AMP2-DA/AVU and AMP2-DA/APP CONTENTS User Manual
Contents
1. Distortion Electrical Less than 0 15 at any level below Optional XLR connectors instead of BNC may be input threshold specified for the AES inputs at the time of order Distortion Acoustic 6 or less at worst case frequencies above 120 Hz including cabinet resonance typically less than 1 5 Input Overload 26 dBv balanced Converted Analog Out S N gt 90dB Converted Analog Out THD lt 0 008 Magnetic Shielding lt 0 8 Gauss any adjacent surface Note See page 21 for level meter specifications Power Consumption Average Maximum AC Mains Input 100 240VAC 50 60 Hz Universal Audio Response Curve 10 20 50 100 200 500 1k 2k 5k 10k 20k Hz Typical 1 6 Octave Audio Response Curve Units are designed to meet at time of manufacture all currently applicable product safety and EMC requirements such as those of CE 0 dbV ref 0 775V RMS Features and specifications subject to improvement without notice 2004 Wohler Technologies Inc ALL rights reserved 5 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 1 Features Specs and Installation Installation Mounting The unit should be mounted where convenient for operating persons ideally at approximately ear eye level for best high frequency response and visual observation of the level meters Its superior magnetic shielding eliminates concerns ab2. configured for unbalanced 75 Q connections Either of the two inputs is selected by setting the AES Source Select Switch Item 4 page 8 on the front panel to 1 or 2 Note that the unit will monitor the selected AES source only when the Analog Digital Source Select Switch Item 3 page 8 is set to DIGITAL res 1 ren 1 rem 1 Optional balanced inputs on female XLR connectors may be specified for the AES inputs in lieu of BNC connectors AES Input Level Gain Calibration DIP Switch Input Level Gain Calibration the analog level which corresponds to a given digital input value is settable via this DIP switch The factory setting is 4 dB analog 20 dBFS digital See the silk screened chart on the rear panel or the diagram below for settings Digital Gain Calibration HE 8 dB 20 dBFS Bu 4 dB 20 dBFS lal 6 dB 9 dBFS BE o aB 18 dBFS Continued 12 2004 Wohler Technologies Inc ALL rights reserved Section 2 Operation AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A DIGITAL GAIN CALIB CH A L CH B R wy Wohler echnologies Inc 713 GRANDVIEW DRIVE SOUTH_SAN FRANCISCO CA 94080 Tel 650 589 5676 Fax 650 589 1355 Rear Panel Features 100 240 VAC FAN N AMP2 DA 50 60 Hz 253935 2b 2004 Wohler Technologies Inc ALL rights reserved Figure AMP2 DA AVU and AMP
3. e Two selectable AES EBU inputs on unbalanced BNC connectors e Power indication LED 4 2004 Wohler Technologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 1 Features Specs and Installation Applications The AMP2 DA AVU and AMP2 DA APP are ideally suited for use in VTR bays mobile production vehicles teleconferencing installations multimedia systems satellite links and cable TV facilities and on air radio studios Designed and manufactured in the U S both models are backed by a strong warranty and a satisfaction guaranteed return policy General Specifications Digital AES Specifications Input Connectors AES BNC Analog XLR AES termination 75Q ohm removable unbalanced Analog Input Impedance XLR 70K Q balanced AE li te 2 48 kHz auto select Digital Input Impedance BNC 750 unbalanced PANOA i es Peak Acoustic Out 2 ft 104 dB SPL Die ener alli al Power Output Dto A gain calibration DIP switch selectable RMS Each Side 412 14 W transient 10 W continuous dB dBFS 0 18 6 9 4 20 8 20 RMS Bass 4Q 35 W transient 25 W continuous Frequency Response 80 Hz 16 kHz 5 dB Physical Specifications Sixth Octave 10 dB 40 Hz 20 kHZ Input Level for Maximum Output Volume Full On 0 dBv balanced 10 dB unbalanced Hum and Noise analog Better than 68 dB below full output Dimensions HxWxD 3 5x 19x12 inches 89 x 483 x 305 mm
4. which are the nominal ones If any of the drivers speakers are replaced 1t may be helpful to change some of these components to achieve maximum flatness of response The operating threshold of the woofer limiter is critical to both satisfactory reproduction of musical transients and preventing damage to or destruction of the speaker itself The side speaker output limiter circuits are similarly important though not as critically adjusted The woofer power amps are arranged in a bridge configuration care must be taken to avoid letting EITHER speaker terminal contact the chassis common OR THE GROUNDED LEAD OF ANY TEST EQUIPMENT so as not to short out the power amps The side speaker outputs are single ended so these precautions are not necessary for them 18 02004 Wohler Technologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 3 Technical Information AES to Analog Converter Module PCB 919117 There are four primary and three ancillary sections comprising the 919117 PCB AES EBU digital to analog converter 1 Input source selection 2 audio data extraction 3 Digital to analog conversion 4 Analog buffer output amplifiers 5 Power suppy Reset and Error indication Input Source Selection 1C13 Each of the two selectable signal inputs are transformer coupled to the inputs of a one of two active buffer switch IC13 The output of this switch 1s applied to the receiver stage
5. power and an operation voltage is present Continued CO 2004 Wohler Technologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation S3 9O01ONH93L YTIHOM TWLIDIO aounos DOTVNV lt OJ o an er SS TANVd HOLINOW olan ILIA mv vazamv B Figure 2a Front Panel Features 2004 Wohler Technologies Inc ALL rights reserved 9 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation Front Panel Features Continued Phase Indication LEDs These three LEDs indicate the instantaneous and average phase polarity conditions between the two signals in the channel pair or downmix assigned to the left and right speaker channels The two smaller LEDs labeled FAST show instantaneous phase relationships in the signal The larger LED labeled AVG will indicate the average phase condition Indication is as follows The left FAST LED glows or blinks GREEN for in phase signals The right FAST LED glows or blinks AMBER for out of phase signals The large AVG LED indicates the average phase condition by glowing GREEN for in phase signals or RED for out of phase signals In general observing the AVG LED alone is sufficient for proper phase monitoring While it is normal for stereo signals to contain some intermittant instantaneous out of phase and in phase conditions FAST LEDs a steady RED glow of the AVG LE
6. used to set the termination characteristics for the AES inputs and to set the error type indicated by the AES Status LED Item 5 page 8 Note Section 3 of the DIP module is not used AES Input Termination In the event that either of the two AES input channels is fed to downstream equipment the associated DIP switch section section 1 IN 1 and section 3 IN 2 must be placed in the UP Unterminated position If there is no downstream equipment connected then the associated DIP switch section must be placed in the DOWN Terminated position See below left for a diagram of termination settings Error Indication Type DIP switch section 1 may be set to allow the AES Status LED to indicate either reception and data errors or to indicate reception errors only See the diagram below right for settings AES Error Indication Settings AES Input 1 Termination AES Input 2 Termination Error Fault Type Red LED Reception Reception and Error Only Data Error ene 1 fe ERROR ee Unterminated Terminated Unterminated Terminated term 1 rer 1 TERM 1 TERM 2 TERM 2 TERM 2 teem 2 TERM 2 TERM 2 x x x x x x O00 0000 008 0000 WOU n000 1234 1234 1234 1234 1234 1234 Note Section 3 of DIP module is not functional Note Section 3 of DIP module is non functional C AES Unbalanced BNC Input Connectors IN 1 and IN 2 These two AES inputs on female BNC connectors IN 1 and IN 2 are meant to receive standard AES signals and are
7. 2 DA APP User Manual P N 821584 Rev A Section 2 Operation Rear Panel Features Continued E Selected Analog Output Connectors These two 3 pin male XLR connectors are analog outputs of the selected source as assigned to the left and right speakers The left connector outputs the left channel Channel A and the right outputs the right channel Channel B Both connectors are configured for low impedance connections and the output signals are not affected by the volume balance controls or headphone mute For XLR pinout information see the diagram below Pin 2 Pin 1 Pin 1 Pin 2 High Gnd Gnd High Shield Shield Pin 3 Pin 3 Low Low Female XLR Pinout Male XLR Pinout 14 Analog Input Connectors LEFT A and RIGHT B These two 3 pin female XLR connectors Left and Right accept standard analog audio signals and are configured for balanced 70K Q connections For XLR connector pin out information see the diagram under Item E Note that the analog inputs are monitored only when the Analog Digital Source Select Switch Item 3 page 8 is set to ANALOG 2004 Wohler Technologies Inc ALL rights reserved Section 2 Operation AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A DIGITAL INTERNAL POWER GAIN CALIB SUPPLY APPROVED BY UNDERWRITERS LABS SERIAL SEE POWER SUPPLY NUMBER els LABEL ON SIDE CH A L CH B R W Wohler Technologies Inc 713 GRANDVIEW DRIVE SOUTH SAN FRANCIS
8. 3 pin female XLR connectors and are configured for 70K Q balanced connections Care should be exercised to avoid mismatched cable types and other similar causes of undesired reflections in RF signal systems If severe enough such reflections can result in corruption of the digital datastream AC Power The unit s AC mains connection is via a standard IEC inlet with safety ground connected directly to the unit s chassis The universal AC input 100 240VAC 50 60Hz switching power supply is a self resetting sealed type with automatic over voltage and over current shutdown There is no user replaceable fuse in either the primary or secondary circuit 6 2004 Wohler Technologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Operation Front Panel Features Rear Panel Features Audio Amplifier and Speaker Configuration Balance Control Characteristics 2004 Wohler Technologies Inc ALL rights reserved 7 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation Front Panel Features Please refer to Figure 2a on the facing page to familiarize yourself with the front panel features ofthe AMP2 DA AVU and AMP2 DA APP units The following sections describe these features and are referenced by number to Figure 2a 4 Speakers The monitor features two mid range speakers left and right and one woofer speaker Two amplifier driver combinations handle midrange and high frequency informat
9. 39 a ezoe16 waa y uy Bojeuy e HE goana W V I J9J9 N 9497 l l jeoueyooyy l ejes 7vL91A 29 moS Q d v lo m m me m m ell E g n Bojeuy Y sounos eybig AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A 2004 Wohler Technologies Inc ALL rights reserved c free UOEDIPU v80616 DOTVNV a VINO Bojeuy eseud y ad Sl Mas En ce eee eT WV PRA y 11616 god Ndu Na3 s3w A Jayeeds y eta J i ppajes eounog dinos Hr indul Savy EEE WY ly l SJOJ93UUOD 7 F y O E zur sav ne l gztequn Jayesd OL eae asa Sra eRe wv en Big Jb ul sav J9J00M l Y i m7 l UU Jeyeeds r E z 9uueyo l peg A ya7 1 l aes seas l joie Q avanos JEVOIQ DOjeuyy 6 ae oe l e4bIg jaued 1eubis SAV L 1e9y OUIN O A 5 weibeig 490 9 J99UU0949JU ddY VYA ZdWY pue NAV YA ZdINY AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A NOTE PCB layout and schematic support documentation is available upon request Wohler Technologies Inc 31055 Huntwood Avenue Hayward CA 94544 Phone 510 870 0810 Fax 510 870 0811 US Toll Free 1 888 596 4537 www wohler com support wohler com 02004 Wohler Technologies Inc ALL rights reserved 23 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A WWohler Wohler Technologies Inc 31055 Huntwood Avenue Hayward CA 94544 Phone 510 870 0810 Fax 510 870 0811 US Toll Fre
10. A AVU and AMP2 DA APP are monitors capable of audibly monitoring two source channels through a stereo speaker system while simultaneously visually monitoring the two channels on two high quality mechanical audio level meters The AMP2 DA AVU model features mechanical meters with VU ballistic characteristics and the AMP2 DA APP model features these meters with PPM ballistic characteristics Either digital AES or analog audio signal sources may be selected for monitoring via a front panel toggle switch The user may also select between two AES inputs on the rear panel with a front panel toggle switch AES signal status is indicated by a bi color red green LED Wohler Technologies proprietary three LED stereo phase indication feature allows visual monitoring of phase relationships of the signals assigned to the left and right speaker channels Other features include volume and balance controls power indication LED and headphone output The rear panel for these monitors include two selectable AES inputs on BNC connectors standard two analog inputs on female XLR connectors and a stereo analog output of the left and right speaker channels on two balanced male XLR connectors Optional balanced XLR connectors instead ofunbalanced BNC connectors may be specified for the AES inputs at the time of order All AMP2 Series units contain three audiophile quality drivers and three power amplifiers two amplifiers and two speakers that reproduce midrange and
11. CO CA 94080 Tel 650 589 5676 Fax 650 589 1355 Rear Panel Features 100 240 VAC Z AMP2 DA 50 60 Hz SOURCE 253335 2b 2004 Wohler Technologies Inc ALL rights reserved O Figure AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation Audio Amplifier and Speaker Configuration General Description All models in the AMP Series contain high performance transducers speakers driven by three power amplifiers two amplifier driver combinations handle midrange and high frequency information in the left and right stereo speaker channels while the third amplifier channel sums the left and right channel information be ow the 500 Hz crossover point in the woofer bass speaker s Note that the woofer channel is NOT a dedicated LFE subwoofer or Center channel Speaker Configuration All AMP2 2U products are configured with two speaker channels left and right to reproduce midrange and high range audio frequencies in stereo and one woofer speaker channel to reproduce the summed combined low range audio frequencies from the left and right speaker input channels See below for a simplified diagram of the AMP2 audio amplifier speaker configuration am H Left Left Speaker Speaker Channel EQ Limiter High Pass Amplifier A a S Volume ss Lo Freq Woofer Woofer Speaker alance Amplifier Speak Ch l VEO peaker annel Limiter Sum Low Pass Input B Right Righ
12. D indicates an out of phase alarm condition Balance Control This control changes the volume balance between the left and right speaker channels Note that this control attenuates the signal from the source so that the left and right bass frequencies summed together and reproduced in the woofer channel will respond to balance adjustments in tandem with the left and right speaker channels See page 16 for more information concerning the balance control characteristics 2004 Wohler Technologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation S3 9O1ONHI3L YTTHOM 5 N Y TVLIDIO E O TANYd HOLINOW olany 1VLIDIO WY Va 7dNV Figure 2a Front Panel Features 2004 Wohler Technologies Inc ALL rights reserved 11 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation Rear Panel Features Please refer to Figure 2b on the facing page to familiarize yourself with the rear panel features of the AMP2 DA AVU and AMP2 DA APP unit The following sections describe these features and are referenced by letter to Figure 2b Power Connector Attach a standard IEC 320 power cord between this connector and mains power 100 250VAC 50 60 Hz The front panel Power LED Item 8 page 8 will glow GREEN to indicate operating voltages are present AES Input Termination and Error Indication Type DIP Switch This 4 position DIP switch module is
13. WWohler AMP2 DA AVU and AMP2 DA APP 2U Digital Audio Speaker Monitor With Two Selectable AES Inputs on BNC Two Analog Inputs on XLR Two Selected Analog Stereo Outputs on XLR Two Mechanical VU AVU or PPM APP Level Meters and Phase Indication Document P N 821584 Rev A User Manual CONTENTS Title and Contents Introduction Section 1 Features Specs and Installation Description and Features Applications and Specifications Installation Section 2 Operation Front Panel Features Rear Panel Features Audio Amplifier and Speaker Configuration Balance Control Characteristics Section 3 Technical Information General Technical Observations AES to Analog Converter PCB 919117 AES Mute On Error Jumper Location 919117 PCB PPM Meter Specifications and Level Threshold Settings VU Meter Specifications and Level Threshold Adjustment AMP2 DA AVU and AMP2 DA APP Interconnect Block Diagram ECO 2551 08 13 04 Important Safety Instructions 1 Read these instructions 2 Keep these instructions 3 Heed all warnings 4 Follow all instructions 5 Do not use this apparatus near water 6 Clean only with dry cloth 7 Do not block any ventilation openings Install in accordance with the manufacturer s instructions 8 Donotinstall near any heat source such as radiators heat registers stoves or other apparatus including amplifiers that produce heat 9 Donot defeat the safety purpose of the polarized or gr
14. chnologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Technical Information General Technical Observations AES to Analog Converter Module PCB 919117 AES Mute On Error Jumper Location 919117 PPM Level Meter Specifications and Level Threshold Settings VU Level Meter Specifications and Level Threshold Adjustment AMP2 DA AVU and AMP2 DA APP Interconnect Block Diagram 02004 Wohler Technologies Inc ALL rights reserved 17 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 3 Technical Information General Technical Observations General Mechanical Observations Elimination of cabinet and component sympathetic vibrations resonances requires considerable attention to mechanical details Because of this and the physical constraints of the speaker s acoustic enclosures even minor changes to any of the mechanical details of the unit can seriously impair its acoustic performance This especially applies to the speaker baffles If mechanical work on the unit is necessary be sure to make adequate notes to permit accurate reassembly Unfortunately the unusual and wholly proprietary method of magnetic shielding is usually degraded slightly by any disassembly of the unit except removal of the rear panel Almost any maintenance or repair will require removal of the cover If an immediately adjacent video monitor shows magnetic interference after reassembly of the unit it must be returned to t
15. e 1 888 596 4537 www wohler com support wohler com 24 02004 Wohler Technologies Inc ALL rights reserved
16. eception of data or no data stream at all A DIP switch on the rear panel Item B page 12 may be set to allow the AES Status LED to indicate reception and data errors or to indicate reception errors only 2004 Wohler Technologies Inc ALL rights reserved 19 Section 3 Technical InformationMute On AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A AES Mute On Error Jumper Location 919117 193135 8 194NOS SAV Installing a jumper at H12 will mute the audio if errors are detected See Item 5 page 8 for more information wee EI SC E Po zar E E J lisas a x 5 i Lea oH va AE Gs pene Ela y Ni w O O TEF apg cae Fra rag Qe OUT q BL oo OE J En d Ela Ayet 919117 AES to el Converter Module PCB 2004 Wohler Technologies Inc ALL rights reserved 20 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 3 Technical Information PPM Level Meter Specifications and Level Threshold Settings The two one per meter Level Threshold DIP switches in the APP PPM unit are only accessible by removal ofthe top cover Each DIP switch is physically located on the inside front panel above the level meter to which it is dedicated Each meter can be independently set with a possibility of four settings 6 0 4 or 8 dBv Factory setting is 4 dBv See the diagram below for DIP switch settings APP PPM Meter Driver PCB 919028 Level Thresho
17. gital Source Select Switch Item 3 must be set to DIGITAL AES Status LED This bi color GREEN RED LED indicates the status of the selected AES input signal 1 or 2 and functions regardless of whether the analog or AES inputs are selected for monitoring LED indication is as follows e GREEN a valid AES EBU digital datastream is being received e RED there are errors in signal reception and or data errors if the data has been tagged as inappropriate for conversion to analog by having the validity bit set Note The AES Termination and Error Indication Type DIP switch module on the rear panel Item B page 12 is used to set this LED to indicate either reception and data errors or to indicate reception errors only An optional feature of the AES signal error detection is the ability to mute the audio when errors are detected in the AES signal To enable this feature a jumper is placed at H12 of the 919117 PCB See page 20 for location of H12 on the 919117 PCB Headphone Jack This jack accepts a standard 1 4 phone type stereo plug Select the headphone audio sources as you would for the internal speakers When you plug in headphones the speakers will mute Volume Control This controls the loudness of the audio reproduced by the internal speakers or connected headphone Clock wise rotation of this control increases the loudness of the monitored audio Power LED This LED glows GREEN to indicate the unit is connected to mains
18. he factory to restore the shielding completely General Audio Circuitry Observations Since a single sided power supply is used all amplifier sections are biased with a 1 2 supply reference so all opamp signal terminals on the main board should have a DC level of 12V 0 7V Signal inputs to the main audio board from any of the input select circuits are via the balanced input stage in lieu of the XLR analog inputs on the basic unit Signal feed points for level meters and the phase indicator are immediately after the input stage and before the volume control section The signal pick off for the headphones is after the volume and balance controls Speaker muting is controlled by circuitry that senses connection of headphones to the jack The power amps are attached to an aluminum heatsink plate which is also connected to the circuit common for these devices The heatsink plate forms an operational module separate from the chassis which allows access to the solder side of the circuit board while power is applied to the circuitry To avoid thermal shutdown of the power amp s they should NOT be operated without their tabs being fastened to the heatsink plate Variations in the frequency response of different production runs of drivers has sometimes required minor adjustments in the equalization crossover components in individual runs of units Some of these components may have values slightly different than those indicated in the schematic
19. high frequency information in stereo and a third amp driver combination and speaker that handles summed Low Frequency LF information below the 500 Hz crossover point The unique audio design ofthese monitors has two important advantages First it provides optimally focused sound in an Ultra Near Field 1 to 3 feet environment This allows higher SPL for the operator while reducing overall ambient sound and adjacent bay crosstalk Second electronic rather than acoustic cancellation of bass frequencies provides positive audible detection of reversed polarity out of phase audio feeds Output limiter circuits are incorporated to protect the speakers and extensive magnetic shielding allows placement immediately adjacent to video monitors with no color impurities 104 dB SPL at two feet e Two analog inputs on balanced XLR connectors e Only two rack spaces high e Stereo analog output of the channels monitored by the left and e Excellent high frequency response for positive detection of right speakers on two balanced XLR connectors background whine and noise e Select AES or analog input source via a front panel toggle switch e Audible and visual indication of phase polarity problems e Select one of two AES input sources via a front panel toggle switch e Thorough magnetic shielding for placement next to video monitors e AES signal status error indication LED e Choice of either VU or PPM high quality mechanical level meters e Headphone output
20. ion in the left and right stereo speaker channels while the third channel reproduces and sums the left and right channel information below the 500 Hz crossover point in the woofer bass speaker s Note that the woofer channel is NOT a dedicated LFE subwoofer or Center channel See page 16 for more information concerning the AMP2 Series audio amplifier speaker configuration Audio Level Meters Mechanical Audio levels for the left and right sources selected for monitoring are respectively displayed in the left and right mechanical level meters The AMP2 DA AVU model uses meters exhibiting VU ballistic characteristics The AMP2 DA APP model uses meters exhibiting PPM ballistic characteristics See page 21 for Threshold Level adjustment and settings for the VU and PPM type of meter 3 Analog Digital Source Select Switch This two position toggle switch allows the operator to choose between two primary input sources ANALOG or DIGITAL e ANALOG Unit will monitor the analog signals as input on the rear panel ANALOG IN XLR connectors Item F page 14 e DIGITAL The unit will monitor the AES signals as input on the selected 1 or 2 rear panel AES EBU IN BNC connector Item C page 12 AES Source Select Switch 1 or 2 This two position toggle switch allows the operator to choose between the two rear panel AES EBU IN digital input connectors 1 or 2 Item C page 12 Note that in order to monitor the selected AES input the Analog Di
21. ld DIP Switch Settings DN aB PPM Dio aB ppm QF 4 dB PPM AU s dB PPM PPM Level Meter Specifications Specify BBC 1 to 7 or EBU type 1 and 2 specified when ordered 6 0 4 or 8 dBv DIP switch selectable internal VU Level Meter Specifications and Level Threshold Adjustment Level Gain Calibration adjustment for the AV VU unit is done by adjusting two trim pots P1 and P2 on the level meter driver PCB 919036V The units top cover must be removed to access this PCB which is mounted in the center of the chassis bottom P1 adjusts the left meter P2 adjusts the right meter Clockwise rotation of either meter will increase the level of the associated meter Adjustment range for each meter is 0 to 8 dBv AVU VU Meter Driver PCB 919036V Turn pots clockwiseto increasethe display level threshold sensitivity in the associated meter OOOOOODOO 02004 Wohler Technologies Inc ALL rights reserved 21 Section 3 Technical Information Y0 21 80 V 19y Webel 19018 JOSUUODI9 U dd W WO ZA NV 8 NAV VG ZdWV paoueleg U MOL 141X l jew 4 Uld YY 1X SIE Uld W H1X isaduepeduy ynduj bojeuy pu 7 10393uu0 ejewsy ONd E peoueleg U 01 4 Y1X pasue equn U S ONE seouepeduy ndu ey1B1q 19481 l AV VOSA ZAMNV l 491 7 A980616 NA x g ul Bojeuy E S I Wwwwasa zawy yooz 188 19
22. of the AES receiver unframer Audio Data Extraction 1C11 Header and ancillary data are removed from the recovered input datastream yielding a datastream having only alternating left right channel audio data which is output on pin 26 of IC11 Digital to Analog Conversion 1C10 The pure audio datastream along with a data clock and a channel ID left right clock are applied to a 20 bit two channel D to A converter IC10 where the datastream is converted into left and right analog outputs Analog buffer 1C4 Output Amplifiers 1C8 1C9 Buffer amps provide balanced left and right channel outputs as well as single ended outputs Gain calibration the analog level which corresponds to a given digital value is settable via a DIP switch The default factory setting is 20 dB below full code digital zero to equal 4 dbu 0 775V The other three settings possible are for 18 dBfs 0 dBu 20 dBfs 0 dBu and 20 dBfs 8 dBu See page 16 for DIP switch location and settings Power Supply The 24V rail internal to the rest of the unit is converted to 5V for digital portions of the 919117 PCB by switching regulator IC12 Error Indication The AES status LED is a bicolor LED Red Green It is green as long as a valid digital data strean is being received The 8412 receiver is capable of indicating two types of error conditions 1 Faulty data data identified by the sending device possibly invalid and 2 Faulty reception errors in r
23. ounding type plug A polarized plug has two blades with one wider than the other A grounding type plug has two blades and a third grounding prong The wide blade or the third prong are provided for your safety If the provided plug does not fit into your outlet consult an electrician for replacement of the obsolete outlet 10 gt Protect the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus 11 Only use attachments accessories specified by the manufacturer 12 gt Use only with the cart stand tripod bracket or table specified by the manufacturer or sold with the apparatus When a cart is used use caution when moving the cart apparatus combination to avoid injury from tip over 13 Unplug this apparatus during lightning storms or when unused for long periods of time 14 gt Refer all servicing to qualified service personnel Servicing is required when the apparatus has been damaged in any way such as when power supply cord or plug is damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rain or moisture does not operate normally or has been dropped 15 Do not expose this apparatus to rain or moisture 16 The apparatus shall be connected to a mains socket outlet with a protective earthing connection CAUTION In products featuring an audio amplifier and speakers the
24. out locating it adjacent to most types of CRT monitors including even high resolution color monitors Heat Dissipation Heat dissipated by the speaker amps is conducted directly to the left side of the chassis no special considerations for cooling are necessary as long as the ambient temperature inside the rack area does not exceed approximately 40 C 104 F Sympathetic Vibration Sympathetic vibration from other equipment cables etc in the rack may be serious enough to interfere with the unit s sound quality out in the listening area The use of thin card stock and or felt or foam weather stripping type materials between adjacent vibrating surfaces or tying up loose cables etc may be required to stop vibrations external to the unit Mechanical Bracing Even though the unit is fairly heavy the chassis is securely attached to the front panel at eight points along its surface not just at the four corners of the chassis ears This feature will reduce or eliminate rear bracing requirements in many mobile portable applications The weight of internal components is distributed fairly evenly around the unit Audio Connections Connection of the audio feeds is straightforward Please refer to the system interconnect block diagram on page 22 for clarification of the general signal paths into and out of the unit AES EBU digital inputs are via female BNC connectors and are configured for 75 2 unbalanced connections Analog inputs are via two
25. surface at the side of the unit where the audio amplifier heat sink is internally attached may get very hot after extended operation When operating the unit excercise caution when touching this surface and ensure that external materials which may be adversely affected by heat are not in contact with it There is a Hot Surface label see diagram attached to the aforementioned surface of the product Introduction Congratulations on your selection of a Wohler Technologies product We are confident it represents the best performance and value available and we guarantee your satisfaction with it If you have questions or comments you may contact us at Wohler Technologies Inc 31055 Huntwood Avenue Hayward CA 94544 Phone 510 870 0810 Fax 510 870 0811 US Toll Free 1 888 596 4537 www wohler com support wohler com 2 2007 Wohler Technologies Inc ALL rights reserved AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Features Specs and Installation Description Features Applications Specifications Installation 2004 Wohler Technologies Inc ALL rights reserved 3 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 1 Features Specs and Installation WWohler AMP2 DA AVU and AMP2 DA APP Powered Audio Monitors O ao n qa AMP2 DA AM DIGITAL AUDIO WOHLER MONITOR PANEL TECHNOLOGIES 7 ANALOG DIGITAL source Source e DIGITAL O O AMP2 DA APP Series FrontPanel The AMP2 D
26. t Right Speaker Speaker Channel EQ Limiter High Pass Amplifier B R AMP2 2U Audio Amplifier and Speaker Block Diagram Balance Control Characteristics The balance control attenuates the signal from the source so that the left and right bass frequencies summed together and reproduced in the woofer channel will also respond to the balance control Example Ifan audio signal of a voice speaking English is fed to the left A input and a voice speaking Spanish is fed to the right B input then the left speaker channel will reproduce the midrange and high range frequencies of the English speaking voice the right speaker channel will reproduce the midrange and high range frequencies of the Spanish speaking voice and the woofer speaker channel will reproduce the summed combined low range frequencies of both voices If the balance control is rotated to the eft English then the Spanish speaking voice in the right speaker channel will diminish in volume and the Spanish speaking voice in the woofer speaker channel will also diminish Note that if the balance control is rotated completely to the left the volume in both the left speaker channel and woofer speaker channel will increase slightly to maintain overall output level See the simplified diagram below for placement of the balance control in the audio amplifier circuit The converse of the above is true if the balance control is rotated to the right 16 2004 Wohler Te
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