Wohler AMP1A-VTR2 User manual

World Leader of In-Rack, Audio, Video, Data Monitoring, and Closed Captioning Solutions
CONFIDENCE IS EVERYTHING.™
AMP V Series
• AMP1A-VTR2 • AMP2-VSDA
•AMP1-V2DA
Digital/Analog Audio Speaker Monitors
User Guide
Part Number 821021, Revision A

© 2010 Wohler Technologies, Inc. All rights reserved.
ii
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Last Update
January 12, 2010

© 2010 Wohler Technologies, Inc. All rights reserved. 1
AMP V Series User Guide
Introduction
Overview
The AMP V Series monitors 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 LED bar
graph level meters.
Topics
Topics Page
Introduction 1
Safety Instructions 2
Installation Recommendations 3
Description 4
Features 5
Specifications 6
Audio Amplifier and Speaker Configuration 7
Front Panel Controls 8
Rear Panel Connectors 13
Line Level Calibration Instructions 17
Internal Switch Settings 20
Technical Functional Overview 24

© 2010 Wohler Technologies, Inc. All rights reserved.
2
AMP V Series User Guide
Safety Instructions
Safety Instructions
1. Read, keep, and follow all of these instructions; heed all warnings.
2. Do not use this equipment near water.
3. Use only a dry cloth to clean the equipment.
4. Do not block any ventilation openings. Install only in accordance
with the instructions in the section entitled, “Installation
Recommendations” on page 3.
5. Do not install near any heat source such as a radiator, heat register,
amplifier, or stove.
6. Do not expose the equipment to rain or moisture.
7. Do not attempt to plug the unit into a two-blade outlet (with only
two prongs of equal width).
8. Protect the power cord from being walked on or pinched,
particularly at plug’s source on the equipment and at the socket.
9. Use only the attachments/accessories specified by the
manufacturer.
10. Unplug the equipment during lightning storms or when unused
for long periods of time.
11. Refer all servicing to qualified service personnel. Servicing will be
required under all of the following conditions:
•The equipment has been damaged in any way, such as when
the power-supply cord or plug is damaged.
•Liquid had been spilled or objects have fallen onto the
equipment.
•The equipment has been exposed to rain or moisture.
•The equipment does not operate normally.
•The equipment has been dropped.
IMPORTANT: By design, these monitors will only plug into a three-prong outlet for
your safety. If the plug does not fit into your outlet, contact an
electrician to replace the obsolete outlet.

© 2010 Wohler Technologies, Inc. All rights reserved. 3
AMP V Series User Guide
Installation Recommendations
Installation Recommendations
Unpacking
Unpack the AMP V Series monitor from the shipping container and
inspect all components for shipping damage. If you find any damage,
notify the shipping carrier for claims adjustments.
Compare the shipping box contents to the packing slip. Contact
Wohler’s customer support personnel about any discrepancies.
(Wohler’s contact information in on the copyright page ii, of this
manual).
Heat Dissipation
The ambient temperature inside the mounting enclosure should not
exceed 40°Celsius (104°Fahrenheit). Adjacent devices can be rack
mounted (or stacked) in proximity to the unit if the above temperature
is not exceeded. Allow a 1RU (1.75”/44.45mm) space above and below
the unit for air circulation.
Rack Mounting
You should install the monitor into a standard 19" rack and requires a
maximum of 3RU of rack space (the 2RU unit, plus 1RU above and
below). Also, install it as close to the operator’s direct viewing angle as
possible as LCD screens can appear to display anomalies outside this
viewing angle.
Cable Connections
Wohler recommends Beldon 8281 or Belden 1694A cables for analog
video signals and Beldon 9451 cables for analog audio signals.
Important: The heat generated by the power amplifiers, power supplies, and other
components is vented by slots in the side of the unit. Therefore, as a
safety precaution, we advise you to be sure to allow proper ventilation
on both sides of the unit.

© 2010 Wohler Technologies, Inc. All rights reserved.
4
AMP V Series User Guide
Description
Power
Each unit comes with a standard 24VDC/3.0A internal power supply
and connects an A/C mains power source (65W, 100 to 240 VAC, 50/
60Hz) to the IEC connector provided on the rear panel of the unit.
Electrostatic Discharge (ESD)
As with most electronic equipment, static discharges can damage
components within the unit. Take precautions to ensure your
installation environment is not subject to ESD.
Description
In addition to the four high-resolution LED bar graph level meters, the
AMP V Series monitors also provide two banks of four buttons on the
front panel which 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 stereo volume control and
balance control, 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 LED bar graph level meters offer selectable
Input Reference Level, Display Mode, Peak Hold, Ballistics. Phase
Correlation and alternate scales are available as options.

© 2010 Wohler Technologies, Inc. All rights reserved. 5
AMP V Series User Guide
Features
Features
•98 dB SPL at two feet
•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 high-resolution tri-color bargraph level meters:
•Selectable input reference 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 bar graph scales (Extended VU is
standard) Alternative AES, VU, BBC, NORDIC, and DIN
scale labels are available as an option.
•Selectable phase correlation (labels available as option F).
•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

© 2010 Wohler Technologies, Inc. All rights reserved.
6
AMP V Series User Guide
Specifications
Specifications
Table 1–1 lists the specifications for the AMP V Series monitors.
Table 1–1 AMP V Series Monitors Specifications
Specifications AMP1-V2DA AMP1-VTR2 AMP2-VSDA
Level Meter Type 26-Segment 53-Segment
Tri-Color (red, amber, green) LED Bar Graph
Segment Size .158” x .04” (4.0132 mm x 1.016 mm)
Peak Hold (selectable) Manual, 3 sec, 10 sec, or off
Dynamic Range 62 dB 65 dB
Scale +12 to -50 db + 16 to -50 dB
Bar Graph Scales VU, Ext, VU, BBC, Nordic, or Din
Midscale Resolution 1 dB
Input Connectors 4 Analog (Phoenix)
2 AES (BNC) 8 Analog (Phoenix)
4 Analog (XLR)
2 AES (XLR/BNC)
1 SDI (BNC)
Analog Input Impedance Phoenix: 200k balanced Phoenix: 90k balanced XLR: 70k balanced
Digital Input Impedance BNC: 75 unbalanced — BNC: 75 unbalanced
XLR: 110 balanced
Input Level for Maximum
Output (Volume Full On) 0 dBv balanced; -10 dB unbalanced
Peak Acoustic Ouptut
(@ 2 ft.) 98 dB SPL 104 dB SPL
Frequency Response, Sixth
Octave
80 Hz to 16 kHz ± 7 dB
(-10 dB @ 50 Hz, 22kHz)
80 Hz to 16 kHz ± 5 dB
(-10 dB @ 40 Hz, 20kHz)
Power Output
RMS Each Side (4)
RMS Bass (4)
10 W transient/5 W continuous
20 W transient/10 W continuous
14 W transient/
10 W continuous
35 W transient/
25 W continuous
Distortion, Electrical < 0.15% at any level below input threshold
Distortion, Acoustic 8% or less at worst case frequencies aove 180 Hz
including cabinet resonance; typically less than 2%
6% or less at worst case
frequencies aove 180 Hz
including cabinet
resonance; typically less
than 1.5%
Hum and Noise Better than -68 dB below full output
Magnetic Shielding < 1 Gauss any adjacent surface < 0.8 Guass any adjacent
surface
Power Consumption 35W 45 W
AC Mains Input 100 to 240 V AC, 50 to 60 Hz Universal
Weight 10 lbs. (4.53 kg) 18 lbs. (8.2 kg)
Dimenstions (H x W x D) 1.7” Hx 19” W x 12” D (43 mm x 483 mm x 305 mm) 3.5” H x 19” W x 12” D
(89mm x 483mm x 305mm)

© 2010 Wohler Technologies, Inc. All rights reserved. 7
AMP V Series User Guide
Audio Amplifier and Speaker Configuration
Audio Amplifier and Speaker
Configuration
Audio Amplifiers
All AMP V Series models contain high performance 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 below the 500 Hz crossover point in the
woofer (bass) speaker(s). Note that the woofer channel is not a
dedicated LFE or center channel.
Speaker Configuration
The 1U rack size AMP1 Series products are configured with two
speakers (left and right) to reproduce mid- and high-range audio
frequencies (in stereo), but feature two woofer speakers to reproduce
the summed (combined) low-range audio frequencies from the left and
right speaker input channels. It should be noted that both woofer
speakers, which are wired in series, are driven from one woofer
speaker channel, and are not stereo. See the simplified diagram below
for a block diagram of the AMP1 Series audio amplifier/speaker
configuration. The 2RU AMP2 is similar, except the side speakers are
larger and has only one woofer.
Figure 1–1 Audio Amplifier and Speaker
Configuration

© 2010 Wohler Technologies, Inc. All rights reserved.
8
AMP V Series User Guide
Front Panel Controls
Front Panel Controls
Common Controls
•Speakers: The AMP1 V Series monitors feature two mid-range
speakers (left and right) and two woofer speakers (one woofer in the
AMP2 models). Combinations handle midrange and high frequency
information 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. Note that the woofer channel is not a dedicated LFE
(subwoofer) or center channel.
•Headphones: This jack accepts a standard 1/4” phone type stereo
plug. When you plug in headphones, the internal or external
speakers will mute.
•Source or Left Speaker/Right Speaker (Assign): Use the left bank
of four buttons to assign one to four of the four available channels
for monitoring from the left speaker channel. Use the right bank of
four buttons to assign one to four of the four available channels for
monitoring from the right speaker channel. Channel buttons toggle
on/off and will light up blue to indicate they are selected. Operation
for each bank of four buttons is as follows:
•Single Channel Select: Press and release a single channel
button to select that channel (and deselect any previous
selection). Pressing and releasing the selected channel button
again will deselect it.
•Multi-Channel Select (Summing): Press and hold down a
desired channel button, then press other channel buttons to
add (sum) additional channels (or press any again to
deselect). Release all buttons to accept the selection set. When
multiple channels are selected, pressing and holding an
already selected channel button will allow further
modification to the selection set. Releasing all buttons accepts
the new selection set. Pressing and immediately releasing an
already selected channel button will select only it and deselect
all other channel selections.
If the user presses a previously selected (lighted) channel button,
but then decides not to make any changes to the selection set, the
user should keep the button depressed for at least 1.5 seconds

© 2010 Wohler Technologies, Inc. All rights reserved. 9
AMP V Series User Guide
Front Panel Controls
before releasing it. This will preserve the current selection set as
though the button was never pushed.
•Level Meters: Audio levels for the four selected source channels
are displayed via these four tri-color LED bargraph meters. The four
bar graph meters display levels for the digital or analog sources as
selected by the Analog/Digital source select switch. All bar graph
LED segments are of the tri-color type (green, amber, red) and are
user adjustable for reference level, display mode, peak hold, PPM
ballistics, alternate bar graphscales, and phase correlation via DIP
switches on the rear panel and inside the unit.
•Volume (Rotary Knob): 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 in the speakers or headphones.
•Power (LED): This LED glows green to indicate the unit is
connected to mains power and an operation voltage is present.
•Phase (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 show instantaneous (fast)
phase relationships in the signal. The larger LED labeled AVG will
indicate the average phase condition.
•+: The green fast LED glows (or blinks) for in-phase signals.
•-: The amber fast LED glows (or blinks) 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 LED indicates
an out-of-phase alarm condition.
•Brightness (Potentiometer): This control is recessed into the front
panel and can be accessed using a small screwdriver. Turning it
clockwise will increase the relative brightness of all bar graph
display LED segments.

© 2010 Wohler Technologies, Inc. All rights reserved.
10
AMP V Series User Guide
Front Panel Controls
•Balance (Rotary Knob): This adjusts the volume balance between
the left and right speakers or headphones with the left and right
bass frequencies (summed together and reproduced in the woofer
channel) also responding to the balanced control.
AMP1A-VTR2-Specific Controls
Figure 1–2
Group Select (Toggle Switch): On the AMP1A-VTR2 model, this
switch selects between the two groups (Group 1 or Group 2) of four
channels as input on the rear panel. It is from the selected group of four
channels that the Source Speaker Assign channel buttons are used
to independently assign channels to the right and left speakers.
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 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-ranged of both voices.
Speakers
Headphones
Speaker Assign
Group
Level Meters
Balance
Phase Brightness
Volume
Power

© 2010 Wohler Technologies, Inc. All rights reserved. 11
AMP V Series User Guide
Front Panel Controls
AMP1-V2DA-Specific Controls
Figure 1–3 AMP1-V2DA Front Panel
•Analog/Digital Select (Toggle Switch): This two position switch
selects between two primary input sources, analog or digital. When
this toggle switch is set to analog, the unit will monitor the signals
as input on the rear panel Analog In phoenix connectors. When
this toggle switch is set to digital, the unit will monitor the AES
digital source as input on the rear panel AES In BNC connectors.
•AES 1 & 2 (LEDs): These two bi-color (green/red) LEDs indicate
the input presence and status of the two AES input signals. These
LEDs function whether or not the AES digital signals are selected
for monitoring through the unit. Either LED glows green as long as
a valid AES digital datastream for the associated input channel is
being received. Either LED glows red to indicate errors in reception
or data errors (if the data has been tagged as inappropriate for
conversion to analog by having the validity bit set).
Speakers
Power
Volume
Speaker Assign
Headphones Phase
Level Meters
Analog/Digital
Brightness Balance
AES 1 & 2

© 2010 Wohler Technologies, Inc. All rights reserved.
12
AMP V Series User Guide
Front Panel Controls
AMP2-VSDA-Specific Controls
Figure 1–4 AMP2-VSDA Front Panel
•Analog/Digital Select (Toggle Switch): This two position switch
selects between two primary input sources, analog or digital. When
this toggle switch is set to analog, the unit will monitor the signals
as input on the rear panel Analog In phoenix connectors. When
this toggle switch is set to digital, the unit will monitor whichever
source is selected by the AES/SDI switch.
•AES/SDI (Toggle Switch): This two position toggle switch allows
the operator to choose between the two digital input sources; SDI or
AES. When this toggle switch is set to AES, the unit will monitor the
AES signals as input on the AES In BNC or XLR connectors (In 1
and In 2) on the rear panel. When this toggle switch is set to SDI,
the unit will de-embed and monitor the SDI signals as input on the
SDI In BNC connector on the rear panel.
•AES (1 & 2, LEDs): These two bi-color green/red LEDs (AES1 and
AES2) indicate the input presence and status of the two AES input
signals. Each LED glows green as long as a valid AES/EBU digital
datastream for the associated input channel is being received. Each
LED glows red to indicate errors in signal reception or data errors (if
the data has been tagged as inappropriate for conversion to analog
by having the validity bit set). These LEDs function whether or not
the AES digital signals are selected for monitoring through the unit.
•SDI (LED): This bi-color (green/red) LED, labeled SDI, glows
green as long as a valid SDI digital datastream is being received. It
glows red if TSR errors are present in the signal. If there is no SDI
Speakers
Power
Speaker Assign
Headphones
Phase
Analog/Digital
AES/SDI
Balance
AES 1 & 2
Volume
Brightness SDI
Level Meters

© 2010 Wohler Technologies, Inc. All rights reserved. 13
AMP V Series User Guide
Rear Panel Connectors
signal present the LED will be unlit. This LED functions whether or
not the SDI digital signal is selected for monitoring through the unit.
Rear Panel Connectors
Common Connectors Descriptions
•Power: Attach a standard IEC-320 power cord between this
connector and mains power (100 - 250VAC, 50/60 Hz). The front
panel Power LED will glow green to indicate operating voltages are
present.
•Selected Output (Two, 3-Pin XLR Male): These connectors are
analog outputs of the monitor mix as selected by the left and right
Speaker Assign channel buttons and source switches on the front
panel. The left connector outputs the left channel (Chan. A (L)) and
the right connector outputs the right channel (Chan. A (L)). 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 connector pin-out information in Figure
1–5 below.
Figure 1–5 Selected Output 3-Pin Male XLRs
Line Level Calibration (Six-Position DIP Switch): This DIP switch sets
the line level calibration, reference level, and PPM/VU display mode
for the level meter LED bar graph displays on the front panel. The pin-
out is silk-screened onto the the rear panel.

© 2010 Wohler Technologies, Inc. All rights reserved.
14
AMP V Series User Guide
Rear Panel Connectors
AMP1-VTR2-Specific Connectors
Figure 1–6 AMP1-VTR2 Rear Panel
•Analog Input (3-Pin Phoenix Male, Channels 1 through 4, Group 1
or 2): These connectors accept standard analog audio signals and
are configured for balanced 90K Ωconnections. The banks (groups)
of input connectors are interleaved and either group of four inputs
(Group 1 or Group 2) may be selected for monitoring using the two-
position Group select switch on the front panel. Channel input
numbers are silk-screened above the connectors (Channel 1, 2, 3, 4)
and correspond to the numbers available for selection by the left
and right Speaker Assign channel buttons on the front panel.
Connector pinout information is silk-screened just above each
connector.
AMP1-V2DA-Specific Connectors
Figure 1–7 AMP1-V2DA Rear Panel
•AES In (1 & 2, on BNC): These input connectors receive industry
standard, unbalanced (75) AES signals. Note that the unit will
monitor the AES inputs only when the Analog/Digital source
select switch is set to Digital.
•AES Out (1 and 2, on BNC): These two unbalanced (75 ) loop-
through connectors each output a copy of the signal entering the
corresponding AES input connector.
33
1 2 1 2
Technologies
Wohler
www.Wohler.com
[phone]
[phone]
Fax
Tel
AMP1A-VTR2
253836 123456
GROUP 1
+
INPUTS
GROUP 1
CHANNEL 1
-
+
CHANNEL 2
GROUP 2
-
GROUP 1
++
-
GROUP 2
+
-
CHANNEL 3
GROUP 1
-
++
-
GROUP 2
CHANNEL 4
GROUP 2
-
+
-
SEL. OUT CH A(L)
SEL. OUT CH B(R)
CALIBRATE
OPERATE
SERIAL NO. MONTH
YEAR
50/60 Hz 1.0 A
100-240 VAC
23
PPM/PPM
4 5
0
CALIB
METER
+8
+4
+6 VU/PPM
PPM
VU/VU
MODE
DISPLAY
MADE IN U.S.A.
Power Line Level Calibration
Selected Analog Out L&R
Analog Inputs (2 Banks 4)
33
1 2 1 2
Technologies
Wohler
[phone]
[phone]
www.Wohler.com
Fax
Tel
123456
CONVERTED ANALOG OUT
Term. 1
AES/EBU PORTS
IN 1 OUT 1 OUT 2
Term. 2
IN 2
GAIN
1324
ANALOG IN
SEL. OUT CH A(L)
SEL. OUT CH B(R)
CALIBRATE
OPERATE
LO
HI
0 -18
-20
-9
+4
+6
GAIN CALIB
DIGITAL
-20
dBFS
+8
dB
AMP1-V2DA
253832
50/60 Hz 1.0 A
100-240 VAC
SERIAL NO. MONTH
YEAR
23
PPM/PPM
4 5
0
CALIB
METER
+8
+4
+6 VU/PPM
PPM
VU/VU
MODE
DISPLAY
Power AES Termimation
AES/EBU I/O, 1 & 2
AES Gain Calibration
Analog I/O
Line Level Calibration
Selected Audio Out L&R

© 2010 Wohler Technologies, Inc. All rights reserved. 15
AMP V Series User Guide
Rear Panel Connectors
•AES Termination (Four-Position DIP Switch): This DIP switch sets
the termination for the AES inputs. If an AES input channel is fed to
downstream equipment, the associated DIP switch must be in the
up position (unterminated). If no downstream equipment is
connected, the switch must be in the down position (terminated).
See Figure 1–8 for details.
Figure 1–8 AES Termination DIP Switch Settings
•Analog Input (3-Pin Phoenix Male, Channels 1 through 4): These
connectors accept standard analog audio signals and are configured
for balanced 90K Ωconnections. The banks (groups) of input
connectors are interleaved and either group of four inputs (Group 1
or Group 2) may be selected for monitoring using the two-position
Group select switch on the front panel. Channel input numbers are
silk-screened above the connectors (Channel 1, 2, 3, 4) and
correspond to the numbers available for selection by the left and
right Speaker Assign channel buttons on the front panel.
Connector pinout information is silk-screened just above each
connector.
•AES Gain Calibration (Two-Position DIP Switch): This DIP switch
calibrates the AES analog level that corresponds to a given digital
input value. The factory setting is +4 dB (analog) = -20 dBFS
(digital).
Figure 1–9 AES Gain Calibration DIP Switch
Settings

© 2010 Wohler Technologies, Inc. All rights reserved.
16
AMP V Series User Guide
Rear Panel Connectors
•Converted Analog Out (Converted from AES Inputs) (Phoenix, 3-
Pin Male, Outputs 1 through 4): These connectors output standard,
balanced analog signals converted from the AES digital inputs (but
not the analog inputs) and are not affected by the position of the
Analog/Digital source select swich.
AMP2-VSDA-Specific Connectors
Figure 1–10 AMP2-VSDA Rear Panel
•AES In (1 & 2, on XLR-F): These input connectors receive industry
standard, balanced (110 ) AES signals. Note that the unit will
monitor the AES inputs only when the Analog/Digital source
select switch is set to Digital and the AES/SDI source select switch
is set to AES.
•AES In (1 & 2, on BNC): These input connectors receive industry
standard, unbalanced (75) AES signals. Note that the unit will
monitor the AES inputs only when the Analog/Digital source
select switch is set to Digital.
S
DIGITAL SOURCE
SELECTED
ANALOG OUT FROM
12
3
www.Wohler.com
Fax
Tel
Technologies
Wohler
[phone]
[phone]
253358
AMP2-VSDA
CALIB.
GAIN
TERM 1
2
CH 1 CH 2
ANALOG IN
CH 3 CH 4
AES/EBU PORTS
SDI
OUT-FROM
AES
AES
IN 1
AES
IN 2 OUT-FROM
AES
SDI OUT
SDI
IN
AES IN 1 AES IN 2
0 -18
-20
-9
+4
+6
GAIN CALIB
DIGITAL
-20
dBFS
+8
dB
HI
LO
HI
LO LO
HI HI
LO
123 4
CALIBRATE
13 25
4
OPERATE
6
SEL. ANALOG OUT
CH A (L) CH B (R)
100-240 VAC
50/60 Hz 1.0 A
YEAR
MONTH
SERIAL NO.
3
21
3
21 2
3
1
3
21
3
21
3
21
1 2
3
MADE IN U.S.A.
Power
AES In 1 & 2
Gain Calibration Analog Out from
Selected Digital Source Analog Audio In (1 thru 4)
AES/EBU In 1 & 2 and
AES Out from SDI 1 & 2
AES
Term SDI I/O Line Level Calibration
Selected Analog Audio Out L & R
Important: Do not input signals simultaneously to the AES BNC connectors and
the AES XLR connectors of the same channel (i.e., BNC AES In 1 and
XLR AES In 1.
Important: Do not input signals simultaneously to the AES BNC connectors and
the AES XLR connectors of the same channel (i.e., BNC AES In 1 and
XLR AES In 1.

© 2010 Wohler Technologies, Inc. All rights reserved. 17
AMP V Series User Guide
Line Level Calibration Instructions
•AES Out from SDI (1 and 2, on BNC): These two unbalanced (75
) loop-through connectors each output a copy of the de-embedded
audio from the SDI input.
•AES Termination (Four-Position DIP Switch): This DIP switch sets
the termination for the AES inputs. If an AES input channel is fed to
downstream equipment, the associated DIP switch must be in the
up position (unterminated). If no downstream equipment is
connected, the switch must be in the down position (terminated).
See Figure 1–8 for details.
•SDI In and Out (BNC-F): This unbalanced (75 ) input connector
receives standard SD-SDI signals. The unit monitors Subgroup 1
(Channels 1 and 2) and Subgroup 2 (Channels 3 and 4) of SDI
Group 1. Note that the unit will monitor the SDI input only when
the Analog/Digital source select switch is set to Digital, and the
AES/SDI digitial source select switch is set to SDI.
The unbalanced (75 ) SDI Out loop-through connector outputs a
reclocked copy of the signal entering the SDI In connector.
•Analog Out from Selected Digital Source (3-Pin Phoenix Male,
Outputs 1 through 4): The balanced (75 ) connectors ouput analog
signals converted from the selected digital inputs (but not the
analog inputs). These outputs are not affected by the position of the
Analog/Digital souce select switch. The pin-out is silk-screened
onto the the rear panel.
Line Level Calibration Instructions
Figure 1–11 Calibration Settings

© 2010 Wohler Technologies, Inc. All rights reserved.
18
AMP V Series User Guide
Line Level Calibration Instructions
Line Level (Auto) Meter Calibration
The unit is calibrated at the factory prior to shipping for +4 dBU = -20
dBFS = 0dB on the meter. To recalibrate:
1. Turn on the power.
2. Apply the desired reference level (nominal 0) signal to all
channels.
3. Make sure the Reference Level DIP sections (2 and 3) are set to the
nearest level of the input signal being applied for calibration (i.e.,
0, +4, +6 or +8). The user should make sure that the signal applied
to all four channels is within +/- 4 dB of the reference level
selected by DIP switch sections 2 and 3.
4. Place DIP section 1 in the down position.
5. Wait 10 seconds. The unit will remove the previous calibration and
the new calibration will be applied.
Note: Position 6 of the DIP Switch is not used.
Note: For more accurate indication of signal levels, meters are
tuned to effect a “rounding” function, which occurs between
the thresholds of any two bar graph segments. This means
the level meter zero (0) LED sigment will turn on at one-half
the smallest spacing between LED segments (mid-scale
resolution) before that segment’s scale indication.
Table 1–2 Meter Segment Rounding Offsets
Scale 26-Segment Bar
Graphs 53-Segment Bar Graphs
Analog, Extended VU
.5 dB .5 dB
Digital
Nordic
DIN
BBC .125 dB
VU .25 dB
Example: Using the Extended VU scale, a meter calibrated for a +4 dBu nominal
level will actually turn the zero LED segment of the level meter on at
+3.5 dBu (and so all segments will turn on at 0.5 dBu before that
segment’s scale indication.