Wohler AMP2A-VTR, AMP2A-VTR2 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

User Manual

CONTENTS

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 .......................................

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:

Phone: (510) 870-0810 Fax: (510) 870-0811

www.wohler.com support@wohler.com

Wohler Technologies, Inc.

31055 Huntwood Avenue

Hayward, CA 94544

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

AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B

Section 1

General Features

and Specifications

Description

Features

Applications

Specifications

Installation

Sect. 1: General Features and Specifications

AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B

AMP2A-VTR and AMP2A-VTR2

2U Stereo Audio Speaker Monitors

AMP2A-VTR Front Panel

AMP2A-VTR2 Front Panel

Description

Section 1: General Features and Specifications

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.

Features

• 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

• 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

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.

General Specifications

Analog Input Connectors:

Analog Input Impedance:

Peak Acoustic Out (@ 2 ft.):

Power Output,

ΩΩ

Ω):

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:

Phoenix Terminal Block (3-pin, male)

90K 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%

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:

Physical Specifications

Weight:

Dimensions (HxWxD):

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)

18 lbs. (8.2 kg)

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

Magnetic Shielding:

Power Consumption (Average Maximum):

AC Mains Input:

<0.8 Gauss any adjacent surface

45 W

100-240VAC, 50-60 Hz Universal

Many custom options are possible. Call your dealer or

Wohler Technologies to discuss your specific needs.

Audio Response Curve

+10

-10

-20

-30

2k1k50020010050 20k20

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.

10k

AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B

Section 1: General Features and Specifications

Installation

Mounting

The unit should be mounted where convenient for operating persons, ideally at approximately ear level for best high frequency response and eye level for best visual observation of the level meters. Its superior magnetic shielding eliminates concerns about locating it adjacent to most types of CRT monitors, including 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 diagrams on pages 21 and 22 for clarification of the general signal paths into and out of the AMP2A-VTR and AMP2A-VTR2 units.

Electrical Interference

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 undesirable electrical interference in the audio signals.

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.

AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B

Section 2

Operation

Front Panel Features

Rear Panel Features

Audio Amplifier and Speaker Configuration

AMP2A-VTR and AMP2A-VTR2 User Manual P/N 821580 REV-B

Section 2: Operation

Front Panel Features

Please refer to Figure-2a on the following page to familiarize yourself with the front panel features of the AMP2A-VTR and AMP2A-VTR2 units. The following sections describe these features and are referenced, by number, to Figure-2a.

Speakers

All AMP2 Series models feature two mid-range speakers (left and right) and one woofer speaker. Two amplifier/driver 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(s). Note that the woofer channel is NOT a dedicated LFE (subwoofer) or Center channel. See page 14 for more

information concerning the AMP2 Series audio amplifier/speaker configuration.

Power LED

This LED glows GREEN to indicate the unit is connected to mains power and an operation voltage is present.

Audio Level Meter LED Bargraph Displays (1-4)

These four tri-color LED bargraph level meters display audio levels for the four audio signals entering the AMP2A-VTR

unit or, in the case of the AMP2A-VTR2 unit, the four channels selected by the Group Select Switch (Item 10, page 10).

All bargraph LED segments are of the tri-color type (green, amber, red) and are user adjustable for Referrence Level,

Display Mode, Peak Hold, PPM Ballistics, Alternate Bargraph Scales, and Phase Correlation via DIP switches on

the rear panel and inside the unit. For factory set and user adjustable level meter DIP switch settings, see pages 17 and 18.

For more information about the Phase Correlation feature, see page 20. For meter specifications, see page 5.

Volume Control Pot

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 both speaker channels.

Headphone Jack

This jack accepts a standard 1/4” phone type stereo plug. When you plug in headphones, the speakers will mute.

Speaker Assign Channel Buttons (Left and Right)

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 channel selection 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 before releasing it. This will preserve the current

selection set as though the button was never pushed.

Bargraph Brightness Trim Pot

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 the bargraph display LED segments. Adjusting this one control will simultaneously affect

the brightness of all bargraph displays on the front panel.

(Continued)

+ 16 hidden pages

Wohler AMP2A-VTR, AMP2A-VTR2 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual