Wohler AMP1-DA User Manual

AMP1-DA

1U Audio Speaker Monitor

with Two Selectable AES/EBU Digital Inputs

on BNCs, Two Analog Inputs on XLRs, Stereo

Analog Outputs on XLRs, Two 26-Segment

Level Meters, and Phase Indication

Document P/N 821530 Rev-C

User Manual

CONTENTS

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

Important Safety Instructions and Introduction ..............................................

Section 1: General Features and Specifications .............

Description, Features, and Applications ...................................................

Specifications and Other Options ..................................................................

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 Input D/A Conveter Module PCB Circuit Description ...........................

General Level Meter PCB Descriptions ........................................................

Series II Level Meter Rear Panel DIP Settings ..............................................

Series II Level Meter Internal DIP Settings ...................................................

Series II Level Meter Internal DIP Locations ................................................

Mute on Error Header H12 Location - 919117 PCB ....................................

AMP1-DA 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

AMP1-DA User Manual P/N 821530 Rev-C

General Features

and Specifications

Section 1

Description

Features

Applications

Specifications

Other Options

12/01/06

AMP1-DA User Manual P/N 821530 Rev-C

Section 1: General Features and Specifications

AMP1-DAMP1-D

AMP1-D

AMP1-DAMP1-D

1U Digital/Analog Audio Stereo Speaker Monitor

WOHLER

TECHNOLOGIES

POWER

SOURCE

AVG

AMP1-DA Front Panel

AES

ANALOG

AES1

AES2

DIGITAL

AMP1-DA

DIGITAL AUDIO

MONITOR PANEL

Description

The AMP1 Digital series of audio monitors provides self-powered, full-fidelity stereo monitoring in the smallest rack space possible. All models contain four high performance transducers driven by three power amplifiers: two amplifier/driver combinations handle midrange and high frequency information in stereo, while the third center channel reproduces information below the 500 Hz crossover point.

All AMP1 Digital models come equipped with a ganged stereo volume control and balance pot, power indication LED, and headphone output. Output limiter circuits are incorporated to protect the speakers, and extensive magnetic shielding allows placement immediately adjacent to video monitors without causing display interference.

The AMP1-DA model features two selectable AES input sources on unbalanced BNC connectors and a stereo analog input source on two balanced XLR connectors. A toggle switch on the front panel allows selection of AES source 1 or 2 while another toggle switch selects between the selected AES digital source and the analog source inputs. A red LED indicates the presence and error status of the selected AES signal entering the unit.

Two high-resolution 26-segment tri-color LED bargraph level meters display the audio levels for the left and right selected sources and our proprietary three-LED stereo phase indication feature allows monitoring of phase relationships of the selected stereo inputs. An additional pair of XLR connectors are provided on the rear panel for outputing an analog signal of the selected sources for connecting to downstream equipment.

Features

• 98 dB SPL at two feet

• Only one rack space high

• Audible and visual indication of phase/polarity problems

• Thorough magnetic shielding for placement next to video monitors

• Two selectable AES/EBU inputs on unbalanced BNC connectors

• Analog stereo inputs on two balanced XLR connectors

• Analog output of selected input on two balanced XLR connectors

• AES input signal status indication LED

• AES source selection via front panel toggle switch

• Digital/analog source selection via front panel toggle switch

• Headphone output

• Power indication LED

• Two 26-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 PPM Ballistics (Type I, Type II, DIN 45406, or SSRT)

• Selectable alternate Bargraph Scales (AES, Extended VU,

Alternative AES, VU, BBC, NORDIC, and DIN)

Applications

The AMP1 Digital series is 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., the

AMP1-DA is backed by a strong warranty and a satisfaction guaranteed return policy.

AMP1-DA User Manual P/N 821530 Rev-C

Section 1: General Features and Specifications

General Specifications

Input connectors:

Input impedance:

Input Level for Maximum Output (Volume Full On):

Input Overload:

Peak Acoustic Output (@ 2 ft.):

Response, Sixth Octave:

Power output

ΩΩ

Ω):

ΩΩ

Ω):

ΩΩ

dledle

-distance-distance

dle

-distance

dledle

-distance-distance

RMS Each Side (4 RMS Bass (4

Distortion, Electrical:

Distortion, Acoustic:

Medium-size SegmentsMedium-size Segments

Medium-size Segments

Medium-size SegmentsMedium-size Segments

(f(f

or Midor Mid

or Mid

(f(f

Hum and Noise:

Magnetic Shielding:

or Midor Mid

XLR (3-pin female) 2 each BNC (female) 2 each

XLR (Analog): 40K Ω balanced BNC (Digital): 75 Ω unbalanced

0 dBv balanced

+26 dBv balanced

98 dB SPL

80 Hz - 16 kHz ± 7 dB) (-10 dB @ 50 Hz, 22 kHZ)

10 W transient / 5 W continuous 20 W transient / 10 W continuous

Less than 0.15% at any level below limit threshold

8% or less at worst case frequencies above 180 Hz including cabinet resonance; typically less than 2%

ieie

wingwing

wing

ieie

Better than -68 dB below full output

Less than 1 Gauss any adjacent surface

wingwing

Digital/Analog Specifications

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

AES sampling rate:

D to A converter:

Converted analog out: (S/N):

Converted analog out: (THD):

AES Termination:

+8 = -20, +4 = -20, +6 = -9, 0 = -18 (DIP selectable)

32-48 KHz, auto-select

24-bit low jitter

>90 dB

< 0.008%

Removable (DIP select)

Level Meter Specifications

Level Meter Type:

Bargraph Quantity:

LED Color:

Metering Range:

Reference Level Select:

Display Mode Select:

Peak Hold Select:

PPM Ballistics Select:

26-segment tri-color LED bargraph

2 each, vertical

Tricolor (red, amber, green)

65 dB

0, +4, +6, or +8 dBv

VU Only, VU/PPM, or PPM Only

Manual, 3-sec, 10-sec, or OFF

Type I, Type II, DIN 4506, or SSRT

Power Consumption

(Average Maximum):

AC Mains input:

Physical Specifications

Dimension (h x w x d):

Weight:

35 W

100-240VAC, 50-60 Hz

1.75 x 19 x 12 inches

44.5x 483 x 298 mm

14 lbs. (6.4 kg)

Calibration:

Scale Select:

+10

d B

-10

-20

-30

Typical 1/6 Octave Audio Response Curve

Auto

AES, Extended VU, Alternate AES, VU, BBC, NORDIC, or DIN

Audio Response

10k5k2k1k50020010050 20k20

Other Options

Wohler Technologies offers the broadest range of standard production audio monitor units. Standard-production models or special order custom features for the AMP1 Digital Series (1U) units include the following functions (and combinations thereof):

• SDI (SMPTE259) inputs

• Separate channel volume controls

• Mono, mute, and mode switches

• Alternate level meter scales and color maps

• Transformer coupled analog inputs

• FULL output power DC operation

• External speaker capability

• Multiple input and output connector type choices

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

Units are designed to meet, at time of manufacture, all currently applicable product safety and EMC requirements, such as those of UL and CE. 0 dbV ref. 0.775V RMS. Features and specifications subject to improvement without notice.

AMP1-DA User Manual P/N 821530 Rev-C

Section 1: General Features and Specifications

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.

NOTE: Be sure to set the level meter Input Level Gain Calibration and VU/PPM Display Mode DIP switch (accessed through the top cover) BEFORE installing the unit into an enclosed rack or console. See page 17 for setting information.

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 20 and 21 for clarification of the general signal paths into and out of the AMP2A and AMP2A-2S units.

Analog inputs via the 3-pin female XLR connectors are configured for 200K Ω balanced connections. RCA connector inputs (AMP2A only) are configured for 47K Ω unbalanced connections.

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.

As with any audio equipment, maximum immunity from electrical interference requires the use of shielded cable; however, satisfactory results can sometimes be obtained without it. The internal circuitry common is connected to the chassis.

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.

AMP1-DA User Manual P/N 821530 Rev-C

Audio Amplifier and Speaker Configuration

Balance Control Characteristics

Section 2

Operation

Front Panel Features

Rear Panel Features

AMP1-DA User Manual P/N 821530 Rev-C

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 AMP1-DA unit. The following sections describe these functions and are referenced, by number, to Figure-2a.

Speakers

The AMP1-DA internal speaker system is comprised of two mid-range tweeter speakers (left and right) and two woofer speakers (left and right). The two mid-range speakers reproduce, in stereo, only the mid and high frequencies, while the two woofer speakers monorally reproduce the low frequencies. See page 14 for more information about the speaker configuration of the AMP1 Series.

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.

Headphone Jack

Select the headphone audio sources as you would for the internal speakers. When you plug in headphones, the internal speakers will mute. This jack accepts a standard "mini" stereo (ring/tip/sleeve) plug.

Power Indication LED

This LED glows green to indicate the unit is connected to operational mains power.

Phase Indication LEDs

These three LEDs offer instant visual verification of phase (polarity) conditions in the pair of channels selected for monitoring in the

ΦΦ

Left/Right channel speakers. The two smaller LEDs, labeled in the signal, while the larger center LED, labeled AVG, indicates the average phase condition.

The small top for out-of-phase signals. The larger AVG LED indicates the average phase condition by glowing GREEN for in-phase conditions, or RED for out-of-phase conditions.

In general, it is sufficient to regard the AVG LED (average phase condition) as adequate for proper phase monitoring. While it is normal for stereo signals to contain some intermittant instantaneous out-of-phase and in-phase conditions (small LEDs), a steady red glow of the larger LED almost always indicates an out-of-phase alarm condition.

ΦΦ

Φ+ LED glows (or blinks) GREEN when signals are in-phase. The small bottom

ΦΦ

Φ+ and

Φ- (above and below), show instantaneous phase relationships

ΦΦ

Φ- LED glows (or blinks) AMBER

ΦΦ

Audio Level Meters

Audio levels for the selected input sources are displayed via these two 26-segment tri-color (GREEN, AMBER, RED) LED bargraph display level meters.

These two bargraph displays feature an Auto-Calibration feature and are user adjustable for Display Mode and Reference Level via a rear panel DIP module (Item F, page 12). Peak Hold, PPM Ballistics, and Alternative Scales can be set via an internal DIP module. See pages 18 and 19 for more information regarding these DIP switch module locations and settings.

AES/EBU Signal Status Indication LED

This LED indicates the status of the currently selected AES digital signal (AES1 or AES2) regardless of any other monitor selection settings.

This LED glows GREEN as long as a valid AES digital datastream is being received. It will glow RED to indicate errors in the reception of the AES signal. There are two DIP switch selectable modes of fault detection that will create a RED LED error indication. Please see Item B, page 10 for more information about this setting.

An additional 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 21 for location of H12 on the 919117 PCB.

Digital Source Select Switch

This switch selects between the two AES/EBU IN (IN1 or IN2) source inputs (Item C, page 10). Note that for the selected AES source to be monitored, the Analog/Digital Source Select Switch (Item 9) must be set to DIGITAL.

Analog/Digital Source Select Switch

When this toggle switch is set to ANALOG, the unit will monitor the analog input signals from the ANALOG IN XLR connectors on the rear panel (Item G, page 14). When this toggle switch is set to DIGITAL, the unit will monitor the selected AES/EBU IN input (IN1 or IN2) on the rear panel (Item C, page 10).

Balance Control

This pans the volume balance between the left and right speakers. See page 14 for more information about the balance control characteristrics of the AMP1 Series.

Bargraph Brightness Adjust

This control is recessed into the front panel and can be accessed using a small flathead screwdriver. Turning the trim pot clockwise will simultaneously increase the relative brightness of the LED segments in both bargraphs.

+ 16 hidden pages

Wohler AMP1-DA User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual