Wohler AMP2-DA, AMP2-AVU, AMP2-APP User Manual

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 Mechanical

VU (AVU) or PPM (APP) Level Meters,

and Phase Indication

Document P/N 821584 Rev-A

User Manual

CONTENTS

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

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

Balance Control Characteristics .............................................................

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

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

AES to Analog Converter 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 .............

ECO-2551 (08/13/04)

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

AMP2-DA/AVU and AMP2-DA/APP User Manual P/N 821584 Rev-A

Section 1

Features, Specs, and Installation

Description

Features

Applications

Specifications

Installation

Sect. 1: General Features and Specifications

AMP2-DA/AVU and AMP2-DA/APP User Manual P/N 821584 Rev-A

Section 1: Features, Specs, and Installation

AMP2-DA/AVU

and

AMP2-DA/APP

Powered Audio Monitors

AMP2-DA/APP Series Front Panel

Description

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.

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

• Choice of either VU

• Two selectable AES/EBU inputs on unbalanced BNC connectors

or PPM high quality mechanical level meters

• 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

AMP2-DA/AVU and AMP2-DA/APP User Manual P/N 821584 Rev-A Section 1: Features, Specs, and Installation

Applications

The AMP2-DA/AVU and AMP2-DA/APP 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

Input Connectors:

Analog Input Impedance: Digital Input Impedance:

Peak Acoustic Out (@ 2 ft.):

Power Output,

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:

Converted Analog Out S/N:

ΩΩ

Ω):

ΩΩ

Ω):

ΩΩ

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 0.15% 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

Digital AES Specifications

AES termination:

AES sampling rate:

D to A converter:

D to A gain calibration, (dB = dBFS):

75Ω (ohm) removable, unbalanced

32-48 kHz, auto-select

18-bit low jitter

DIP switch selectable; 0 = -18, +6 = -9, +4 = -20, +8 = -20

Physical Specifications

Weight:

Dimensions (HxWxD):

* Optional XLR connectors (instead of BNC) may be specified for the AES inputs at the time of order.

Note: See page 21 for level meter specifications.

18 lbs. (8.2 kg)

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

Converted Analog Out THD:

Magnetic Shielding:

Power Consumption (Average Maximum):

AC Mains Input:

+10

-10

-20

-30

<0.008%

<0.8 Gauss any adjacent surface

45 W

100-240VAC, 50-60 Hz Universal

Audio Response Curve

Typical 1/6 Octave Audio Response Curve

2k1k50020010050 20k20

10k

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.

AMP2-DA/AVU and AMP2-DA/APP User Manual P/N 821584 Rev-A

Section 1: Features, Specs, and Installation

Installation

Mounting

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

AES/EBU digital inputs are via female BNC connectors and are configured for 75 Ω unbalanced connections. Analog inputs are via two 3-pin female XLR connectors and are configured for 70K Ω balanced connections. 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 corruption of the digital datastream.

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.

AMP2-DA/AVU and AMP2-DA/APP User Manual P/N 821584 Rev-A

Section 2

Operation

Front Panel Features

Rear Panel Features

Audio Amplifier and Speaker Configuration

Balance Control Characteristics

AMP2-DA/AVU and AMP2-DA/APP User Manual P/N 821584 Rev-A

Section 2: Operation

Front Panel Features

Please refer to Figure-2a on the facing page to familiarize yourself with the front panel features of the AMP2-DA/AVU and AMP2- DA/APP units. The following sections describe these features and are referenced, by number, to Figure-2a.

Speakers

The monitor features 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 16 for more information concerning the AMP2 Series audio amplifier/speaker configuration.

Audio Level Meters - Mechanical

Audio levels for the left and right sources selected for monitoring are respectively displayed in the left and right mechanical level meters. The AMP2-DA/AVU model uses meters exhibiting VU ballistic characteristics. The AMP2-DA/APP model uses meters exhibiting PPM ballistic characteristics. See page 21 for Threshold Level adjustment and settings for the VU and PPM type of meter.

Analog/Digital Source Select Switch

This two position toggle switch allows the operator to choose between two primary input sources; ANALOG or DIGITAL

• ANALOG = Unit will monitor the analog signals as input on the rear panel ANALOG IN XLR connectors (Item F,

page 14).

• DIGITAL = The 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) must be set to DIGITAL.

AES Status LED

This bi-color (GREEN/RED) LED indicates the status of the selected AES input signal (1 or 2) and functions regardless of whether the analog or AES inputs are selected for monitoring. LED indication is as follows:

• GREEN = a valid AES/EBU digital datastream is being received

• RED = there are errors in signal reception and/or data errors (if the data has been tagged as inappropriate for

conversion to analog by having the validity bit set).

Note: The AES Termination and Error Indication Type DIP switch module on the rear panel (Item B, page 12) is used to set this LED to indicate either reception and data errors or to indicate reception errors only.

An optional feature of the AES signal error detection is the ability to mute the audio when errors are detected in the AES signal. To enable this feature, a jumper is placed at H12 of the 919117 PCB. See page 20 for location of H12 on the 919117 PCB.

Headphone Jack

This jack accepts a standard 1/4” phone type stereo plug. Select the headphone audio sources as you would for the internal speakers. When you plug in headphones, the speakers will mute.

Volume Control

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.

Power LED

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

(Continued)

+ 16 hidden pages

Wohler AMP2-DA, AMP2-AVU, AMP2-APP User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual