin 2 In this mode the talkback 1 button will control the routing of talkback audio to pin 2 of the intercom interface Pin 2 is channel 1 of an RTS intercom system Talkback 2 to Intercom Function Mode Switch SW3 12 configures whether the talkback 2 button will allow talkback audio to be sent to pin 3 of the intercom interface Two modes are available e Disabl
20. parency film The desired button labels can be cut out with a pair of scissors fol lowing the printed guide lines that indicate the required size The clear lens on top of each button cap can be removed with a fingernail or small screwdriver Be certain not to scratch the button if a screwdriver or other small tool is used The clear label can be removed and replaced The button cap is then snapped back into the top of the button housing using finger pressure only No tool is required to replace the button cap If you need to make your own labels the process is quite simple Use a personal Model 233 User Guide Studio Technologies Inc computer to create the desired text The finished label size should be 0 625 inches 15 8 mm square The completed artwork can then be printed on transparency film sheets using a laser or inkjet printer These sheets are readily available from most office supply stores A pair of scissors or an X ACTO knife will complete the task Configuration For the Model 233 to support the needs of specific applications a number of operating parameters must be configured These include microphone preamplifier gain phantom power on off headphone source and output mode selection and operating modes One 12 position and three 8 position DIP type switch assemblies are used to establish the desired configura tion These switch assemblies are referred to as SW1 through SW4 with individual switches desig
21. professional interface with high output capability low distortion and low noise Issue 1 September 2007 Page 6 The output circuitry features a high performance output transformer expressly designed for professional audio applications Talkback Functions The talkback functions are intended to provide personnel associated with production trucks control rooms live performance and sports venues with talent originated cue signals The Model 233 contains two pushbutton switches that control the talkback functions As sociated with each pushbutton switch is a dedicated line level talkback output Each pushbutton switch can also be configured to send audio to one specific channel associated with the Model 233 s dual channel intercom interface The line level talkback outputs are transformer coupled with a 4 dBu nominal signal level They contain resis tors in series with the output connectors allowing line level talkback outputs from multiple units to be directly summed For non on air applications a special Model 233 feature set can be enabled by placing the unit in its production mode This software based mode allows the Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console main output to be used as an additional talkback output This feature makes the unit even more powerful when used in live event applications such as serving as a master console for an orchestra con
22. to serve as an aid to Model 233 users In an ideal Model 233 User Guide Studio Technologies Inc installation setting the far left and center controls to their detent position will result in a comfortable headphone output level The user in response to a changing operating environment can then move the controls to get more or less level as desired The de tent position will always remain as a useful reference point To achieve this condition the audio level on the connected line inputs may have to be calibrated as required This is somewhat counter to the usual mental ity of just providing the user with whatever level comes up by default Spending a few extra minutes trimming the audio levels can result in much happier and more pro ductive talent As previously mentioned a level trim potentiometer is associated with each line input These may be helpful in achieving the desired adjustment range of these two level controls Refer to the Technical Notes section of this user guide for details Level Balance Mode When set to the level balance mode the control on the far left and the control in the center operate together to adjust the head phone output level The control on the far left adjusts the overall level of both the left and right channels The balance control located in the center adjusts the relative left right level balance In this mode the controls operate in a manner reminiscent of a consumer audio ampli
23. two LED indica tors are associated with the main output and are located directly above the main output pushbutton switch The red LED located on the left is lit whenever the main output is muted The green LED located on the right is lit whenever the main output is active The thought pro cess behind the color choices was that red would relate to the main output being muted stop while green would relate to the main output being active go It s possible that these color choices may not meet the needs of all users and applica tions For example it s reported that one European broadcaster typically uses these two colors in the opposite fashion Their choice is to have the red LED lit whenever the main output is active warning the tal ent that they are on air The green LED is lit whenever the main output is muted indicating to the talent that it s safe to say whatever they wish about whomever they wish to say it about For consistency the LED associated with each talkback button was selected to be green They light whenever their associ ated talkback output is active It s possible that some applications may benefit from revising these LED colors too While red is certainly one possible choice other col ors are also a possibility including amber orange or blue these days there are lots of choices available The only limitation is the amount of current available to light each LED Usin
24. 3 s operat ing modes Technically these switches talk to the microcontroller integrated circuit and associated software that give the Model 233 its smarts The software has been carefully designed to provide a number of different ways in which the unit can function It s critical to carefully review the available options and choose the ones that best meet the needs of a specific application Note that switches can be changed even while the Model 233 is powered up and operating The unit s operating characteristics will change in real time in response to configuration changes In addition to the switch assemblies SW3 and SW4 the last two positions of switch assembly SW2 are used for configuration Specifically SW2 11 and SW2 12 are used for the talkback to intercom functions Issue 1 September 2007 Page 22 Main Output Button Mode Switches SW3 1 and SW3 2 configure how the main output button functions SW3 1 and SW3 2 Main Button Mode 6 12345678 Push to mute cough 012345678 Push to talk Alternate action latching 9123456769 Hybrid press and hold to enable tap to latch Figure 8 Main output button mode settings There are four available modes e Push to mute In this mode the main output is normally active The ma
25. 33 Announcer s Console is designed to serve as the audio control hub for announcers commentators and production personnel The tabletop unit is suited for numerous applications includ ing on air television and radio broadcast ing The Model 233 will also perform an outstanding role in stadium announce applications The Model 233 is compatible with essentially all broadcast and produc tion audio system environments Standard connectors are used to interface micro phone headphone on air talkback line input and intercom signals Whether it s the mic preamplifier audio switching talkback signals intercom inter facing or headphone cue feed superior audio quality is maintained throughout A microprocessor provides the Model 233 s logic power allowing precise control of the unit s operation With extensive flexibil ity built in creating the desired operating configuration is a simple matter While the operating features of the unit can be care fully tailored the user is presented with an easy to use set of controls and indicators A wide range of resources great perfor mance and simplicity during use these are the hallmarks of the Model 233 The Model 233 is a truly next generation and then some product Exhaustive re search into the needs and desires of field production personnel was integral to its creation Providing a veritable tool kit of features the unit supports a wide variety of a
26. 600 ohms Nominal Level 4 dBu Maximum Level 11 dBu compressor restricts maximum Headphone Output 1 stereo Compatibility intended for connection to mono or stereo headphones or headsets with nominal impedance of 100 ohms or greater Type voltage driver Maximum Output Voltage 8 Vpp 150 ohm load Auxiliary Relay Function software configurable Contacts 2 form C Common Normally Closed Normally Open Rating 1 A 30 W resistive Access requires user implemented connector scheme Tally Output 3 5 Vdc 12 mA maximum nominal Power Sources Intercom Interface 24 32 Vdc 125 mA External 24 Vdc 90 mA 24 Vdc acceptable range 20 30 Vdc Units shipped to North America and Japan include a 120 V input 24 Vdc output power supply Units shipped to all other locations include a universal input 24 Vdc output power supply Dimensions Overall 8 1 inches wide 20 6 cm 3 3 inches high 8 4 cm 8 5 inches deep 22 4 cm Weight 4 5 pounds 2 1 kg Specifications and information contained in this User Guide subject to change without notice Model 233 User Guide Studio Technologies Inc Appendix A Model 233 Announcer s Console A label is attached to the security plate on the bottom of the unit It provides a summary of the configurable parameters and related information The actual label size 4 80 inches by 5 90 inches Assign to Left Headphone Pin 2 Pin 3 Intercom Pin 3 Intercom
27. ION OUTPUT DIP SWITCH 3 PIN HEADERS NC2 i AUXILIARY TALK TALK INTERCOM t 2 coma i TALK TO aaa RELAY VL MAIN Back 1 BACK 2 INTERFACE gt INTERCOM 2 OFF ON ON ON PIN 2 XLR F 4 FP sncroe HEADPHONE LEVEL 1 CONFIGURATION DIP SWITCH MICROCONTROLLER INTERCOM HEADPHONE amp LOGIC TALK TO INTERFACE LEVEL 2 PIN 3 SIDETONE LEVEL o MAN 555 TALKBACK 1 MAIN REMOTE MAIN INPUT Tatty TALLY OUTPUT CURRENT 3 PIN HEADER COM LIMITED be OUTPUT CONFIGURATION DIP SWITCHES DIGITAL TYPICAL OF 18 LEVEL TALKBACK 1 ae CONTROL REMOTE TB1 amp TALKBACK 2 2 INPUTS 3 PIN HEADER COM DIGITAL LEVEL CONTROL SUMMING VOLTAGE POWER BUFFER HEADPHONE SOURCE S BUFFER AMPLIFIER R 10K 10K LEFT LEVEL AW AW HEADPHONE OUTPUT CONTROL 1 4 INCH 3 COND LINE INPUT 1 oe MONO w XLR F 3 LEVEL ae 10 TO 4dBu TRIM 1 RIGHT BUFFER DIGITAL LEVEL 1 CONTROL 2 LINE INPUT 2 XLR Fe 3 LEVEL ae 10 TO 4dBu BE TRIM 4 48V POWER gt 12V suPPLY 24VDC INPUT 2 1 X 5 0MMs gt 12V w M233BD_A BUTTON BACKLIGHTING 3 PIN HEADER STUDIO TECHNOLOGIES INC MODEL 233 ANNOUNCER S CONSOLE BLOCK DIAGRAM DRAWING DATE PAGE ALSO HAS 3 PIN HEADER IN PARALLEL ON PRINTED CIRCUIT BOARD 31272 06 25 07 01 01
28. Model 233 Announcer s Console User Guide Issue 1 September 2007 This User Guide is applicable for serial numbers M233 00151 and later Copyright 2007 by Studio Technologies Inc all rights reserved www studio tech com 50336 0907 Issue 1 This page intentionally left blank Model 233 Announcer s Console Table of Contents 5 System Features deendauabiet eecotaes 6 Installation and 12 Configuratii ea te errr aaia 17 de lo a E A E 28 Advanced 33 Technical NOTES 94 45 ieai 46 Block Diagram Model 233 User Guide Issue 1 September 2007 Studio Technologies Inc Page 3 Model 233 Announcer s Console This page intentionally left blank Issue 1 September 2007 Model 233 User Guide Page 4 Studio Technologies Inc Model 233 Announcer s Console Introduction What This User Guide Covers This User Guide is designed to assist you when installing configuring and using the Model 233 Announcer s Console Ad ditional background technical information is also provided A product block diagram is included at the end of this guide System Overview The Model 2
29. Pin 2 Studio Technologies Inc Model 233 Configuration Settings For full documentation see www studio tech com Sidetone Line In 2 Line In 1 r 000o Hiini Intercom Sidetone Level Line In Level Trim Switch 2 Headphone Sources Talkback to Intercom Operating Modes Switch 3 Switch 4 012345678 Prp 012345678 erp Main Button H Talkback 1 Button Talkback 2 Button Talkback 1 Function Talkback 2 Function i System Mode Spare Relay Mode Main Button Mode Main Output Source Sidetone Mode Main Button Y Y Push to mute AY Push to talk Y A Latching A A Hybrid Talkback 1 2 Button Vv Push to talk A Hybrid Talkback 1 2 Function Y Disabled relay only A Enabled Main Output Source Mic preamplifier 4 Compressor Issue 1 September 2007 Page 45 Sidetone Mode Vv Main button A Main amp Talkback buttons Headphone Controls Vv Level level A Level balance Headphone Reverse Vv Normal A Reverse Main Button Mode Y Normal A Talkback forces latch off Relay Mode Vv V Disabled AY Main output Y A Talkback 1 A Talkback 2 System Mode Assign to Right Headphone r Line In 1 Line In 2 Intercom Pin 2 Intercom Pin 3 Sidetone RTS TW Channel 1 RTS TW Channel 2 or Clear Com Channel 1 Talkback 1 to Intercom Pin 2 Talkback 2 to Intercom Pin 3 Phantom Power 48 V Spare Headphone Stereo M
30. This mode would be appropriate for applica tions such as stadium announcement An alternate action latching configuration allows the button to enable or disable the main output as desired This is useful in Issue 1 September 2007 Page 7 Model 233 Announcer s Console radio broadcasting announce booth or voice over applications The fourth mode provides a hybrid function supporting both push to talk and tap to enable tap to disable operation This operation is similar to that found in many broadcast intercom system user stations The two buttons associated with the talk back functions can be configured to oper ate from either of two modes One of the modes supports a push to talk function This is typically used for on air broadcast applications The other mode provides a hybrid function the operation of which is discussed in the previous paragraph The hybrid mode is especially useful when the Model 233 is used in a production support application The main button mode configures how the main output when it is in the latched on state responds to talkback activity One choice momentarily turns off the main output when talkback is active returning the main output to the on state when the talkback function has ended The other choice unlatches the main output in response to a talkback function Cue Sources The Model 233 supports the connection of up to four external audio sources each of
31. ack panel is also intended to secure the replacement connectors If connectors are added to the Model 233 s spare connector locations adding labels to those connectors can be helpful For a great look it is recommended that Brother P Touch 4 inch 6 mm labels be created Tape material that prints white text on a black background works out well for the Model 233 The Brother label cassette number TX 3151 white on black is appropriate for use with many of their printers In addition to the spare connector loca tions on the back panel provision has been made to allow easy interconnection with the Model 233 s printed circuit board mounted input and output connectors This was accomplished by including numerous 3 position male header con nectors on the Model 233 s circuit board These headers on 0 1 inch centers are Issue 1 September 2007 Page 40 wired in parallel with the Model 233 s con nectors This no solder solution makes customizing a Model 233 a simple pro cess The headers located on the Model 233 s printed circuit board are Molex part number 22 23 2031 They mate with Molex housing number 22 01 3037 To make the interconnection separate crimp terminals are attached to loose wires and then snapped into the housing Molex part number 08 50 0114 specifies crimp terminals that are appropriate for wires of 22 to 30 gauge These parts are available worldwide from sources such as Digi Ke
32. age 36 Clear Com systems did use a nominal level of approximately 20 dB But after making controlled tests the contemporary Clear Com equipment seemed to be much closer to 10 dBu And with the limited dynamic range control that we experi enced the actual level during operation may vary widely That s why intercom interface sensitivity or compatibility switch es or rotary controls were not included in the Model 233 But just in case a change is ever required intercom interface gain levels are set using several 1 4 watt 1 tolerance resistors If necessary these can be changed by a qualified technician In conclusion the engineers at Studio Technologies are always open to learn ing more Additional information from the field concerning such topics as intercom system levels impedance matching and DC power sourcing would be welcomed Stopping by our offices for an in person chat would be also great Bringing along a bit of road swag would be appreciat ed Just park the production trailers in the alley behind our warehouse plenty of power is available Connecting an IFB Circuit A broadcast standard wet DC with au dio IFB circuit can be directly connected to the Model 233 s intercom input Origi nated by sources such as the RTS 4000 series IFB system or IFB interface devices from Studio Technologies the connected IFB circuit can provide two channels of cue audio as well as DC power to oper ate t
33. amplifier to be routed to the stereo headphone output This provides a confidence signal to the user allowing them to hear exactly what is being sent to the main and if desired talkback outputs This sidetone signal can be a critical element when creating an effective communications environment In on air television and radio broadcast settings the Model 233 user s own micro phone audio signal is typically returned to the headphone output by way of a cue audio source But there are cases where this signal is not available such as when mix minus cue feeds are utilized This type of cue feed includes everything but the user audio a requirement when sig nificant time delays typically associated Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console with satellite transmission systems are present In effect the Model 233 s sidetone function adds the minus part to a mix minus cue Several configurable parameters allow the sidetone function to be tailored to the needs of a specific Model 233 installation The sidetone function can be configured to route audio to the left right or left and right headphone outputs It can also be completely disabled Sidetone can also be configured to be active only when the main output is active or to be active anytime the main output or either of the talkback outputs is active Headphone Output Three rotary controls are provided for user
34. anel user level controls pots can be used to create the desired mix of signals being sent to the head phone outputs Many many applications especially in production settings can benefit from this capability The desired cue sources must be carefully assigned to take advantage of the monaural mode The first cue source should be assigned using the DIP type switches to the far left channel Its output level will be adjusted by the left control The second cue source should be assigned to the right channel lts output level will be adjusted by the far right control A third cue signal sidetone can also be enabled The sidetone level Issue 1 September 2007 Page 21 Model 233 Announcer s Console control located on the far right will be used to adjust its level There is one limitation related to the head phone output mode It s the fact that the output will be 2 channel monaural What ever signal is present on the headphone output s left channel will also be present on the right channel The exception is if the right channel output is disabled A stereo headphone mix can t be created But in most cases this limitation won t overshadow the benefit of being able to create the mix For signal flow clarification please review the block diagram located at the end of this user guide Operating Modes The sixteen switches associated with switch assemblies SW3 and SW4 are used to configure the Model 23
35. ans of a flexible cable assembly This flex cable assem bly links the main printed circuit board assembly with the board assembly that contains the pushbuttons and LED indi cators Ensure that the flex cable is not damaged while the Model 233 is being customized For easier access the push button LED board assembly can also be easily removed The 3 position headers on the Model 233 s main circuit board assembly are located close to their related input or out put connectors The following list provides the printed circuit board reference num bers and associated functions P4 External 24 volt DC input pin 1 common pin 2 24 volts pin 3 not used Back panel 2 1 x 5 5 mm jack has 24 volts on center pin Header P13 is used by the back panel 24 Vdc jack assembly and is electrically in parallel with P4 P5 Headphone output pin 1 common pin 2 tip left pin 3 ring right P6 Microphone input pin 1 common pin 2 high pin 3 low Follows back panel 3 pin female XLR pin assignment P7 Main output pin 1 common pin 2 high pin 3 low Careful Back panel 3 pin male XLR has pin 1 floating pin 2 high pin 3 low P8 Line level talkback output 1 pin 1 common pin 2 high pin 3 low Careful Back panel 3 pin male XLR has pin 1 floating pin 2 high pin 3 low Model 233 User Guide Studio Technologies Inc P9 Line level talkback output 2 pin 1 common pin 2 high pin 3 low Careful Back panel 3 pin male XLR
36. asily accomplished by adding the appropriate 6 or 7 pin XLR type connec tor and making a few simple connections Other applications may benefit from hav ing mult or loop through connections something easily incorporated into a Model 233 Multi Pin Headset Connectors As previously mentioned some applica tions are best supported using headsets that interface using a multi pin connector In most of these cases the desired connec tors are 6 or 7 pin male XLR type wired to an industry standard pin out scheme Stu dio Technologies offers headset connector assemblies that allow fast and painless in stallation into a spare connector location in the Model 233 s back panel Details about these optional assemblies are available on the Studio Technologies website Issue 1 September 2007 Page 11 Model 233 Announcer s Console Options The Model 233 s standard resources are more than sufficient to directly support a large number of applications But in the real world of audio and intercommunica tions special needs always seem to arise To that end Studio Technologies offers a number of option cards In addition to passive or active components each card contains an integral connector allowing simple installation into a spare connector location on the Model 233 s back panel For interest the resources provided by some of these option cards are worth describing e The direct microphone output card p
37. at signal high or hot is provided on pin 2 Signal low or cold should be provided on pin 3 The cables shields can be connected to pin 1 But like the main output in order to minimize the chance that ground interaction problems will arise pin 1 on the line level talkback output connectors are isolated from the Model 233 s chassis and circuitry By making pin 1 float often feared ground loop problems shouldn t arise Note that the metal shell of the mating connector must also be floating The line level talkback outputs are in tended to drive the lengthy cable runs that Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console are often part of broadcast and production audio applications While the output cir cuitry is not intended to be on air quality overall audio performance should be very good Devices connected to the line level talkback outputs can range from amplified loudspeakers analog inputs on intercom systems and input channels associated with audio consoles Connecting the out puts to devices that allow easy control of the signal level can be helpful For exam ple connecting to spare input modules on an audio console provides the flexibility to add gain or attenuate as required Dedi cated talkback associated outputs on the audio console can then be routed to the final destination s As previously mentioned the line level talkback outputs on
38. com system s power Issue 1 September 2007 Page 16 External Power Input An external source of 24 volt DC power can be connected to the Model 233 by way of a 2 1 x 5 5 mm coaxial power jack which is located on the back panel of the unit The center pin of the jack is the positive connection While the requirement for the external source is nominally 24 volts correct operation will take place over a 20 to 30 volt range The Model 233 requires 90 milliamperes at 24 volts DC for correct operation Included with each Model 233 is a 24 volt DC external power supply The power supply s DC output cable has been terminated with a Switchcraft S760K coaxial power plug This locking type of plug correctly mates with the Model 2335 24 Vdc input jack The locking feature is im portant allowing the external power source to be securely attached to the Model 233 As previously discussed in this user guide an intercom line connected to the Model 233 can serve as the unit s power source Alternately an external 24 volt DC source can be connected For redundancy the in tercom line and the external source can be connected at the same time If one of them becomes inoperative the remaining source will provide power for the Model 233 The Model 233 s circuitry establishes the priority in which the unit draws its operating power If an external source of 24 volt DC power is connected it will always serve as the primary source
39. control following the configura tion selected using two of the DIP type switches Four operating modes are avail able relay disabled relay follows main output status relay follows talkback 1 status and relay follows talkback 2 status These choices were previously discussed in this user guide and should be reviewed The relay provides two form C contacts each consisting of a common normally open not shorted and normally closed shorted connection Obviously the two form C contacts change state in unison two independent relay functions are not provided These relay contacts are ac cessible on the Model 233 s main printed circuit board assembly by way of two 3 position header connectors labeled P15 and P16 The contacts are titled A and B but there is no significance between the two With both headers pin 1 is nor mally closed pin 2 is common and pin 3 is normally open For additional details on connecting to the 3 position headers Issue 1 September 2007 Page 43 Model 233 Announcer s Console please refer to the Additional Connectors section in the Technical Notes area of this user guide Specifications General Audio Frequency Response 20 Hz 20 kHz 0 1 dB mic in main out Distortion THD N 0 008 measured at 1 kHz mic in main out S N Ratio 80 dB referenced to 46 dBu mic in 2 dBu main out Connectors Mic In Line In 1 amp 2 Intercom Interface 3 pin female XLR type Mai
40. ctively used as cue sources Unfortunately there are no definitive rules regarding how best to adjust the trim pots but some suggestions may prove to be valuable Depending on how the line inputs are utilized the trim pots can be used to either adjust the absolute level of each line input signal or to ad just the relative level of the signals when compared to other sources The following examples may provide some clarification Let s begin with an application that has a stereo cue source connected to the line inputs The cue source selection switches are configured to create a stereo head phone output with line input 1 assigned to the left channel and line input 2 assigned to the right channel Begin the trim pot adjustment process by moving the user level controls located on the front panel to their detent 50 of rotation positions Then with the stereo cue source provid ing signal at its normal level adjust the trim pots to provide a comfortable level Q Talkback to Intercom ji el Line Input Level Trim i fftzsesersswne Compressor Active LED 1 Headphone Source 1 Switch1 Talkback to intercom ss SST 1 Mic Preamp 1 Gain Bt2s4se7alpi2aase7e 1 Headphone 1 Mode Select Peja act Sis ee eee 1 Phantom 1 Power ad 9 Front of Unit Figure 23 Bottom vi
41. d by both the main output and by way of the compressor circuit the talkback functions So creating a nice hot signal will help maintain audio quality specifically the signal to noise ratio when driving the often lengthy cable runs Unfortunately there s no perfect gain setting that this guide can recommend The two issues that impact the setting are output sensitivity of the connected micro phone and the acoustical output level of the microphone s user With some headset mi crophones such as the Sennheiser HMD25 selecting an initial setting of 40 dB is appro priate Users who speak loudly might need to have the gain reduced to 30 dB Quiet users might need 50 dB of gain An LED indicator is provided as an aid in correctly setting the gain of the micro phone preamplifier Red in color this LED is located adjacent to switch assembly 1 Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console It is visible by observing the bottom of the Model 233 s enclosure when the security plate has been removed Technically this red LED lights whenever the compressor Circuitry is controlling the dynamic range of the signal coming from the microphone preamplifier The threshold is set to be 2 dB above the Model 233 s nominal internal operating level So a good rule of thumb is to adjust the gain of the microphone preamplifier so that the compressor active LED lights flashes
42. ductor or production director With all the available talkback flexibility the exact needs of many specific applica tions can easily be met And of course whatever configuration is implemented the audio quality will be excellent Dynamic Range Control To enhance the Model 233 s talkback functions a studio quality compressor Circuit is provided to control the dynamic range of the signal coming from the mi crophone preamplifier Far from a simple clipper the circuit utilizes a sophisticated laser trimmed voltage controlled amplifier VCA integrated circuit for quiet low distortion level control The signal from the compressor is always used by the talkback functions For flex ibility the audio source for the main output can be selected to be either the direct output of the microphone preamplifier or the output of the compressor For on air applications the signal coming directly from the microphone preamp would be correct But having dynamic range control of the signal going to the main output can offer increased performance for selected applications These could include stadium announcement locations award show conductor positions and use with non professional announcers during sports events User Controls and Status Indicators Three pushbutton switches four LED indicators and three rotary controls Model 233 User Guide Studio Technologies Inc provide users with a clear easy to use interface On
43. e pushbutton switch controls the status of the main output This is the audio output intended for on air stadium announcement or other primary uses Two LEDs display the on off status of the main output Two additional pushbutton switches control the status of the talkback functions These are the audio cue signals used to communicate with producers directors spotters or other behind the scenes production personnel A status LED is associated with each talkback button Three rotary controls allow the user to adjust the level of the headphone output Two of the controls are associated with externally connected cue signals The third control is associated with the Model 233 s sidetone function allowing the user to monitor the signal associated with the unit s microphone input Flexibility A large part of the Model 233 s unique power is the ability to configure the op eration of the main output and talkback functions To meet the needs of the many specific broadcast and production ap plications a variety of button operating modes is available The main output button can be selected to operate from among four modes In the push to mute mode the button performs a momen tary mute of the main output In this way a cough button function is created something typically required for television sports broadcasting In the push to talk mode the button provides a momentary active function for the main output
44. each channel would connect to the other side of the pairs If the pairs also contain shields the wiring could be done somewhat differ ently One option is to connect common to both cable shields intercom channel 1 DC with audio to one full pair and inter com channel 2 to the second full pair A better option might be to have common connect to both shields and one side of the pair that serves channel 2 Intercom Audio Levels The Model 233 was designed to function well with intercom lines associated with standard broadcast and production party line intercom systems These systems provide DC power and one or two chan nels of audio over standard 3 conductor cables that terminate with 3 pin XLR type connectors Establishing the correct listen and talk levels was critical in achieving good audio performance In North America the two most common intercom systems are those from RTS and Clear Com From tests performed in Studio Technologies lab the nominal RTS TW series audio level is approximate ly 10 dBu The dynamic range control provided by belt packs such as the BP325 Issue 1 September 2007 Page 35 Model 233 Announcer s Console was very good limiting the maximum level to at most 10 dB above the nominal The nominal audio level associated with a Clear Com system was harder to char acterize It appeared to be a few dB less than 10 dBu but the dynamic range was much larger Level peaks of 10 t
45. eated Intercom Channel Crosstalk By the very nature of its design a 2 channel party line intercom circuit is prone to exhibit crosstalk This occurs because the audio paths are unbalanced single ended and are typically trans ported on a single shielded twisted pair audio cable The primary causes of the crosstalk are the common signal return wire and the capacitance between the wires in the cable pair The greater the Capacitance due to cable type and length the more crosstalk there will be It s not surprising to find in sports broadcasting venues that audio from one channel can be heard bleeding into the other channel Does this generally create a problem No But it can be a bit unnerving There are several ways of reducing inter com channel crosstalk Probably the easi est way is to use cable pairs that are not Model 233 User Guide Studio Technologies Inc twisted Twisted pairs are great for differ ential balanced signals but not so great for unbalanced transmission This is gen erally because the more twists in a pair the greater the effective cable capacitance In a stadium or arena setting choosing standard telco pairs may actually work better than high performance audio or data cable Another option is to use two cable pairs for each intercom circuit If the pairs are not shielded the wiring is simple Common would be connected to one side of each pair and then signal from
46. ed In this mode the talkback 2 button will not allow talkback audio to be sent to pin 3 of the intercom interface Issue 1 September 2007 Page 28 SW2 12 Talkback 2 to Intercom Pin 3 1234567 8910112 1234567 8910112 On Figure 22 Talkback 2 to intercom pin 3 settings e Talkback 2 to intercom interface pin 3 In this mode the talkback 2 button will control the routing of talkback audio to pin 3 of the intercom interface Pin 3 is channel 2 of an RTS TW intercom sys tem For a single channel Clear Com intercom system pin 3 is channel 1 Conclusion Once the eighteen switches have been set to the desired Model 233 s operating con figuration it may be time to reattach the security plate The exception is if the trim pots associated with the line inputs and intercom sidetone null need to be adjust ed Details are provided later in this user guide The plate attaches using the four rubber bumpers They should be hand tightened only no tools are to be used Operation At this point the desired input output and power connections should have been made The button labels may have been revised After carefully reviewing the appli cation the configuration switches should have been set Normal operation of the Model 233 can now begin The unit will begin functioning as soon as a power source is connected As p
47. ed to the right channel This would allow both IFB channel 2 and spotter audio to be heard in the head phone s right channel output To achieve this would require that switches SW2 3 Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console SW2 6 and SW2 9 be placed in their on positions Note that in some cases a user may wish to wear a headset or a pair of headphones in a left right orientation opposite of what s usual In this situation the transducer designated for the left ear would actually supply audio to the user s right ear and vice versa A specific application where this occurs is when on air talent needs to have a headset s boom microphone come across the right side of their face rather than the more typical left side In this case 55 important to select the left and right channel headphone source assignment accordingly With the Model 233 s flexible source selection there s no reason why users such as on air talent shouldn t have their cue sources assigned correctly Special applications may benefit by using the Model 233 in a 3 channel head phone output mixer mode This is accom plished by first configuring the headphone output to monaural Details on how to accomplish this are described later in this section of the user guide Next the cue source whose level is to be adjusted by the rotary control on the far left side of the front panel is assigned to the left
48. er case that would also hold a related headset cables etc A larger case could also be selected that would hold multiple Model 233 units Pelican sells their prod ucts through a dealer network many of which can be located via a web search Additional Connectors Three spare connector locations are provided on the Model 233 s back panel From the factory they contain blank plates that can be readily removed and replaced with a variety of XLR type con nectors These spare connector locations Issue 1 September 2007 Page 39 Model 233 Announcer s Console are specifically included so that a Model 233 can be customized to meet the many specific needs that arise in broadcast and related audio applications Expected uses for these locations include adding a 6 or 7 pin XLR type connector to allow direct connection of a broadcast headset Other uses include creating loop through or mult functions for the line level talkback output or intercom interface connections The spare connector locations are com patible with the Neutrik DL series of connectors For flexibility versions are available that provide from three to seven contacts For example a compatible 3 pin female connector would be Neutrik part number NC3FD L 1 To support headsets the NC6FDS L 1 is often used This is a 6 pin female connector with the unique Switchcraft 6 pin arrangement The hard ware that secures the blank plates to the Model 233 s b
49. evel level mode these two controls operate independently each controlling the level of one of the headphone output channels This mode is generally used for on air broadcast applications where independent cue signals are provided to the left and right headphone channels In the level balance mode the control on the far left sets the overall output level for both headphone channels The center control is used to adjust the balance the relative levels of the left and right channels This mode is generally best suited for applica tions where a stereo cue source is being provided SW4 1 Headphone Control Mode i Dual channel level level Stereo level balance Figure 15 Headphone control mode settings Model 233 User Guide Studio Technologies Inc Reverse Left Right Mode Switch SW4 2 is used to select whether two of the rotary controls are in the nor mal or reverse left right mode of opera tion When selected to the normal mode and level level mode is also selected the control on the far left adjusts the level of headphone output s left channel This is the signal that appears on the tip lead of the inch 3 conductor jack The center control adjusts the level of the right chan nel When selected to the normal mode and the level balance mode is also se lected turning the balance control in the counterclockwise direction
50. ew showing line input and talkback to intercom sidetone trim pots Issue 1 September 2007 Page 33 Model 233 Announcer s Console to the connected headphones The user can now in response to changing condi tions adjust the front panel level controls as desired Returning the controls to their detent positions will always provide the reference level to the headphone output A second example has the intercom input and line input 1 both providing cue sourc es Pin 2 of the intercom circuit supplies program with interrupt audio that is routed to the headphone output s left chan nel Pin 3 of the intercom circuit supplies program only audio that is routed to the right channel Line input 1 is connected to an audio source associated with a sports event spotter position This source is routed to the headphone output s right channel The input trim pot associated with line input 1 can now serve a critical role adjusting the relative level of the spotter audio as compared to the level of intercom pin 3 The trim pot allows the desired mix to be created providing the user with an effective cue signal Intercom Interface Sidetone Adjustment Associated with the talkback to intercom functions are sidetone trim potentiometers that are used to adjust the talkback levels that are returned by way of the intercom line Cue audio source circuitry These two trim pots are part of the analog hybrid cir cu
51. fier or receiver If set to the normal mode rotating the bal ance control in the counterclockwise direc tion reduces the level of the right channel providing the user with more perceived level in the left channel If set to the reverse mode rotating the balance control in the counterclockwise direction reduces the level of the left channel providing the user with more perceived level in the right channel Issue 1 September 2007 Page 31 Model 233 Announcer s Console When in the level balance mode and the minimum output level is set to 40 dB turning the level control to its fully coun terclockwise position will place both head phone output channels to 40 dB below maximum This ensures that talent will never be fully isolated from potentially important cue signals In addition rotat ing the balance control to either its fully clockwise or fully counterclockwise posi tion will cause the applicable channel to be 40 dB below its maximum If set to the full mute mode turning the level control to its fully counterclockwise position will cause both the left and right channels to fully mute In addition rotating the balance control to either its fully clockwise or fully counterclockwise position will cause the applicable channel to fully mute Both of these controls have a mechanical step detent that is located at the halfway 50 position of its rotation range The balance control will typically be set to its
52. g series resistors of no less than 560 ohms will ensure correct Model 233 operation A qualified technician can easily revise the LED colors to meet an application s exact needs The process would begin by disas sembling the Model 233 s enclosure and Model 233 User Guide Studio Technologies Inc detaching the pushbutton LED printed circuit board assembly The LEDs would then be unsoldered removed and rein stalled or replaced in the desired loca tions To control the LED current and set the brightness a resistor is electrically in series with each LED An 820 ohm 4 watt resistor is associated with the red LED while a 560 ohm watt resistor is associ ated with each green LED These resis tors would also have to be unsoldered removed and reinstalled Then the unit would be reassembled and tested to con firm that the changes function as desired For additional information about chang ing the LED colors please contact Studio Technologies technical support Travel Case For portable applications it may be desir able to store and transport each Model 233 in a protective case After much travel with prototype announcer console units Studio Technologies personnel learned to appreciate the Pelican Model 1450 case Purchased with the foam interior option it does an excellent job of holding one Model 233 its associated 24 volt DC power supply and documentation Some applications may benefit from selecting a larg
53. he sidetone function operates SW3 8 Sidetone Mode 12345678 Main button controls sidetone Main and talkback buttons control sidetone Figure 14 Sidetone mode settings Two modes are available e Main Button In this mode the sidetone function will only be active when the main output is active Main and Talkback Buttons In this mode the sidetone function will be active when ever the main talkback 1 or talkback 2 outputs are active Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console Headphone Output Operating Modes The user is provided with three rotary level controls pots that are associated with the headphone output Switches SW4 1 SW4 2 and SW4 3 are used to configure the way two of the controls the one lo cated on the far left and the one located in the center function These settings don t impact operation of the sidetone level con trol which is located on the far right With just these three switches a wide range of operating modes can be configured Care fully reviewing the capabilities of the avail able functions may prove worthwhile Dual Channel or Stereo Mode Switch SW4 1 is used to select whether the control located on the far left and the control located in the center provide a dual channel level level or stereo level balance mode of operation In the l
54. he Model 233 No Model 233 talkback audio can be effectively sent to the IFB Circuit due to its one way nature It s a low source impedance high input impedance circuit arrangement Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console The power supplied by an IFB circuit normally in the range of 28 to 32 volts DC is usually sufficient to operate the Model 233 s circuitry The acceptable input range is 24 to 32 volts with a required current of 125 milliamperes Note that the speci fied input voltage is given when measured directly at the Model 233 s IFB input con nector not at the source of the IFB circuit In North American field and in studio broadcast applications it is common to find RTS 4000 series IFB equipment be ing used to provide the IFB circuits The Model 233 can be directly connected to and function correctly with one of these circuits For reliable operation especially when using lengthy cable runs it s strong ly recommended that no other device be connected to a 4000 series IFB circuit that is specified for connection to a Model 233 This requirement is due to the current limited DC source that is supplied by the 4010 IFB Controller Phantom Power The Model 233 provides a 48 volt nominal source of phantom power to support condenser type microphones It s de signed to meet the P48 requirements as specified in the 61938 standard The Circuitry is ver
55. he button and or the main output If the Model 233 is set to the on air mode the green LED lo cated on the right is lit whenever the main output is active This could be considered as an on air or mic active indicator At the least it should serve as a careful what you say warning The red LED located on the left will be lit whenever the main output is muted This indicates that it s safe to speak as one sees fit Model 233 User Guide Studio Technologies Inc If the Model 233 s system mode is config ured for production the red LED will never light This is to reflect the fact that the main output button has now taken on a function similar to that of one of the talkback but tons To clarify wnen the Model 233 is set to the production mode the red LED will never light while the green LED will light whenever the main output is active Main Output Button Modes If the Model 233 is set for the on air mode e Push to mute If this mode is selected the main output is normally active The main output will mute whenever the but ton is pressed and held Push to talk If this mode is selected the main output is normally muted The main output will become active when ever the button is pressed and held Alternate action If this mode is selected the main output will alternate between its active and muted states whenever the button is pressed Upon power up the main output will be in its muted state Hybrid Thi
56. his could occur when the connected headset or headphones are at times placed on a desk or tabletop Main Button Mode Switch SW4 4 is used to configure how the main button responds to talkback ac tivity Specifically it applies only when the system is selected to the on air mode and the main output button mode has been configured for alternate action or hybrid When the main button mode is set to nor mal and a talkback function is active the main output will if latched on be tempo rarily placed in its off muted state When the talkback function is no longer active the main output will return to its previous latched on state When the talkback forces main button to unlatch mode is selected and a talk back function becomes active the main output will if latched on be placed in its off muted state and the latch condition forced off When the talkback function is no longer active the main output will re main in the latched off state The differences in how the main button modes impact operation and user comfort are relatively subtle The nuances of both SW4 4 Main Button Mode 01 A 345678 Normal talkback does not unlatch 4 main output 912345678 Force off talkback forces main button tHHHRHEHH to unlatch Figure 18 Main button mode settings Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console
57. ill operate normally Whenever the button is active the line level output and if configured the talkback to inter com pin 3 function will be active Main Output Source Switch SW3 7 is used to select which audio source is routed to the main output The choices are the output of the micro phone preamplifier or the output of the compressor circuit For most on air ap plications the output of the microphone preamplifier is the desired source This will provide the most natural audio quality with the potential for a large amount of dynamic range In some applications it may be desirable for the output of the compressor circuit to be routed to the main output Appropriate Issue 1 September 2007 Page 24 SW3 7 Main Output Source i Mic preamplifier HERGEERE Compressor Figure 13 Main output source settings applications could include on air broad cast situations where nonprofessional talent is present Controlling the dynamic range of the audio signals on the main output can limit the chance of cable cross talk and equipment overload Another typical application where using the output of the compressor would be appropriate when the Model 233 s system mode is selected for production In this case the main output would be used as an addi tional talkback output and dynamic range control would be beneficial Sidetone Mode Switch SW3 8 configures the way t
58. in output will mute whenever the button is pressed and held This is the cough mode typically used for on air sports broadcasting applications Push to talk In this mode the main out put is normally muted The main output will become active whenever the button is pressed and held Alternate action In this mode the main output will change between its active and muted state whenever the button is pressed Upon power up the main output will be in its muted state Hybrid This mode is a combination of push to talk and alternate action It s similar to the way talk buttons function on user stations associated with broad cast and production intercom systems If the button is pressed and held the main output will become active until the button is released If the button is mo mentarily tapped the main output will change state Upon power up the main output will be in its muted state Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console Talkback 1 Button Mode Switch SW3 3 configures how the talkback 1 button functions SW3 3 Talkback 1 Button Mode Push to talk 912345678 Hybrid press and hold to enable tap to latch Figure 9 Talkback 1 button mode settings Two modes are available e Push to talk In this mode the talkback 1 button is normally off The function becomes active whenever the b
59. inter com line can provide the DC power re quired to operate the Model 233 s circuitry An intercom line is connected to the Model 233 by way of a 3 pin female XLR type connector which is located on the back panel The mating connector male should be wired so that common is on pin 1 DC with channel 1 audio is on pin 2 and channel 2 audio is on pin 3 With single channel intercom lines common is on pin 1 DC power is on pin 2 and audio is connected to pin 3 The Model 233 s intercom interface is directly compatible with broadcast and production party line intercom lines as sociated with systems from manufactures such as RTS and Clear Com Intercom lines associated with other systems should be equally compatible RTS TW series systems are normally interfaced using 3 pin XLR type connectors These connectors are wired with common on pin 1 DC power and channel 1 audio on pin 2 and channel 2 audio on pin 3 With many Clear Com systems common is on pin 1 DC power is provided on pin 2 and audio is provided on pin 3 The DC power supplied by the connected intercom line is generally sufficient to operate the Model 233 s circuitry The acceptable input range is 24 to 32 volts with a required current of 125 milliam peres Note that the specified input volt age is given when measured directly at the Model 233 s intercom input connec tor with the connector terminated on the Model 233 and not at the source of the inter
60. it that separates nulls talkback audio from receive listen audio If audio from either or both of the intercom channels is to be used as a headphone source and talkback to these intercom channels has been configured the sidetone trim pots may need to be adjusted One trim pot is associated with the side tone level for each channel of the inter com interface Both are accessible on Issue 1 September 2007 Page 34 the bottom of the Model 233 s enclosure adjacent to the trim pots associated with the line level inputs Adjusting them is very simple requiring only a pair of ears anda screwdriver With the Model 233 configured as previ ously described activate one of the talk back to intercom functions Audio from the connected microphone may be heard in the configured headphone output channel s Adjust the trim pot associated with the active intercom channel so that the desired sidetone level relative to the intercom receive level is achieved The adjustment range is approximately 18 dB with the sidetone level increasing as the trim pot is rotated in its clockwise direc tion Now change to the other intercom channel and adjust its sidetone trim pot as desired Using the Model 233 s sidetone func tion talkback audio will be routed to the headphone outputs by means of active circuitry If this is enabled be certain to place the two intercom sidetone trim pots to their fully counterclockwise positions This will
61. l common shield is connected to both pins 1 and 3 The Model 233 is not compatible with un balanced electret type microphones that require a source of low voltage DC for op eration These microphones sometimes found in low cost headsets are not gener ally suitable for on air or other demanding applications As of the writing date of this user guide the Sennheiser HMD25 headset remains popular for on air broadcast use A fine product it works very well with the Model 233 Note that adding the suffix XQ to the headset s part number HMD25 XQ specifies a 3 pin male XLR type connector for the dynamic microphone and a 4 inch 3 conductor plug for the stereo head phones This configuration is very useful allowing the headset to work directly out of the box with the Model 233 If the writer may digress for a moment to recount a story an audio dealer once shared a secret with me concerning head sets He loved selling the lower end less expensive headset models which he did by the veritable boatload Why Because these usually broke soon after going into service He knew that on a regular basis he d receive orders for more of them Had these users from the beginning Model 233 User Guide Studio Technologies Inc purchased only premium quality headsets their total cost of ownership would have been much less Enough said Headphone Output The Model 233 s headphone output is co
62. liam peres maximum signal is capable of di rectly lighting an LED indicator or triggering an external control system The tally output is provided specifically for specialized ap plications such as television award show broadcasts where remote monitoring and control of the main output is required Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console Configuration Model 233 configurations are made using a number of DIP type switches and four trim potentiometers One 8 position switch array is used to set the gain of the micro phone preamplifier the on off status of phantom power and control of the head phone output mode A 12 position switch array configures which of the four cue audio sources as well as the sidetone au dio are routed to the headphone outputs In addition the last two sections of the 12 position switch array are used to se lect whether talkback audio will be routed to the intercom interface Two 8 position switch arrays communicate the desired operating modes to the microprocessor Two rotary trim pots are used to adjust the sensitivity of the line inputs Two ad ditional rotary trim pots are provided to adjust the sidetone null level for the inter com interface s talkback functions All switches and trim pots are accessible via the bottom of the Model 233 s enclo sure the unit does not have to be disas sembled Changes made to any of the configuration pa
63. minimize the increase in sidetone level that will occur when both the main sidetone and the sidetone associated with talkback to intercom functions are active Technical Notes Grounding and Shielding As previously discussed in this user guide the pin 1 connections on the 3 pin male XLR type connectors associated with the main and line level talkback outputs are floating i e not connected to anything within the Model 233 s enclosure Some audio experts might take offense to this grousing that this should have been left Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console to the user or installer to be connected or disconnected as desired However repeat ed field testing found that floating pin 1 on these outputs was the key to maintaining quiet audio From Fenway Park to the Orange Bowl and then northwest to Husk er Stadium lifting pin 1 always did the trick A simple solution is available if an applica tion does require that a ground be avail able on the main and line level talkback outputs interconnecting cables All Model 233 XLR type connectors have a ground connection that is made to the interfacing connector s metal shell And most XLR type connectors have a pin or connection point available to access its metal shell By connecting the cable shield to the mating connector s shell terminal the common connection typically found on audio inter connections is cr
64. mpatible with stereo or mono head phones headsets or earpieces Connect ing devices with a nominal impedance of 100 ohms or greater is preferred This shouldn t be an issue as essentially all contemporary devices already meet this condition Devices are connected to the headphone output by way of a 14 inch 3 conductor phone jack located on the Model 233 s back panel As is standard for stereo headphones the left channel is connected to the tip lead of the 14 inch headphone jack The right channel is connected to the ring lead of the jack Common for both channels is connected to the sleeve lead Devices with 14 inch 2 conductor mono plugs can also be used with the Model 2995 headphone output In this arrange ment only the tip lead left channel will be active The 2 conductor plug will physically connect short the ring lead right channel to the sleeve lead com mon Technically this won t damage the Circuitry associated with the right channel headphone output 51 ohm protection resistors are electrically in series with the headphone output circuits However energy will be wasted if an audio signal coming out of the right channel goes into a dead short There is a simple means of eliminating this issue when configuring the headphone sources simply do not assign any to the right channel head phone output Refer to the Configuration section of this user guide for details Iss
65. n Out Talkback Out 1 amp 2 3 pin male XLR type Headphone Out 14 inch 3 conductor phone jack 24 Vdc Power In 2 1 x 5 5 mm coaxial power jack with locking bushing compatible with Switchcraft S760K plug Spare Connector Locations 3 Allows up to three Neutrik NC D L 1 connectors to be installed 3F 3M 5F 5M 6F 6FS etc Microphone Input Preamplifier Type electronically balanced Input Impedance 2 k ohms Gain Range 20 to 60 dB adjustable in 10 dB steps Compatibility dynamic or phantom powered mics Phantom Power 48 Vdc nominal meets IEC 61938 Compressor Threshold 2 dB above nominal level Attack Release Time 2 mSec 100 mSec Slope 5 1 Status LED compressor active Line Inputs 2 Type balanced transformer coupled Impedance 10 k ohms Nominal Level 12 dBV to 6 dBu adjustable Intercom Interface Type 2 channel unbalanced pin 1 common pin 2 DC with channel 1 audio pin 3 channel 2 audio Compatibility single and dual channel intercom systems such as from RTS and Clear Com Issue 1 September 2007 Page 44 Impedance 10 k ohms Nominal Receive Level 10 dBu Nominal Talkback Level 10 dBu Sidetone Null 0 to 18 dB adjustable Main Output Type balanced transformer coupled Nominal Level 2 dBu Maximum Level 20 dBu into 2 k ohms Impedance 100 ohms Line Level Talkback Outputs 2 Type transformer coupled with series capacitors and isolation resistors Impedance
66. n the sidetone signal will always be fully muted Astute readers will realize that sidetone au dio can also be provided from the intercom cue sources during Model 233 talkback to intercom activity This passive sidetone is created in the intercom interface s ana log talk listen hybrid sidetone null circuit Trim pots allow the intercom sidetone level to be adjusted over a limited range To get maximum performance when either or both intercom channels are used as a cue source one simple calibration process may need to be performed This involves ad justing the sidetone null trim pots to their fully counterclockwise positions providing minimum sidetone level This will reduce the level build up that would occur when both the main and the intercom sidetone audio signals are sent to the headphone output The goal is for the sidetone level to remain as constant as possible no matter what function main output talkback to line level output or talkback to intercom is active Advanced Operation Adjusting the Line Input Trim Pots As has been previously mentioned associ ated with the two line inputs are trim pots that allow the input levels to be adjusted The two trim pots are accessible by way of round openings in the bottom of the Model 233 s enclosure By adjusting these trim pots signals with a nominal signal level of Model 233 User Guide Studio Technologies Inc 12 dBV to 6 dBu can be effe
67. nated as SW1 1 SW1 2 etc The switch assemblies are accessed through openings in the bottom of the Model 233 s enclosure The enclosure does not have to be disassembled to gain access to the switches To prevent unauthorized personnel from changing the configuration settings a se curity plate is attached to the bottom of the Model 233 s enclosure For convenience attached to the security plate is a configura tion settings label It provides a summary of the configurable parameters and related information Refer to Appendix A for a representative view of the label The secu rity plate is held in place by means of four rubber bumpers feet that have built in screws Using your fingers remove the four bumpers so that the plate can be removed Refer to Figure 3 for a detailed view of the configuration switch assemblies Issue 1 September 2007 Page 17 Model 233 Announcer s Console QO Q Talkback to Intercom Sidetone Level Pin 2 Pin 3 ine Inj Line Input Level Trim 4 4 Switch 2 1 1 Compressor n Active LED 1 Headphone 1 Talkback to Intercom bt 2345678 h Q Front of Unit Figure 3 Bottom view of Model 233 showing configuration switches trim pots and compressor active LED Microphone Preamplifier Gain and Phantom Powe
68. nd outputs make extensive use of protection components This limits the chance of damage from ESD and other undesirable yet real world hazards Issue 1 September 2007 Page 10 Power Sources The Model 233 can derive its operating power from an intercom line or an external 24 volt DC source For redundancy both power sources can be connected simul taneously An internal switch mode power supply ensures that all Model 233 features are available including phantom power when the unit is powered by either source Auxiliary Relay Model 233 resources include a general purpose relay allowing specialized configu rations to be created Under software con trol the relay can be configured to follow the state of the main output talkback 1 or talkback 2 buttons Taking advantage of the back panel locations provided for additional XLR type connectors a techni cian may easily create functions such as an on air indicator or implement a loud speaker muting during talkback function Special configuration modes are even included to allow direct control of the relay using the talkback 1 or talkback 2 buttons without impacting any of the Model 233 s audio signals Tally Output Another unique Model 233 feature is the tally output It provides an indication in the form of a current limited DC signal of the status of the main output Whenever the main output is active the tally output is active This 3 5 volt nominal 12 mil
69. nnouncer s Console SW2 1 through SW2 5 Left Channel Headphone Source Selection Line In 1 Line In 2 Intercom Interface Pin 2 Intercom Interface Pin 3 P Sidetone microphone input 456789101112 On to enable source multiple sources will sum lo N t RTS TW Channel 1 RTS TW Channel 2 Clear Com Channel 1 SW2 6 through SW2 10 Right Channel Headphone Source Selection Line In 1 Line In 2 Intercom Interface Pin 2 Intercom Interface Pin 3 Sidetone microphone input 1234567 8910112 On to enable source multiple sources will sum RTS TW Channel 1 RTS TW Channel 2 Clear Com Channel 1 Figure 6 Left and right channel headphone source selection settings The line inputs are interfaced using two connectors also located on the back pan el Associated with line inputs 1 and 2 are level trim potentiometers They are pro vided so that audio sources with a wide range of nominal levels can be effectively used as cue sources Please refer to the Advanced Operation section of this user guide for details on using the trim pots Audio associated with intercom channels 1 and 2 is provided by way of the intercom interface whose connector is also located Issue 1 September 2007 Page 20 on the back panel Two trim pots are associated with the intercom channels They allow adjustme
70. nt of the intercom sidetone null level This impacts the amount of talkback audio signal that is returned to a headphone output when a talkback to intercom function is active The sidetone audio source comes from the output of the compressor circuit as sociated with the microphone preamplifier This allows an announcer or other Model 233 user to receive a confirmation signal of what is coming out of the main and if configured talkback outputs As previously discussed each of the avail able input sources can be assigned to the headphone output s left channel right channel or both the left and right chan nels The Model 233 s circuitry allows any combination of input assignments to be made For example consider the situation where a single channel intercom line with audio present only on pin 3 is connected In this case it may be desirable to assign this intercom audio source to both the left and right channels This would entail set ting switches SW2 4 and SW2 9 to their on positions All other switches would remain in their off positions A more complex application might have a broadcast type 2 channel IFB circuit connected to the intercom input and a line level audio signal from a golf event spotter connected to line input 1 In a case such as this it would be typical for IFB channel 1 to be assigned to the headphone s left channel IFB channel 2 assigned to the right channel and line input 1 also assign
71. o 20 dB over nominal were easy to produce This objective data led to the following Model 233 design decisions When audio from intercom channels 1 and 2 was used as headphone cue sources level sensitiv ity selection switches or trim pots were not required The level range available on the Model 233 s front panel controls proved to be sufficient for the user to be able to establish the desired listening level When talkback audio was routed to the intercom channels a single audio level proved to work well with both RTS and Clear Com systems This was mainly possible due to the excellent dynamic range control provided by the compressor circuit Its threshold 2 dB above Model 233 internal nominal level and compres sion ratio 5 1 resulted in excellent talk back to intercom audio So in the end no level or compatibility switches of any kind were required to achieve the desired listen and talk performance The above paragraphs may elicit howls of protests from a host of engineers and intercom system experts But for years we ve heard differing reports as to the actual nominal audio levels for RTS and Clear Com systems The in the know cats agreed that RTS TW intercom and IFB was 10 dBu a value that we con firmed in our tests But the nominal level for Clear Com was variously reported as 20 15 12 10 and you know the Clear Com level It s most likely that early Issue 1 September 2007 P
72. o the talent s left ear while the right control impacts the right The sidetone level control is dedicated to adjusting the level of the mic audio signal that s routed to the headphone outputs Configuration switches allow which of the headphone outputs left right or both will receive the sidetone signal When the sidetone level control is set to its minimum position the sidetone level is always set to be fully muted Provision has been made to support ap plications where a monaural cue feed is desired A configuration switch allows the summing combining of the selected left and right headphone sources In addition to creating a dual channel mono output it also allows the level controls to be config ured as a simple 3 channel mixer The headphone output is optimized to meet the needs of contemporary head phones and headsets Specifically the output circuits act as voltage rather than power drivers In this configuration they can provide high output levels with very low distortion and noise along with mini mal current consumption The output cir cuits are configured to safely drive stereo or mono loads This ensures that all types of headphones headsets and earpieces can be directly connected Issue 1 September 2007 Page 9 Model 233 Announcer s Console Intercom Interface Of special note is the Model 233 s sophisti cated intercom interface It s designed to work correctly with industry
73. ono 60 dB 50 dB 40 dB 30 dB 20 dB 4 Switch 1 Mic Preamp Gain Headphone Mode Select Phantom Power Preamp Gain select one only Compressor Active LED 9 Headphone Minimum Headphone Reverse Headphone Controls Headphone Stereo Mono Y Stereo A Mono Phantom Power 48 V y Off A On Talkback 1 to Intercom Pin 2 Yy Off A On Y On air Headphone Minimum Y 40 dB A Full mute A Production Talkback 2 to Intercom Pin 3 Vv Off A On Label 15193 RevA Model 233 User Guide Studio Technologies Inc LINE DRIVER 600 600 2 MAIN OUTPUT XLR Me 48V Hace m gt 5 PREAMPLIFIER Nc gt 1 PHANTOM LINE DRIVER MICROPHONE POWER PROTECTION COMPRESSOR INPUT 3 Gani 600 600 300 XLR F AW i 2048 TALKBACK OUTPUT 1 300 3 XLR Me ON OFF 3048 Nc gt 1 4048 LINE DRIVER 5048 600 600 300 6048 AWW TALKBACK OUTPUT 2 300 3 XLR M Zs 4 Bu COM abo NC Not j gt AUXILIARY RELAY i CONFIGURAT
74. phone connected as the input source one should never use the 0 dB setting The issue is that with no gain added to the microphone input signal the relative noise floor on the circuitry associated with the main output and talkback functions will be much too high These circuits are designed for handling line level signals expecting to receive audio from the output of the micro phone preamplifier In conclusion the 0 dB gain setting doesn t highlight a problem but simply reflects the unit s gain structure Phantom Power On Off The Model 233 can provide nominal 48 volt phantom power to the microphone input Switch SW1 8 controls whether or not phan tom power is active By phantom power s very nature it could be left applied to the microphone input at all times But generally people prefer to turn it off unless required for a specific microphone SW1 8 Phantom Power 48 V On Figure 5 Phantom power switch settings Headphone Source Selection Switch assembly SW2 is used to configure the sources that are routed to the ste reo headphone output Five headphone sources are available line input 1 line in put 2 intercom channel 1 intercom chan nel 2 and sidetone Each of these sources can be assigned to the left right or both the left and right channels of the stereo headphone output Issue 1 September 2007 Page 19 Model 233 A
75. pplications that include on air television and radio broadcasting stadium announce ment and simultaneous interpretation In addition with the unit s broad range Figure 1 Model 233 front panel Model 233 User Guide Studio Technologies Inc Issue 1 September 2007 Page 5 Model 233 Announcer s Console lt E o MODEL 233 ANNOUNCER S CONSOLE STUDIO TECHNOLOGIES INC www studio tech com MADE IN USA 9001010190 INTERCOM LINE IN 2 UNE IN 1 aa MAIN OUT MIC IN Figure 2 Model 233 back panel of capabilities many other specialized behind the scenes applications can also be implemented System Features Microphone Input A high performance microphone preampli fier circuit provides low noise low distortion amplification over a 20 to 60 dB gain range The gain is adjustable in 10 dB steps The input is compatible with balanced dynamic and condenser microphones The micro phone power source is 48 volts nominal and meets the worldwide P48 phantom standard An LED indicator serves as an aid for optimizing the preamplifiers gain setting The output of the microphone pre amplifier is used by the main output as well as being routed to the compressor circuit that supports the talkback functions Main Output The Model 233 provides a main output that is designed to serve as the on air stadium announcement or other primary audio feed Nominally 2 dBu it is designed as a fully
76. r Five switches are used to set the gain of the microphone preamplifier One switch is used to select the on off status of the phantom power supply Microphone Preamplifier Gain Switches SW1 1 through SW1 5 are used to select the gain of the microphone preampli fier The choices are 20 30 40 50 and 60 dB Only one switch should be enabled at a time There s no problem changing the gain setting while the unit is operating Audio clicks or pops might occur during gain tran sitions but this shouldn t be a major issue as long as associated monitor loudspeak ers are temporarily attenuated or muted Selecting the correct amount of gain for an application might take a little experimenta tion The goal is to bring the microphone s Issue 1 September 2007 Page 18 SW1 1 through SW1 5 Mic Preamp Gain alee All BEE tuAWWWHEY 12845678 td A EEE 40 dB 50 9B gi 5678 60 48 HOGER 0 dB no gain Factory use only Figure 4 Microphone preamplifier gain switch settings signal up to line level nominally 2 dBu on the Model 233 s main output Operating at this signal level will help to ensure the delivery of clean audio to the connected device The output of the Model 233 s mi crophone preamplifier is use
77. rameters become active immediately To prevent access to the configuration controls a security panel included with each unit is attached to the bottom of the enclosure Connectors The Model 233 uses standard connectors throughout The microphone input line inputs and intercom interface functions use 3 pin female XLR type connectors The main and line level talkback output functions use 3 pin male XLR connectors The headphone output utilizes a inch 3 conductor jack The external source of 24 volt DC power is connected by way 8 2 1 x 5 5 mm locking coaxial power jack Model 233 User Guide Studio Technologies Inc Additional Connector Locations In the world of broadcast production and public address audio it s fair to say that applications vary widely To this end up to three additional XLR type connectors can be easily mounted into the Model 233 s back panel Multiple 3 position neaders located on the Model 233 s circuit board provide technician access to literally every input and output connection In addition some additional features including the remote control inputs and tally output are accessible using 3 position headers Using a factory available interface cable kit these headers allow a Model 233 to be optimized to meet the exact needs of specific applica tions For example some applications may prefer to use a multi pin XLR type connec tor to interface with a headset This could be e
78. reviously dis cussed power for the Model 233 can be provided by an intercom line or an exter nal source of 24 volt DC It s important to highlight the fact that the Model 233 is an active device Audio signals will not be Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console present on the outputs unless power has been supplied Specifically the micro phone does not passively cut through to the main output connector Upon Model 233 power up the four status LEDs will light in succession as a firmware boot up indication The unit will then begin normal operation Depending on the selected configuration one LED as sociated with the state of the main output may be lit The user is now presented with three buttons four LEDs and three rotary controls These are simple to operate and understand as will be described in the fol lowing paragraphs Pushbutton Switches and Status LEDs Three pushbutton switches are used to control the main output and the talkback functions The way each operates de pends on the selected configuration Four LED indicators are located adjacent to the buttons They reflect the status of the main output and talkback functions Main Output Button and LED Indicators The button on the left factory labeled as COUGH functions according to the se lected configuration Two LED indicators located directly above the button are associated with the status of t
79. rovides access to the dynamic or con denser microphone that is connected to the Model 233 s mic input Passive components along with the auxiliary relay contact create a click free microphone level audio signal e The remote switch input card uses a 4 pin XLR connector to provide access to the Model 233 s remote switch inputs Other general purpose option cards provide 3 pin XLR 4 pin XLR and 8 pin EtherCon connectors With the range of option cards available it s hard to imag ine an application that can t be served But you re welcome to try to stump the chumps in the Studio Technologies technical support department But first please check the complete list of the available option cards listed on the Studio Technologies website Issue 1 September 2007 Page 12 Installation and Setup In this section interconnections will be made using the input and output connec tors located on the Model 233 s back pan el Microphone line level audio sources intercom main output and line level talk back output signals are interfaced by way of 3 pin XLR type connectors A 4 inch 3 conductor phone jack is provided for the headphone output A 2 1 x 5 5 mm coaxial jack allows connection of an external 24 volt DC power source System Components The following is included in the shipping carton Model 233 Announcer s Console user guide button label sheet and 24 volt DC power supply For units shipped
80. s the main output will utilize the signal com ing directly out of the microphone preampli fier The gain element in the compressor Circuit is a laser trimmed voltage controlled amplifier integrated circuit It provides accu rate low noise low distortion performance The threshold of the compressor circuit is 2 dB above the Model 233 s nominal inter nal operating level of 2 dBu A 5 1 com pression ratio is implemented and like the threshold level is not field adjustable The threshold and ratio settings were selected so that excellent talkback audio would be provided By controlling the dynamic range intelligibility can be improved and overload ing of connected devices can be avoided Model 233 User Guide Studio Technologies Inc An LED indicator lights whenever the compressor s threshold has been reached and the circuit is actively controlling the dynamic range This LED is provided as an aid when setting the gain of the micro phone preamplifier Auxiliary Relay The Model 233 provides an auxiliary relay for use in specialized applications Some head scratching or brainstorming should lead to a number of interesting ways to take advantage of this unique resource To implement any auxiliary relay application does require the services of a qualified technician This is because the Model 233 s enclosure must be disas sembled and the desired wiring scheme implemented The relay operates under software
81. s will be assigned to the control on the far left and the control in the center channel serving as two of the mix sources How these two controls respond when placed in their fully counterclockwise position will depend on the configuration By default the output level will be 40 dB below its maximum level An alternate configuration will make the outputs mute The control on the far right sidetone will always maintain the same function It is used to add signal associated with the microphone input to the headphone output as desired Sidetone Operation As previously covered in this user guide a sidetone function can be configured Sidetone is defined as the user s own voice signal being returned to them as a headphone cue source This helps the user create a more effective performance as well as possibly receiving an on air or you re live indication Depending on how it was configured sidetone audio will be sent to the left headphone output the right headphone output or both the left and right headphone outputs In addition the side tone function can be configured so that it is active only when the main output is active or whenever the main output or Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console one of the talkback outputs is active The level control on the far right adjusts the side tone level When the sidetone level control is in its fully counterclockwise posi tio
82. s mode is a combination of push to talk and alternate action It is similar to the way that talk buttons function on user stations associated with broadcast or production intercom systems If the button is pressed and held the main output will become ac tive and remain active until the button is released If the button is momentarily tapped the main output will change state Upon Model 233 power up the main output will be in its muted state Talkback activity will always cause the main output to be placed in its off state If the main output was in the latched on Issue 1 September 2007 Page 29 Model 233 Announcer s Console state when talkback began once talk back activity ends that state will resume the main output will again be in its on latched state Talkback 1 Button and LED Indicator The button in the center factory labeled TALKBACK 1 controls the function s as sociated with talkback 1 The manner in which the button functions depends on the way it was configured An LED indi cator green in color is located directly above the button It lights whenever talk back 1 is active If the talkback 1 function mode has been configured for disabled it will light only if the auxiliary relay has been assigned to follow the talkback 1 button If the Model 233 has been selected to the on air system mode whenever talkback 1 is active the main output will be placed in the muted state If the Model 233
83. standard single and dual channel party line inter com systems including those from RTS and Clear Com An intercom line connect ed to the Model 233 can serve three func tions providing cue audio signals to the headphone output allowing talkback audio to be sent to intercom users and acting as a Model 233 power source Audio sig nals present on the single or dual channel intercom line can be flexibly routed to the stereo headphone output Talkback audio controlled by the two talkback pushbutton switches can be sent to either or both of the intercom channels Trim potentiom eters located on the bottom of the unit al low adjustment of the talkback to intercom sidetone null level Other announcer console products can exhibit talkback to intercom related audio oscillations squeals that end up in the headphone output A unique Model 233 feature ensures that this will never occur This is accomplished by means of a special auto terminate circuit that becomes active whenever an intercom line is not connected to the Model 233 Audio Quality and Protection The Model 233 s circuitry is carefully tailored to provide excellent audio perfor mance Professional quality components are featured throughout For reliability all audio routing is performed using solid state devices under microcontroller direction In all critical audio paths clickless electronic switches provide noise free control All audio inputs a
84. t 2 Button Modes e Push to talk If this mode is selected the function s associated with the talkback 2 button is normally off The function s will become active whenever the button is pressed and held Hybrid This mode is a combination of push to talk and alternate action If the button is pressed and held the function s associated with the talkback 2 button will become active until the button is released If the button is mo mentarily tapped the function s will change state Upon Model 233 power up talkback 2 will be in its off state Headphone Output Level Controls Three rotary controls pots are located on the Model 233 s front panel and are associated with the stereo headphone output The manner in which the controls function depend on the selected con figuration The control on the far right is associated with the sidetone function It s operation will be discussed in a later section One configuration parameter sets the control on the far left and the control in the center to operate in a level level or a level balance mode Another parameter allows the left right assignment of the Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console controls to be reversed A third parameter selects whether the headphone output channels will maintain a minimum output level or can be fully muted In most cases the headphone output will be configured for stereo rather than monaural
85. tations must be discussed The first is that button back lighting is not intended to serve tally appli cations A common connection to power all three lamps is provided independent access to the lamp connections on each button is not provided It is strictly in tended to provide a moderate amount of illumination to the button s lens and as sociated labeling The second restriction is that power for the backlighting function cannot be provided by an intercom line it was felt that there may not be enough current available from this source to power both the Model 233 and light the lamps However power from the external 24 volt DC source can be used This requires that this power source be connected whenever backlighting is desired From the factory lamps bulbs are not installed in the pushbutton housings They are pluggable T 1 bi pin type and are simple to install The mating socket is accessed by removing the button s lens caps graphic label and back frosted lens Compatible incandescent lamps with a nominal rating of 18 volts 28 mA are available from Studio Technologies part number 12030 Bulbs with other nominal voltages should also be available from electronics parts vendors While compat ible LED based lamps are probably also available incandescent lamps when pow ered below their rated current and voltage can provide extremely long and reliable operation A 3 position header connector labeled P14
86. to des tinations in Japan and North America the power supply will have a nominal AC mains input of 120 volts For all other destinations a power supply compatible with 220 240 volt AC mains will be included Microphone Input The Model 233 is compatible with balanced dynamic and condenser microphones Depending on the application the micro phone may be part of a headset or be an independent handheld or stand mounted model The Model 233 s nominal 48 volt power source will support essentially all phantom powered microphones The qual ity of the Model 233 s microphone pream plifier and associated circuitry is such that special applications may benefit from using high end microphones If selected appro priately models from manufacturers such as AKG Beyerdynamic Crown Neumann Sennheiser and Shure will perform very well in Model 233 applications Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console The selected microphone is intercon nected by way of a 3 pin female XLR type connector which is located on the Model 233 s back panel The mating connector male should be wired so that pin 2 is signal high or hot pin 3 is signal low or cold and pin 1 is shield It s possible that an unbalanced microphone will also work correctly but is not recommended However if this is necessary the mating connector male should be wired so that pin 2 is signal high or hot and signa
87. ue 1 September 2007 Page 13 Model 233 Announcer s Console Main Output The Model 233 s main output is intended to be the on air or primary signal that typi cally connects to the input of an audio con sole The output is transformer balanced with a nominal signal level of 2 dBu The actual level will depend upon the gain set ting of the microphone preamplifier sen sitivity of the microphone and how loudly the user speaks into the microphone The transformer used in the main output is in tended for professional audio applications Its source impedance is very low and can drive lengthy cable runs without difficulty It is capable of driving loads as low as 600 ohms but performs best with loads of 2 k ohms or greater This should not prove to be an issue as virtually all contemporary audio equipment has a relatively high input impedance As the secondary winding of the output transformer connects directly to the main output connector care should be taken so that a DC voltage is never present on the interconnecting cable The main output is interfaced by means of a 3 pin male XLR type connector located on the Model 233 s back panel The inter connecting cable s mating connector female should be wired so that signal high or hot is on pin 2 and signal low or cold is on pin 3 The cable s shield can be connected to pin 1 but it will have no function Also the cable s shield must not be terminated
88. utton is pressed and held Hybrid This mode is a combination of push to talk and alternate action If the button is pressed and held the talkback 1 button will become active until the button is released If the button is mo mentarily tapped the state will change Upon power up the talkback 1 button will be in its off state Talkback 2 Button Mode Switch SW3 4 configures the way the talk back 2 button functions SW3 4 Talkback 2 Button Mode Push to talk 01 2445676 Hybrid press and hold to enable tap t to latch Figure 10 Talkback 2 button mode settings Model 233 User Guide Studio Technologies Inc Two modes are available e Push to talk In this mode the talkback 2 button function is normally off The func tion will become active whenever the button is pressed and held Hybrid This mode is a combination of push to talk and alternate action If the button is pressed and held the talkback 2 button will become active until the button is released If the button is mo mentarily tapped the state will change Upon power up the talkback 2 button will be in its off state Talkback 1 Button Function Switch SW3 5 configures the overall operation of the button associated with talkback 1 SW3 5 Talkback 1 Function Mode 012345678 Disabled unless assigned to relay
89. volts This power supply circuit works very well as long as it is fed with sufficient input voltage and cur rent Sufficient is defined as a minimum of 24 volts on the intercom input and 20 volts on the external 24 volt DC input The necessary current 125 milliamperes for the intercom line and 90 milliamperes for the external source must be supplied over their respective voltage ranges It s worth discussing what will happen if any of these power sources fall below their specified minimum Typically if the Model 233 is being powered by an external 24 volt nominal power source normal opera tion will continue until the input falls to the 18 20 volt range As the input voltage drops below this range the Model 233 s internal power supply will have reduced stability operating in this manner until its low voltage shutdown circuit halts opera tion Note that as the input voltage moves down from 24 volts the input current will rise proportionately to make up for the loss of power Using the intercom line to provide Model 233 power shouldn t prove to be a prob lem Power supplies associated with broadcast and production intercom sys tems are designed to support multiple belt pack and related devices In the big scheme of things connecting a Model 233 shouldn t add a significant load Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console LED Colors As previously described
90. when the connected microphone is sending signal peaks During normal operation the LED should not remain fully lit when typical audio sig nals are present on the mic input It s important to remember that the com pressor active LED is used to assist in set ting the mic preamplifier gain to the optimal value It doesn t necessarily indicate that the main output s signal is being compressed Unless specifically configured to perform otherwise the output of the compressor is only used for the talkback output functions It s expected that the 20 and 60 dB gain settings will not often be used But there are always exceptions and that s why they were included It s possible that with a very hot microphone such as a phantom powered condenser type 20 dB of gain could be correct It s also possible that a microphone with a very low level output such as a ribbon type would need 60 dB of gain But in general the 30 40 and 50 dB gain settings will serve most applications Note that if no gain switch is set to its ac tive on position the Model 233 s preampli fier will operate at unity 0 dB gain In this mode the preamplifier will remain stable but is intended only for use during factory testing A valid exception would be where Model 233 User Guide Studio Technologies Inc a line level signal is connected to the microphone input This could occur with a special Model 233 application But with a micro
91. which can be selected for routing to the stereo headphone output The sources are line input 1 line input 2 intercom channel 1 and intercom channel 2 Each source can be individually assigned to the left channel the right channel or both the left and right channels This allows a wide variety of stereo and mono head phone mixes to be created For application flexibility two line level audio sources can be connected to the Model 233 Possible signal sources Issue 1 September 2007 Page 8 include off air receivers wireless IFB sys tems and audio consoles The connected signals can be from two independent sources or could be from a stereo audio feed such as would be associated with a broadcast music event Two level trim po tentiometers located on the bottom of the unit allow signals with wide nominal audio levels to be cleanly interfaced Audio signals associated with a single or dual channel intercom system can be routed to the headphone output The Model 233 s intercom interface is com patible with standard party line intercom systems from manufacturers such as RTS and Clear Com A broadcast type IFB interrupted foldback circuit can also be connected to the intercom input This listen only signal is often found in televi sion broadcast applications Sidetone The Model 233 includes an integrated sidetone function that allows the output of the compressor circuit associated with the microphone pre
92. y website www digikey com To make the process of connecting to the Model 233 s headers a simple task an interface cable kit part number 31087 is available from Studio Technologies Each kit includes five cable assemblies and a length of heat shrinkable tubing Each cable assembly consists of a mating con nector with three color coded wires at tached These wires nominally 12 inches in length allow convenient soldering to a connector slated to be installed in a spare location on the Model 233 s back panel For reference the wire color for pin 1 is gray pin 2 is yellow and pin 3 is blue The heat shrinkable tubing is provided so that the connector solder cups can be insulated from each other It will also pro vide some strain relief to the solder joints Be certain to slip the desired length of tub ing over the wire prior to soldering a con nection If this writer had a dollar for every time he forgot to put tubing on a wire or slip on a connector shell before making a solder connection The Model 233 s enclosure must be disassembled prior to installing connec tors in the spare locations Four hex head machine screws two on the bottom front Model 233 User Guide Studio Technologies Inc Model 233 Announcer s Console of the enclosure and two on the back panel must be removed A 5 64 inch hex driver is required The cover can then be carefully separated from the chassis remaining attached by me
93. y simple two 6 81 k ohm 1 tolerance resistors provide a path from a 48 volt DC source to pins 2 and 3 of the microphone input connector The resistors and the power source work together to provide the required 48 4 volts up to a maximum current of 10 milliamperes External Power Sources As has been previously discussed an external source of 24 volt DC can be used to power the Model 233 While develop ing the 200 series of announcer console Model 233 User Guide Studio Technologies Inc products an interesting phenomenon was discovered regarding acceptable sources To meet worldwide requirements using a compact switch mode universal input power supply seemed to be an excellent solution Supplying one of these with each Model 233 would have allowed operation anywhere in the world Whether connect ing to 100 volts 60 Hz in Japan or 240 volts 50 Hz in Australia all would be well Unfortunately things did not work out as planned It turned out that all of the com pact switch mode power supplies that were tested induced a great deal of noise into their DC output This noise especially noticeable in the negative lead of their DC output fed right into the common lead of the intercom circuit From what could be determined noise current would travel from the power supply through intercom input pin 1 and on to the intercom line s source s ground connection Making the problem more insidious was the fact that onl
94. y when the intercom line s intercon necting cable was sufficiently long did the problem become noticeable In the lab where 10 foot long test cables were used the audio from the intercom line was extremely quiet But testing with 500 or 1000 feet of interconnecting cable resulted in an annoying buzz on the intercom audio channels Many hours were spent trying to eliminate this problem But unfortunately no solu tion was found It was a humbling expe rience that only a few visits to the local tavern made us feel better about The solution turned out to be very simple but not without other ramifications By changing to a low cost transformer based linear 24 volt DC power supply the problem disappeared With no high frequency switching noise to get into Issue 1 September 2007 Page 37 Model 233 Announcer s Console the intercom line everything worked well But a new problem arose when it came to finding an external linear power supply for Model 233 users worldwide For loca tions that are served by 100 or 120 volts 60 Hz a 24 volt DC linear wall wart pow er supply was readily available This is the power supply that is provided with Model 233 units shipped to North America or Japan But as of this writing no perfect 24 volt DC linear power source has been located that would serve 220 240 volts 50 Hz applications So a compromise had to be made For these applications a uni versal

StudioTech Annoucer's Console 233 User's Manual

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