Wohler AMP2A-VTR User manual

AMP2A-VTR and AMP2A-VTR2
2U Stereo Audio Speaker Monitors
with Four Inputs (AMP2A-VTR) or Two Banks
of Four Inputs (AMP2A-VTR2) on Phoenix,
Summable Independant Left/Right Speaker Channel
Assignment, Selected Stereo Output on Two XLR, Four
53-Segment LED Level Meters, and Phase Indication
Document P/N 821580 REV-B
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Title and Contents ..............................................................
Important Safety Instructions and 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 ......................................
Section 3: Technical Information ................................
General Technical Observations .......................................................
Level Meter Rear Panel 6-Position DIP Switch Settings ....................
Level Meter Internal 10-Position DIP Switch Settings .......................
Level Meter DIP Switch Locations ..................................................
Level Meter Alternative Scales ........................................................
Level Meter Phase Correlation Feature ............................................
AMP2-VTR Interconnect Block Diagram .........................................
AMP2-VTR2 Interconnect Block Diagram .......................................
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CONTENTS
User Manual
© 2004 Wohler Technologies Inc. ALL rights reserved

2© 2007 Wohler Technologies, Inc. ALL rights reserved
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]
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.
Important Safety Instructions
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.

© 2004 Wohler Technologies Inc. ALL rights reserved 3
AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B
Sect. 1: General Features and Specifications
General Features
and Specifications
Description
Features
Applications
Specifications
Installation
Section 1

© 2004 Wohler Technologies Inc. ALL rights reserved
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AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B
Features
AMP2A-VTR and AMP2A-VTR2
Description
Section 1: General Features and Specifications
AMP2A-VTR2 Front Panel
2U Stereo Audio Speaker Monitors
AMP2A-VTR Front Panel
The AMP2A-VTR and AMP2A-VTR2 are audio monitors capable of audibly monitoring up to four Analog source channels
through an internal stereo speaker system while simultaneously visually monitoring all four channels of the selected source via four
high-resolution 53-segment LED bargraph level meters. Two banks of four buttons on the front panel are used to independently
assign from one to four (summed) channels to each of the two (left and right) speaker channels. Features for these two models
include a ganged stereo volume control and balance pot, power indication LED, headphone output, and a stereo analog output on
two balanced XLR connectors of the channels assigned to the left and right speaker channels. Output limiter circuits are
incorporated to protect the speakers, and extensive magnetic shielding allows placement immediately adjacent to video monitors
with no color impurities. Wohler Technologies proprietary three-LED stereo phase indication feature allows monitoring of phase
relationships of the selected channels assigned to the left and right speaker channels. The four 53-segment LED bargraph level
meters offer selectable Input Reference Level, Display Mode, Peak Hold, Ballistics, Phase Correlation, and alternate scales.
The AMP2A-VTR rear panel features Analog inputs on four balanced Phoenix connectors. The AMP2A-VTR2 rear panel features
two banks of four Analog inputs (eight total) on balanced Phoenix connectors and a front panel toggle switch for choosing between
the two banks of four inputs.
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 AMP2 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.
• Two banks of four push buttons for assigning single or
summed channels to the left and right speakers
• Digital/analog source selection via front panel toggle switch
• Headphone output
• Power indication LED
• AMP2A-VTR: Analog audio inputs on four balanced
Phoenix connectors
• AMP2A-VTR2: Analog audio inputs on two banks of four
balanced Phoenix connectors with front panel toggle switch
• Analog outputs of source selected for speaker monitoring
on two balanced XLR connectors
• Numerous control and input options
• Quick and easy installation: simply slide in the rack and
connect audio and AC power
• 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
• Four 53-segment high-resolution tri-color bargraph level meters:
-Selectable Input Referrence Level (0, +4, +6, or +8 dBu)
-Selectable Display Mode (VU Only, VU/PPM, or PPM Only)
-Selectable Peak Hold (Manual, 3-Second, 10-Second, or Off)
-Selectable Ballistics (Type I, Type II, DIN 45406, or SSRT)
-Selectable alternate Bargraph Scales (AES, Extended VU,
Alternative AES, VU, BBC, NORDIC, and DIN)
-Selectable Phase Correlation feature

© 2004 Wohler Technologies Inc. ALL rights reserved 5
AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B Section 1: General Features and Specifications
Applications
The AMP2A-VTR and AMP2A-VTR2 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.
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.
General Specifications
Analog Input Connectors:
Analog Input Impedance:
Peak Acoustic Out (@ 2 ft.):
Power Output,
RMS Each Side (4ΩΩ
ΩΩ
Ω):
RMS Bass (4ΩΩ
ΩΩ
Ω):
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)
90KΩ, 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
Physical Specifications
18 lbs. (8.2 kg)
3.5 x 19 x 12 inches
(89 x 483 x 305 mm)
Weight:
Dimensions (HxWxD):
Many custom options are possible. Call your dealer or
Wohler Technologies to discuss your specific needs.
Level Meter Specifications
Level Meter Type:
Display Modes (select):
Peak Hold (select):
PPM Ballistics (select):
Reference Levels:
Phase Correlation:
Bargraph Scales:
Dynamic Range:
Midscale Resolution:
Segment Colors:
Scale:
Segment Size:
53-Segment tri-color (R,A,G) LED
VU, PPM, or VU/PPM
Manual, 3-sec, 10-sec, or OFF
Type 1, Type 2, DIN 45406, or SSRT
0, +4, +6, +8 dBu (DIP selectable)
ON or OFF
VU, Ext. VU, BBC, NORDIC, or DIN
65 dB
1 dB
Tricolor (green, amber, red)
+15 to -50 dB
.158" x .04" (4.0132 x 1.016 mm)
Audio Response Curve
Typical 1/6 Octave Audio Response Curve
B
d
0
+10
-20
-30
-10
Hz
10k
5k
2k1k50020010050 20k20