Grace Design m201
Contents
1. r 1 C 1 Microphone Preamplifier ADC 4689 Ute Highway Lyons 80540 USA OME su sr tel 1 303 823 8100 fax 1 303 823 8101 All contents 2012 Grace Design info gracedesign com www gracedesign com Welcome Thank you for purchasing the Grace Design m201 microphone preamplifier With the combination of unmatched sonic performance useful features and solid reliability the m201 is a powerful recording tool designed to help you make the best recordings of your career We have designed the m201 to be as easy and intuitive to use as possible However we strongly recommend that you read this product manual thoroughly to familiarize yourself with the unique features and capabilities of the m201 Also please do not hesitate to contact us directly if you have any questions comments or concerns with your new m201 microphone preamplifier Thanks for reading and happy recording The Grace Design Team Contents Welcome Important Safety Information Front Panel Controls Rear Panel Connections Audio Connections Power Connections Preamplifier Operation The Optional A D Converter Features Operating The A D Converter Module NO o N O O W N Adjusting A D Converter Sensitivity _ Maintenance _ Specifications Signal Flow Diagram Warranty Information N Manual Revisions grace design m202. Added power mains disconnect informaton 04 26 2007 5 haea signal fow diagem 0426200 Added A D module ination 10802 5 chanoeg fuse values for 220250 fiom 25016 3t5mA 4 24 08 fe s Fixed rearpane panelilustation anses C F 7 Changes Fuse Table values formating Note that DPA option is no longer available ssers 20 grace design m201 owner s manual
3. becomes inadvertently changed to 48V 48V phantom will consequently be activated which can potentially harm a ribbon your microphone if it is still connected to the input If the 48V phantom power switch is turned of and then the ribbon mode is selected the preamplifier will wait until the phantom pow er voltage has completely discharged and then the ribbon mode will activate automatically An additional benefit of the ribbon mic mode is that the input DC blocking capacitors are relay by passed to further simplify the m201 s signal path Incidentally the ribbon mode works very well with many lower output dynamic microphones as well as ribbon types M S RECORDING In M S mode the m201 accepts the Mid signal in channel 1 and the Side signal in channel 2 The LEFT channel output connector provides the sum of the inputs and the RIGHT channel output connector provides the difference of the inputs In M S mode the M S width control adjust the ratio of Mid signal to Side signal in the dedicated M S outputs The LEFT and RIGHT M S outputs are always ac tive which allows the user to record the discreet Mid and Side signals from the preamplifier Channel grace design m201 owner s manual 1 and 2 outputs while also recording monitoring the stereo composite from the 5 LEFT and RIGHT outputs Note For more information on M S recording we would highly recommend the AES pa per written by Wes Dooley and Don Streicher called M S Stereo A Pow
4. is reached If the peak indicator flashes red excessively with the gain control in the fully counterclockwise position engage the 20dB attenuator When sending a signal to a recorder with an input attenuator i e the record level control on a DAT or CDR recorder use the following procedure With the sound source present turn the gain control clockwise until the peak LED begins flashing red then reduce the gain until the red stops flash ing Since red indicates a peak level which is 12dB before preamplifier clipping 6dB in unbalanced mode it is OK for it to come on periodically during recording If peak indicator flashes red exces sively with the gain control in the fully counterclockwise position engage the 20dB attenuator Now adjust the recorder input control for the optimum recording level RIBBON MIC MODE Selecting the ribbon mic position on the input mode switch optimizes the channel for ribbon micro phones by boosting the gain by 10dB while disabling 48V phantom power and optimizing the mic input impedance Before activating ribbon mic mode make sure the channel s gain is fully down counter clockwise and 48V phantom power is off Now simply select ribbon input mode and turn the gain control upwards until the proper recording level is achieved If you press the 48V phantom switch while the ribbon switch is engaged the mic power will not turn on However if the 48V phamtom switch remains depressed and the input mode switch
5. pin XLR connectors Note this option is no longer available 6 Optional A D Converter module Optional A D converter module for the m201 in cludes seperate balanced analog A D line inputs 2x AES3 outputs single and dual wire word clock loop sync in and out S PDIF out and TOS LINK optical out grace design m201 owner s manual Audio Connections Microphone input connections are made via female XLR connectors with pin 2 positive pin 3 nega tive and pin 1 ground 48V phantom power is supplied on pins 2 and 3 Output connections are made via male XLR connectors with pin 2 positive pin 3 negative and pin 1 ground If the output is to be used unbalanced pin 1 should be connected to signal ground and pin 2 to signal hot Due to the nature of the balanced output stage pin 3 should be left open for unbalanced operation See figure 1 gt below Note This will provide a signal of positive absolute polarity when the preamplifi er is being used with a microphone which produces a positive voltage on pin 2 with positive air pres sure on the front of the diaphragm While a vast majority of microphones conform to this standard a few do not Use the phase reverse switch to compensate if necessary CX val SHIELD 3 open figure 1 Unbalanced output cable termination To connect to the front panel HI Z input the input mode selector switch must be positioned in the HI Z location which changes the preamplifier input
6. to adjust If the current signal level is high you need to decrease the A D sensitivity Using a non conductive tool turn the appropriate trim pot counter clockwise to reduce the level until only the 0 is illuminated on the m201 meter If the current signal level is low you need to increase the A D sensitivity by turning the appropri ate trim pot clockwise to increase the level until only the 0 is illuminated on the LED level meter 2 Once all desired calibration adjustments have been made press and hold the INPUT SENS button for approximately 3 seconds This will exit CAL mode and return the A D to normal operation The new settings are now stored until future changes are made 3 Power down the unit disconnect the AC power and reinstall the top cover grace design m201 owner s manual CH2 B VR4 CH2 A VR3 gt ia 9 re HH 8 2 O Bloooooool X Sr LL SEA P1 FD1 CH1 B VR1 figure 3 A D sensitivity trim pot locations CH1 A VR2 Maintenance The model m201 was designed to be maintenance free for many years It is highly unlikely that your unit will require service However there are two adjustments that may need to be made from time to time These procedures can be made by a qualified service technician or at the Grace Design factory PEAK LED ADJUSTMENT PROCEDURE The peak LED threshold levels may b
7. 1 owner s manual Important Safety Information GENERAL e Indoor use only e Ordinary Protection This equipment should not be exposed to dripping or splasing e Avoid placing objects filled with liquids such as vases or glasses on this equipment e Class Equipment grounded type Electrical rating 100 120 220 230 240V 50 60Hz 30W e Mains supply voltage fluctuations are not to exceed 10 of the nominal supply voltage e Pollution Degree 2 e Installation Overvoltage Category Il for transient overvoltages e Maximum Relative Humidity 8096 e Operation temperature range 10 C to 40 C Storage and transportation temperature range 40 C to 70 Maximum altitude 3000m 9843 ft Equipment suitable for continuous operation Weight preamplifier 7 5kg 16 5165 SAFETY MARKING SYMBOLS CAUTION READ ACCOMPANYING DOCUMENTS This symbol located on the equipment and in this manual refers to important instructions Read this manual thoroughly before operating this equipment WARNING ELECTRICAL SHOCK HAZARD This symbol located on the equipment and in this manual indicates the poten tial for electrical shock hazard SERVICE INFORMATION The Grace Design m201 contains no user serviceable components Contact Grace Design for re pair and upgrade information In the event that your Grace Design m201 needs to be returned to the factory contact us for a return authorization number grace design m201 owner s manual Front P
8. A D card is available installed on new m201 s from the factory or as an upgrade to your existing m201 If you need more informa tion about upgrading your m201 with the A D module please feel free to call us at 303 443 7454 INPUT SOURCE SELECT The m201 A D can receive signals from 3 different inputs channels 1 amp 2 from the mic preamplifier section the M S matrix outputs or the external balanced line inputs locat ed on the back panel of the A D module The A D source select switch lower left is used to toggle between the three input source options which are illuminated green directly above in the bezel grace design m201 owner s manual 10 Simply push the button to select the input source you require FS SELECT The 201 A D converter can operate at sampling rates of 44 1 48 88 2 96 176 4 and 192kHz Whether operating on the internal crystal or an external clock source you must select the appropriate sampling rate at which you wish to record The top left switch above the A D bezel la beled FS SELECT is used to toggle between all the available sampling rates Simply push the button to select the sampling rate you require The selected rate will be illuminated green below Selecting OFF puts the A D converter circuitry in low power standby mode with all oscillators off CLOCK SOURCE The m201 A D can be run from the internal crystal an external word clock source or from Avid loopsync The top middle switch labeled CLOCK
9. E AMPLIFIER 1300 20dB 130 CH2OUTA DIGITAL OUTPUTS ADC INPUTS FROM PREAMP CH 1 2 FROM M S OUTPUT LINE IN LEFT AES3 2 x WIDE RANGE PLL rej TOSLINK LINEINRIGHT s Lock PLL i 2 CH SPDIF WORD CLOCK LOOP SYNC IN fo CLOCK OUT INTERNAL CLOCK grace design m201 owner s manual 18 Warranty Information Grace Design warrants all of our products to be free of defective parts and workmanship for a period of five years This warranty period begins at the original date of purchase and is transferable to any person who may subsequently purchase the product during this time This warranty excludes the following conditions normal wear and tear misuse customer negligence accidental damage unauthorized repair or modification cosmetic damage and damage incurred dur ing shipment During the time of this warranty Grace Design will repair or replace at its option any defective parts or repair defective workmanship without charge provided the customer has appropriate proof of purchase and that the product has its original factory serial number Customers within the US are responsible for all inbound freight charges to Grace Design s facility while Grace Design will pay for return freight charges via ground service Customers outside the US must contact their distributor for warranty product return d
10. SOURCE is used to select between these options The selected clock source will be illuminated green below the switch A D MODE The m201 A D is capable of transmitting AES EBU digital audio in single or dual wire modes and in either professional or consumer format The upper left switch selects between these various formats The selected format will be illuminated green below the switch PEAK RESET MODE High resolution 20 segment metering is included with the m201 A D option When A D input signals hit or exceed absolute zero OdBfs the over indicator lights over placed above and below 0 on the meter will illuminate red and remain lit until the peak reset switch is pushed Peak signal levels are indicated by the highest level LED remaining lit The peak indicators can pro grammed to remain lit indefinitely until the reset switch is pressed infinite stay lit for 4 seconds delay or not stay lit at all off These three modes are selected by simply pressing and holding the PEAK RESET MODE switch for approximately 3 seconds which toggles through the three available modes Adjusting A D Converter Sensitivitu The m201 A D converter features two independent A D sensitivity configurations The front panel in terface allows the user to easily switch between these two calibrated settings Each of the two input sensitivity ranges A and B can be configured for one of four standard A D sensitivities The follow ing sections detail th
11. This knob controls the ratio between the Mid and Side signals in an M S recording setup Please see the preamplifier operation section of this manual for complete information regarding this feature standby power switch Connects the mains voltage and turns on the m201When depressed the pushbutton will illumi nate green and the preamplifier will be on When released the preamplifier will be in standby mode Rear Panel Connections CR A C E s IYA2O 1 cane e 3 TOSLINK AES 2 AES 1 LINE IN cirque FUSA EUSA A LEAD FREE M S OUT FY amp e amp OUT LEFT OUT 1 XLR mic input connectors Input connections are made via female XLR con nectors with pin 2 positive pin 3 negative and pin 1 ground 48V phantom power is supplied on pins 2 and 3 2 XLR output connectors Parallel XLR outputs are provided for sending line signals to two seperate recording devices or mix ers Output connections are made via male XLR connectors with pin 2 positive pin 3 negative and pin 1 ground 3 XLR outputs are provided for sending M S sig nals independently of the standard line outputs Output connections are made via male XLR con nectors with pin 2 positive pin 3 negative and pin 1 ground 4 IEC AC power input Accomodates the included 3 prong AC cable Connect to grounded outlet only 5 130V DPA microphone inputs optional Accomodates 130V DPAO microphones via 4
12. anel Controls x ribbon ib 50 erheen l N e130V BO INPUT MODE 48V o OF 24 position gold contact gain switch Each gain control has 24 positions and adjusts the voltage gain from 18dB to 64dB in 2dB steps In ribbon mode the gain range is 28dB to 74dB in 2 steps bi color LED peak indicator The LED peak indicator which monitors the output signal level turns green at 14dB and switches to red at 16dB 12dB before clipping The threshold level for peak indication is adjustable on each chan nel see the calibration section of this manual input mode switch The input mode switch is used to select between the various types of inputs available with the m201 including standard 48V ribbon mic mode HI Z or the optional 130V DPA inputs Refer to the m201 block diagram at the end of this manual for signal routing details 48V phantom power switch The phantom power switch labeled 48V connects the 48V power supply to pins 2 and 3 on the XLR input connector This switch illuminates red It should be noted that the LED in this switch actually monitors the phantom power voltage at the input With no microphone connected the LED will contin ue to illuminate for approximately 10 seconds after the phantom power is turned off as the filter capaci tors discharge As well even if the phantom power is switched off the LED will illuminate if voltage is being fed
13. carry the amplified signal from the DI inputs There is no 48V phantom available on this input The phase reverse switch is active and the gain range of this input is 2dB to 44dB 20dB less than the 48V input so therefor the 20dB pad is not available This connector is balanced with the Tip positive Ring negative and Sleeve ground ribbon This setting puts the m201 into ribbon mic mode which is described in detail below Use this input for ribbon microphones or any application where an additional 10dB of gain may be re quired In this position the main XLR mic inputs are feeding the preamplifier and the dual XLR out puts are active 130V This setting activates the optional 130V input module for DPA microphones If the 130V input grace design m201 owner s manual option is present this selection will deactivate the standard XLR inputs and enable the dedicated 4 pin 130V XLR inputs In this mode the 48V pushbutton switch will turn on the 130V power supply Phase reverse and 20dB pad are available in this mode The dual balanced XLR outputs carry the output signal Note this option is no longer available SETTING THE GAIN First turn the gain control fully counter clockwise and check that the 48V phantom power is off Connect a microphone and then turn on the phantom power if required When sending a signal to a recorder converter or interface that has fixed input levels simply increase the gain until the opti mum recording level
14. e A Range B can be calibrated for any setting between 18dBu OdBFS and 24dBu OdBFS 0 2dB 5Hz 21kHz 5Hz 23kHz 5Hz 41kHz 5Hz 45kHz 5Hz 54kHz 5Hz 59kHz gt 115dB gt 117dB lt 0 00026 112dB 3dB 22kHz 24kHz 44kHz 48kHz 72 5kHz 79kHz 16dB or 24dB 2dB trim gt 65dB gt 80dB gt 60dB lt 100dB 0 0008 lt 120dB 13 Fs 44 1 48 88 2 96 176 4 192 40 1kHz 207kHz 8 at each sample rate 250ppm 350 400ppm typical lt 60ps RMS lt 40ps RMS 800Hz 10Hz 22dBu 0dBFS 18dB headroom 18dBu 0dBFS 14dB headroom grace design m201 owner s manual 17 Signal Flow Diagram INPUTS GRACE DESIGN ANALOG OUTPUTS RIBBON 1008 gt 48V gt 20dB gt 48 m201 SIGNAL FLOW DIAGRAM EX gt gt T HI Z INPUT MICROPHONE AMPLIFIER BALANCED OUTPUT DRIVERS ws outputs gt 130V gt 20dB gt i M S SUMMING LEFT OUT SIDE AMPLIFIER M S WIDTH RIBBON 10dB i gt 48V gt 20dB gt 48 M S DIFFERENCE LL RIGHT OUT E AMPLIFIER ANALOG OUTPUTS gt Q gt 4 gt w BALANCED POUR HI Z INPUT AMP MICROPHON
15. e adjusted to a user defined operating level This circuit is set at the factory with the green threshold at 14dBu and the red threshold at 16dBu The relationship between the two thresholds is fixed The procedure for adjusting the green red threshold follows EQUIPMENT NEEDED e Sine wave audio signal generator or oscillator output from a mixing console Audio level meter or an RMS Volt meter with dBu or dBm scales Plastic alignment tool small screwdriver Appropriate interconnect cables 2 phillips head screwdriver PROCEDURE 1 With the power off remove the eight phillips head screws from the top cover and remove it from the 201 12 grace design m201 owner s manual Set all of the gain controls to the 30dB position Connect the audio generator to the input of channel 1 Set the generator output level to approximately 20dBu 1KHz If the generator has an unbalanced output refer to figure 2 below for termination information Connect the level meter to the output of channel 1 If the level meter has an unbalanced input refer to lt figure 1 gt for unbalanced output termination information Apply power to the generator preamplifier then the level meter 9 Adjust the generator output level so that the preamplifier output level is at the desired red thresh old If the proper level can t be reached adjust the preamplifier gain control 10 Locate VR2A VR2B for channel 2 see lt figure 3 gt on the cha
16. e operation and calibration of this feature SELECTING THE A D SENSITIVITY From the m201 front panel interface pressing and releasing the INPUT SENS push button toggles the selected A D input sensitivity The currently selected range A or B is illuminated CALIBRATING THE A D SENSITIVITY The m201 ships with the following two default sensitivity cali brations A 22dBu OdBFS 18dB Headroom B 18dBu OdBFS 14dB Headroom Internal trim controls allow you to reconfigure either or both of the sensitivity levels grace design m201 owner s manual Four standard sensitivities are supported in the 201 A D converter 18dBu OdBFS 14dB Head room 20dBu OdBFS 16dB Headroom 22dBu OdBFS 18dB Headroom 24dBu OdBFS 20dB Headroom The front panel interface features a calibration mode that allows precise adjustment of the A D sensi tivity To recalibrate one or both of the input sensitivity configurations simply do the following 1 Disconnect AC power from the m201 2 Remove the 8 top cover screws using a 2 Phillips screwdriver Lift the top cover off the unit and set it aside 3 Reconnect AC power to the m201 and turn it on 4 Connect a signal generator to the A D LINE inputs Set the signal generator output to 4dBu 1kHz 1 29V rms 5 Turnon the m201 A D converter and select LINE as the A D input source 6 enter CAL mode press and hold the INPUT SENS button for approximately 3 seconds The nor mal op
17. ead screwdriver PROCEDURE 1 Remove the 8 phillips head screws from the top lid but leave the lid in place 2 Set all of the preamplifier gain controls to maximum 3 Turn on the m201 preamplifier and allow to warm up for at least 45 minutes 4 Remove the top lid and locate the DC offset test points TP1A and TP2A see figure 4 below Place the Volt meter probes into these holes 5 Locate DC offset potentiometer VR1A VR1B for channel 2 and rotate it for a reading of 0 000VDC 0 003V 6 Theinput offset does drift with temperature and having the lid off will allow the circuitry to cool It is advisable to replace the lid and let the preamplifier warm up again about 20 minutes and then re check your adjustments grace design m201 owner s manual o _VR2B mim d m mumumum NITE 9 mmmmmii ma E RIMIS Qu mat m L mm mm iF mmm tn zar m mm mmm nooooo a IH mm Eleloeoe Em RN Hu a 9oooo X ooo m 1111 T rm mum mE k Will gg mim 000 mmmm Hmm O ajn m m Gs lel TTT a E mu mi m eae Ea un mm Hi ama M mm oo
18. eration displays will extinguish and the CAL indicator will begin flashing indicating CAL mode is active The current input sensitivity range A or B will be illuminated along with that range s current sensitivity calibration shown as dB Headroom in the bottom left of the meter display 7 Press and release the INPUT SENS button to select the range A or B that you wish to calibrate 8 Press and release the A D SOURCE button to scroll through the 4 available sensitivities until the desired setting is illuminated In calibration mode the digital audio meter is configured such that the 0 position is the target sensitivity level The meter then indicates the current signal level versus this target sensitivity The meter will display a window centered around the target sensitivity with a 0 4dB width in 0 1dB increments When the sensitivity adjustment on the A D converter is calibrated for the selected set ting only the 0 LED will be illuminated If the signal level is high the 0 indicator will be illuminated along with the error in 0 1dB increments to the right of 0 If the signal level is low the 0 indicator will be illuminated along with the error in 0 1dB increments to the left of 0 On the m201 A D module trim pots are used to adjust the A and B ranges for each channel Each of these are labeled on the A D module circuit board lt figure 3 gt 1 Locate the appropriate trimmer for the channel you wish
19. erful Technique for Working in Ste This paper No 1792 is available from the Audio Engineering Society web page www aes org The Optional A D Converter Features 1 2 3 FS SELECT CLOCK SOURCE ADC MODE 60 50 40 32 28 24 20 18 16 14 12 10 8 6 5 4 3 2 14 16 18 20 lt 0 4 0 3 0 2 0 4 0 0 1 02 0 3 0 4 gt HEADROOM dB CAL LEVEL 9 B 172220 1 A D converter ADC SOURCE INPUT SENS PEAK RESET MODE e Cu a 8 7 6 5 1 FS SELECT this switch is used to toggle through the available ADC sampling rates 2 CLOCK SOURCE this switch is used to select the ADC clock source 3 ADCMODE this switch is used to select single or dual wire AES and switch between either professional or consumer fomat 4 OVER lights illuminate when the ADC has been overloaded and remain lit until the PEAK RESET swich is pushed 5 PEAKRESET MODE This switch is used to clear peaks on the 20 segment led meter and to select how the meters display peak information 6 INPUT SENSITIVITY CALIBRATION SCALE 7 INPUT SENS selects between the two programmable ADC input sensitivity settings 8 ADC SOURCE selects the input source which feeds the ADC module 9 1 ADC headroom indicator 0 20 segment LED level meter Operating The A D Converter Module If you have purchased the optional A D converter module for your m201 the following section will help you become familiar with its features and its operation The m201
20. ermodulation Distortion 40dB gain 25dBu out SMPTE DIN 1 1 50Hz 7kHz lt 0020 SMPTE DIN 4 1 50Hz 7kHz lt 0030 Noise Referred to Input 60dB gain 500 source 130dB 60dB gain 1500 source 127dB 60dB gain 6000 source 123dB Phase Deviation 100Hz 20kHz 40dB gain 3 Crosstalk Any Channel 40dB gain 1kHz 125dB Any Channel 40dB gain 10kHz 115dB CMRR 60dB gain 3 5Vcm 1kHz gt 70dB 60dB gain 3 5Vcm 10kHz gt 70dB Maximum Output Level 1kHz 100 load 28dBu Impedance Input 81000 Input ribbon mode 20kQ Output 1900 Peak Led Meter Green threshold 14dBu Red threshold 16dBu Weight and Dimensions dimensions 2U 19 rack mount x 10 deep weight 16 5165 7 5kg Power Consumption 100 120 230 240V 50 60Hz 20 Watts Max 16 grace design m201 owner s manual A D module specifications line input Dynamic range 20Hz 20kHz A weighting THD N 1kHz 1dBFS 20Hz 22kHz Frequency response 44 1kHz Fs 48kHz Fs 88 2kHz Fs 96kHz Fs 176 4kHz Fs 192kHz Fs Full scale input level CMRR 60Hz 1kHz 10kHz IMD SMPTE 4 1 60Hz 7kHz 3dBFS Interchannel crosstalk Group delay 44 1 48kHz Sample rates internal crystal kHz External Clock Lock Range Wide lock mode s Lock mode Intrinsic Jitter 200Hz 20kHz BW Wide lock mode s Lock mode Jitter Rejection Corner Frequency Wide lock mode 3dB 12dB octave s Lock mode 3dB 12dB octave A D sensitivity Rang
21. etails In order for Grace Design to provide efficient and timely warranty service it is important that you mail the completed warranty registration card enclosed with all of our products within 10 days of the original date of purchase You may also register your product directly with Grace Design by telephone 303 823 8100 Monday Friday 9 00am to 5 00pm MST or you can register your product online at www gracedesign com This warranty is in lieu of all other warranties whether written expressed or implied INCLUDING ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE In no event will Grace Design be liable for lost profits or any other incidental consequential or Exemplary damages even if Grace Design is aware of the possibility of such damages In no event will Grace Design s liability exceed the purchase price of the product This warranty gives the customer specific legal rights The customer may also have other rights which vary from state to state Some states do not allow limitations on implied warranties or consequential damages so some of the limitations of the above may not apply to a particular customer grace design m201 owner s manual Manual Revisions Revision Page Cms in Be s changed vatage range and power specifications 5 4 Power switch description changed to standby switch 04 26 2007 _ mbg K S
22. from an external source i e when us ing a direct split in a remote recording application Also the 48V switch is used to activate the 130V DPA mic power if this option is installed grace design m201 owner s manual e meo1 microphone preamplifier GRACE DESIGN USA polarity reversal switch The polarity reverse switch reverses the absolute phase of the music signal at the input of the pream plifier The switch illuminates green and provides power for a sealed gold contact relay located on the preamplifier circuit board This eliminates signal wiring to the front panel and switch contact perfor mance problems The polarity reverse function is active for all input connectors 20dB pad switch The 20dB attenuator switch attenuates the input signal 20dB The switch illuminates amber when engaged Like the phase reverse switch this switch controls a sealed gold contact relay on the pream plifier circuit board With the 20 switch engaged the effective gain range becomes 2dB to 44dB The 20dB attenuator is active for 48V Phantom ribbon and optional DPA inputs It does not affect the HI Z inputs HI Z input This 1 4 inch TRS input is active when the input mode switch is in the HI Z position Suitable for any high impedance source such as bass guitar acoustic guitar electric guitar keyboards etc This input is can be used balanced with a TRS connector or un balanced with a TS connector M S width control
23. is in the power input module Replace the fuses with the proper value selected from lt figure 2 gt below Be sure to use a time delay fuse with a 250V rating CAM SETTING LINE VOLTAGE FUSE VALUE 100V 100V 250V T 500mA L 120V 120V 250V T 500mA L 230V 220V 250V T 315mA 230V 230V 250V T 315mA L 240V 240V 250V T 315mA L lt figure 2 fuse value table gt Prearnplifier Operation TURNING THE POWER ON The power switch is located on the m201 front panel Pushing the power switch in turns the mains power on switch illuminates green Pushing the power switch again turns the mains power off USING THE INPUT MODE SELECTOR SWITCH The input mode switch to the right of the gain control provides a convenient way for the user to se lect between the various types of inputs the m201 can accommodate The following is an overview of the four settings 48V This setting should be selected for all general recording applications with most microphone types In this position the main XLR mic inputs are feeding the preamplifier and the dual XLR out puts are active Proceed with the setting the gain discussion below HI Z This setting is used to select the front panel mounted 1 4 instrument DI inputs These inputs can accommodate a wide variety of high impedance input sources including bass guitar keyboards electric guitars etc In this mode the rear panel XLR inputs are not active while the dual balanced XLR outputs
24. nnel 1 audio circuit board and adjust until the peak LED is between green and red The color should appear amber when the setting is correct Repeat this procedure for channel 2 11 If it is desired to calibrate the peak indicator to a specific converter recorder input level simply connect the output of the preamplifer to the converter recorder Adjust the signal generator so that the desired peak level is indicated on the recorder and then adjust VR1 until the peak LED is between green and red D P WN INPUT OFFSET ADJUSTMENT The input amplifiers in the m201 are ultra precision laser trimmed devices which have a very low input offset However even the smallest differential offset at the input can result in an audible click when the gain control is turned It should be noted that this type of click will be audible when no signal is present With no signal present there is no signal amplitude to be changed unless input off set is present This procedure nulls the input offset and minimizes the clicking sound with no signal present In contrast there will almost always be an audible click if turning the gain control while a signal is present This is because the gain control being a stepped control will make an instanta neous change in amplitude when turned which creates a transient signal EQUIPMENT NEEDED DC Volt meter with at least 1mV sensitivity Plastic alignment tool or a small screwdriver 2 phillips h
25. ooo m HH Hm REN ooo He am nn mia P2A TP1 a m o 5 5 m x 2 Sam oE E Cam p Oe x LARA c c gt gt vi DA OA A eee IL T I LIS urIr FRONT PANEL lt figure 4 offset test point and peak LED adjust trim pots gt grace design m201 owner s manual 14 CLEANING Your m201 preamplifier chassis is constructed out of high quality stainless steel Under normal cir cumstances virtually no maintenance is required to keep the unit looking shiny and new However if your unit becomes smudged or dirty here are some cleaning tips We recommend using either Pledge furniture polish or Zep brand stainless steel cleaner available at the hardware store Apply cleaner to clean dry lint free cloth and gently wipe all stainless surfaces taking care not to allow the cleaning product to build up around the panel switches or knobs grace design m201 owner s manual Specifications preamplifier specifications without A D converter Frequency Response 40dB gain 0 2dB 500 source 18Hz 65kHz 40dB gain 3dB 500 source 4 5Hz 350kHz THD N 20dB gain 25dBu out 1kHz lt 0008 40dB gain 25dBu out 1kHz lt 0009 60dB gain 25dBu out 1kHz lt 0070 Int
26. source from the mic input connector to the front panel TRS jack The input impedance of the instrument input is 2M Ohm balanced and 1M Ohm unbalanced which is ideal for inserting high impedance sources such as guitars with passive pickups as well as any instrument with a high level output Wiring of the HI Z jack is Tip positive Ring negative and Sleeve ground Please note that the gain range of the preamplifier when using the instrument input is 2dB to 48dB in 2dB steps Pouier Connections A standard three prong AC power cable is included with the m201 For safety the power supply cord must be connected to a grounded outlet The Disconnect Device for the m201 is the Mains plug or the Appliance Cou pler on the power supply cord The Disconnect Device must remain acces sible and operable CHECK LINE VOLTAGE SETTINGS Your m201 has been set from the factory to operate at the voltage required for your part of the world However it s important to double check this in order to ensure no damage will come to the unit if power is applied while the setting is incorrect AC input voltage settings can be adjusted for 100V 120V 220V 230V and 240V operation at 50 grace design m201 owner s manual 60Hz From the rear of the m201 open the trap door next to the IEC power inlet with a small screw driver Carefully pull the voltage select cam straight out and then insert with the desired voltage showing Do not try to rotate the cam while it
Download Pdf Manuals
Related Search