© 2006 Wohler Technologies Inc. ALL rights reserved
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VMDA Series User Manual P/N 821115 Rev-C.5
Please refer to Figure-1a on the following page to familiarize yourself with the front panel controls and indicators
of the VMDA series units. The following sections describe the functions of each of the various controls and
indicators found on the front panel and are referenced, by number, to Figure-1a.
1 Speakers
The VMDA series internal speaker system is comprised of two mid-range tweeter speakers (left and right) and one
compact woofer speaker (center). Speaker amp limiters prevent accidental damage to the speakers due to excessive
input levels.
2 Volume Control
This controls the loudness of the audio reproduced by the internal speakers or connected headphone.
3 Audio Level Bargraph Meter Displays
Audio levels for the selected source channels are displayed via two 10-segment LED bargraph meters (one on the
left side of the front panel; one on the right side). Dynamic range for these meters is 23dB.
Contact the factory for additional meter information concerning meter scales and ballistics.
4 Channel Select Buttons (VMDA-4 Only)
These four buttons select which channel(s) will be monitored through the speakers and are labled 1 through 4.
When monitoring analog signals it is possible to monitor from one to four stereo pairs. When monitoring two,
three, or four analog stereo pairs, the channel pairs are summed together and are reproduced simultaneously
from the left and right speakers. However, when monitoring digital signals, only one stereo pair at a time may be
monitored. An LED in each button lights up to indicate which channel(s) are selected for monitoring.
5 Headphone Jack
For critical listening or for listening in high noise environments, use the headphone feature rather than the
internal speakers. Select the headphone audio sources as you would for the internal speakers. When you plug in
headphones, the internal or external speakers will mute. This jack accepts the standard 1/4” phone type stereo
plug.
6 Power Indicator LED
The Power Indication LED signals the operating condition of the power supply. The LED glows green to
indicate the unit is connected to mains power and an operation voltage is present.
7 Balance Control
This pans the volume balance between the left and right speakers.
8 Input Select / Speaker Mute Button
This button serves a dual function; it selects between the two input signal types (digital AES/EBU or analog) and
also toggles the speaker mute feature on and off.
Source Select:
The button exhibits a steady green glow to indicate that the unit is monitoring the digital inputs
and the button is unlit when indicating that the unit is monitoring the analog inputs. To toggle between the digital
and analog source types, the button is depressed for one second.
Mute:
To mute the speakers at any time, the button is briefly tapped once, the button blinks to indicate it is in mute
mode. A second single tap unmutes the speakers.
FRONT PANEL CONTROLS AND INDICATORS
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