Wohler AMP2A-4S, AMP2A-10S User Manual

AMP2A-4S and AMP2A-10S

2U Stereo Audio Speaker Monitors

with Four Selectable (AMP2A-4S) or Ten Selectable

(AMP2A-10S) Analog Stereo Inputs on Phoenix,

Selected Stereo Output on Two XLR, Dual

20-Segment LED Level Meters and Phase Indication

Document P/N 821554 Rev-B

User Manual

CONTENTS

Title and Contents ......................................................

Introduction ......................................................................................

Section 1: General Features and Specs ..................

Description and Features ..................................................................

Applications, Specifications, and Other Options ..............................

Section 2: Operation ..................................................

Installation .......................................................................................

Front Panel Features ........................................................................

Rear Panel Features .........................................................................

Section 3: Technical Information ............................

General Technical Observations ......................................................

Level Meter Settings and Specifications ...........................................

LED Bargraph Driver PCB (919030) Description ...........................

1

2

3

4

5

7

9

10

12

15

16

17

18

Level Meter Bargraph "0" (Zero) Fine Adjustment ..........................

Level Meter Bargraph Peak LED Segment Adjustment ....................

Input Select Analog Switch PCB (919013) Description ...................

AMP2A-4S Interconnect Block Diagram .........................................

AMP2A-10S Interconnect Block Diagram ........................................

19

19

20

21

22

1

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) Do not install near any heat source such as radiators, heat registers, stoves, or other apparatus (including
amplifiers) that produce heat.

9) Do not defeat the safety purpose of the polarized or grounding-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) 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) 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) 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 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: [phone] Fax: [phone]

US Toll-Free: 1-888-596-4537

www.wohler.com [e-mail]

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© 2007 Wohler Technologies, Inc. ALL rights reserved

AMP2A-4S and AMP2A-10S User Manual P/N 821554 Rev-B

Section 1

General Features

and Specifications

Description
Features
Applications

Specifications
Other Options

Sect. 1: General Features and Specifications

© 2003 Wohler Technologies Inc. ALL rights reserved

3

AMP2A-4S and AMP2A-10S User Manual P/N 821554 Rev-B

AMP2A-4S and AMP2A-10S

2U Stereo Audio Speaker Monitors

Section 1: General Features and Specifications

FAST-IN

PHASE

FAST-OUT

AVG

12 34

SOURCE

AMP2A-4S

ANALOG AUDIO

MONITOR PANEL

WOHLER

TECHNOLOGIES

POWER

L

SOURCE

PEAK

10
13
16
19
22
25
28
31
34
37
40

3
2
1
0
1
3
5
7

R

AMP2A-4S Front Panel

FAST-IN

PHASE

FAST-OUT

AVG

4567

3

2

SOURCE

8

9

101

AMP2A-10S

ANALOG AUDIO

MONITOR PANEL

WOHLER

TECHNOLOGIES

POWER

L

SOURCE

PEAK

10
13
16
19
22
25
28
31
34
37
40

3
2
1
0
1
3
5
7

R

AMP2A-10S Front Panel

Description

The AMP2A series units are complete, exceptionally high quality stereo audio monitoring systems in compact, two rackspace
cabinets. These models 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 AMP2A series unique audio design 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. A unique LED display also
visually shows “phase” (polarity) relationships of the signals selected for monitoring.

The AMP2A-4S and AMP2A-10S models are both audio monitors capable of monitoring two analog source channels (one selected
pair) through the stereo speaker system while simultaneously visually monitoring both channels via two 20-segment tri-color LED
bargraph level meters. Both models feature a rotary switch on the front panel to allow selection of one of four (AMP1A-4S) or one
of ten (AMP2A-10S) analog stereo pair input sources for monitoring.

The rear panel for the AMP2A-4S model features four selectable stereo pairs of analog inputs on balanced Phoenix connectors. The
rear panel for the AMP2A-10S model features ten selectable stereo pairs of analog inputs on balanced Phoenix connectors. Both
models offer an analog output of the selected stereo source on two XLR connectors on the rear panel.

Features

• AMP2A-4S model features four selectable stereo pairs of

analog inputs on balanced Phoenix connectors

• AMP2A-10S model features ten selectable stereo pairs of

analog inputs on balanced Phoenix connectors

• Both models offer front panel selection of the stereo pair input
source to be monitored

• Two 20-segment LED bargraph display level meters

• Volume and balance controls

• Stereo phase indication LEDs

• Headphone output

• Power indication LED

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© 2003 Wohler Technologies Inc. ALL rights reserved

• 98 dB SPL at two feet

• Only two rack spaces high

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

• Audible indication of phase/polarity problems

• Thorough magnetic shielding for placement next to video
monitors

• Numerous alternate control and input options

• Quick and easy installation: simply slide in the rack and
connect audio and AC power

AMP2A-4S and AMP2A-10S User Manual P/N 821554 Rev-B Section 1: General Features and Specifications

Applications

The AMP2A-4S and AMP2A-10S 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

Analog Input Connectors:

Analog Input Impedance:

Peak Acoustic Out (@ 2 ft.):

Power Output,

ΩΩ

Ω):

ΩΩ

ΩΩ

Ω):

ΩΩ

RMS Each Side (4
RMS Bass (4

Frequency Response,
Sixth Octave:

Input Level for Maximum
Output (Volume Full On):

Hum and Noise (analog):

Distortion, Electrical:

Distortion, Acoustic:

Input Overload:

Analog Out S/N:

Analog Out THD:

Magnetic Shielding:

Power Consumption
(Average Maximum):

AC Mains Input:

Phoenix Terminal Block (3-pin, male)

40K Ω, balanced

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 0.15% at any level below
input threshold

6% or less at worst case frequencies
above 120 Hz, including cabinet
resonance; typically less than 1.5%

+26 dBv balanced

>90 dB

<0.008%

<0.8 Gauss any adjacent surface

45 W

100-240VAC, 50-60 Hz Universal

Level Meter Specifications

Level Meter Type:

Meter Dynamics:

Level Gain:

Dynamic Range:

Midscale Resolution:

Segment Colors:

Scale:

Note: See page 17 for additional bargraph information..

20-Segment LED bargraph

VU or PPM, selectable

-6, 0, +4,+8 dBu, selectable

44 dB

1 dB

Tricolor (green, amber, red)

+4 (peak) to -40 dB

Physical Specifications

Weight:

Dimensions (HxWxD):

18 lbs. (8.2 kg)

3.5 x 19 x 12 inches
(89 x 483 x 305 mm)

Audio Response Curve

+10

0

d

-10

B

-20

-30

5k

Hz

Typical 1/6 Octave Audio Response Curve

2k1k50020010050 20k20

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.

10k

Other Options

Wohler Technologies offers by far the broadest range of standard production audio monitor units. Custom combinations of
connectors, controls and level meters are available by special order. Standard-production models or special order custom features
for the AMP2A series (2U) units include the following functions (and combinations thereof):

• Transformer coupled analog inputs

• Separate channel volume controls

• Mono, mute, and mode switches

• Alternate level meter scales and color maps

Other custom options are possible. Call your dealer or Wohler Technologies to discuss your specific needs.

© 2003 Wohler Technologies Inc. ALL rights reserved

• FULL output power DC operation

• External speaker capability

• Multiple input and output connector type choices

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AMP2A-4S and AMP2A-10S User Manual P/N 821554 Rev-B

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© 2003 Wohler Technologies Inc. ALL rights reserved

AMP2A-4S and AMP2A-10S User Manual P/N 821554 Rev-B

Section 2

Operation

Installation

Front Panel Features

Rear Panel Features

© 2003 Wohler Technologies Inc. ALL rights reserved

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AMP2A-4S and AMP2A-10S User Manual P/N 821554 Rev-B Section 2: Operation

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© 2003 Wohler Technologies Inc. ALL rights reserved