User manual

AMP2-DA Instruction and Service Manual P/N 821505 Rev-B

Please refer to Figure-2a on the following page to familiarize yourself with the front panel features of the AMP2-DA unit. The

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

Section 2: Operation

Front Panel Features

(Continued)

Speakers

The AMP2-DA internal speaker system is comprised of two mid-range tweeter speakers (left and right) and one woofer

speaker (middle). The two side channel speakers reproduce, in stereo, only the mid and high frequencies. Please note that

the woofer speaker (middle) is not a dedicated Center nor LFE speaker.

Power Indication LED

This LED glows green to indicate the AMP2-DA is connected to mains power and an operation voltage is present.

Audio Level Meter Bargraph Displays

Audio levels for the selected source (left and right) are visually displayed via these two high-resolution, 53-segment, tri-

color (red, amber, green) LED bargraph display level meters. Bargraph 1 monitors the left channel while bargraph 2 monitors

the right channel. Dynamic range for these meters is 65 dB and they are able to display signal levels using either PPM or VU

standards with a choice of ballistic behaviors. Alternate display modes are user selectable via two DIP switch modules

accessible through the top cover of the AMP2-DA. See page 22 for a description of the Bargraph Display Mode and Meter

Input Gain Calibration settings.

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.

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 1/4” phone type stereo plug.

Analog/Digital Source Select Switch

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

When this toggle switch is set to ANALOG, the unit will monitor the analog signals from the ANALOG IN XLR connectors

on the rear panel (Item F, page 16). When this toggle switch is set to DIGITAL, the unit will monitor the selected channel

of the AES/EBU IN BNC connectors (1 or 2) on the rear panel (Item C, page 14).

Bargraph Brightness Adjust 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

brighness of both bargraph displays on the front panel.

Phase Indication LEDs

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

the Left/Right channel speakers. There are three LEDs; the two smaller LEDs labeled FAST (left side of the PHASE section)

show instantaneous phase relationships in the signal, while the larger LED, labeled "AV G " (right side of the PHASE section),

will indicate the average phase condition. The small FAST LED on the left glows (or blinks) green when signals are in-

phase. The small FAST LED on the right glows (or blinks) amber for out-of-phase signals. The larger AV G 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 AV G LED (average phase condition) as adequete for proper phase monitoring. While it is normal for

stereo signals to contain some intermittant instanateous 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.

Balance Control Pot

This pans the volume balance between the left and right speakers (or headphones).