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© 2004   Wohler Technologies  Inc.   ALL rights reserved

4

AMP2-DA/AVU

 and 

AMP2-DA/APP

 User Manual  P/N 

 821584 

 Rev-

A

Features

AMP2-DA/AVU

and

AMP2-DA/APP

Powered Audio Monitors

Description

Section 1:

 Features, Specs, and Installation

AMP2-DA/APP Series  Front Panel

• Two analog inputs on balanced XLR connectors

• Stereo analog output of the channels monitored by the left and

right speakers on two balanced XLR connectors

• Select AES or analog input source via a front panel toggle switch

• Select one of two AES input sources via a front panel toggle

switch

• AES signal status/error indication LED

• Headphone output

• Power indication LED

• 104 dB SPL at two feet

• Only two rack spaces high

• Excellent high frequency response for positive detection of
   background whine and noise

• Audible and visual indication of phase/polarity problems

• Thorough magnetic shielding for placement next to video
   monitors

• Choice of either VU or PPM high quality mechanical level meters

• Two selectable AES/EBU inputs on unbalanced BNC connectors

The

AMP2-DA/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 of unbalanced 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 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 of these monitors has two
important advantages.  First, it provides optimally focused sound in an Ultra Near Field 

tm

 (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.

Summary of Contents for AMP2-APP

Page 1: ...r 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 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 Mechanic...

Page 2: ...eing 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 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 ...

Page 3: ...nc ALL rights reserved 3 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Sect 1 General Features and Specifications Features Specs and Installation Description Features Applications Specifications Installation Section 1 ...

Page 4: ... 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 indicati...

Page 5: ...trical Distortion Acoustic Input Overload ConvertedAnalogOutS N ConvertedAnalogOutTHD MagneticShielding PowerConsumption AverageMaximum AC Mains Input AES BNC Analog XLR XLR 70K Ω balanced BNC 75 Ω unbalanced 104 dB SPL 14 W transient 10 W continuous 35 W transient 25 W continuous 80 Hz 16 kHz 5 dB 10 dB 40 Hz 20 kHZ 0 dBv balanced 10 dB unbalanced Better than 68 dB below full output Less than 0 1...

Page 6: ...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 Pleas...

Page 7: ...gies Inc ALL rights reserved 7 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 Section 2 ...

Page 8: ...he 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 Digital Source Select Switch Item 3 m...

Page 9: ... 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 Figure 2a Front Panel Features ...

Page 10: ...or 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 LED indicate...

Page 11: ... 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 Figure 2a Front Panel Features ...

Page 12: ... 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 termina...

Page 13: ... 2004 Wohler Technologies Inc ALL rights reserved 13 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation Figure 2b Rear Panel Features ...

Page 14: ...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 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 Ω connections For XLR connector pin out information see the dia...

Page 15: ... 2004 Wohler Technologies Inc ALL rights reserved 15 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A Section 2 Operation Figure 2b Rear Panel Features ...

Page 16: ...tics 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 If an 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 an...

Page 17: ...ical 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 Section 3 ...

Page 18: ... 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 ...

Page 19: ...a 20 bit two channel D to A converter IC10 where the datastream is converted into left and right analog outputs Analog buffer IC4 Output Amplifiers IC8 IC9 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 ful...

Page 20: ...n Error Jumper Location 919117 Section3 TechnicalInformationMute On Installing a jumper at H12 will mute the audio if errors are detected See page 14 for more information Installing a jumper at H12 will mute the audio if errors are detected See Item 5 page 8 for more information AES to Analog Converter Module PCB 919117 ...

Page 21: ...vel Threshold Settings LevelMeterType LevelMeterScale LevelMeterThreshold LevelMeterDynamics Mechanical StandardVU 0 to 8 dBv factory set to 4 dBv trimpot adjustable internal VU fullANSI LevelMeterType LevelMeterScale LevelMeterThreshold LevelMeterDynamics Mechanical Specify BBC 1 to 7 or EBU type 1 and 2 specified when ordered 6 0 4 or 8 dBv DIP switch selectable internal PPM Level Gain Calibrati...

Page 22: ... 2004 Wohler Technologies Inc ALL rights reserved 22 AMP2 DA AVU and AMP2 DA APP User Manual P N 821584 Rev A AMP2 DA AVU and AMP2 DA APP Interconnect Block Diagram Section3 TechnicalInformation ...

Page 23: ... documentation is available upon request Wohler Technologies Inc 713 Grandview Drive South San Francisco CA 94080 650 589 5676 Fax 650 589 1355 web www wohler com e mail support wohler com 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 ...

Page 24: ...A Wohler Technologies Inc 713 Grandview Drive South San Francisco CA 94080 650 589 5676 Fax 650 589 1355 web www wohler com e mail support wohler com 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 ...

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