Specifications

Adjusting ”Off” Attenuation
In instances when the number of microphones in use is high, it may be necessary to increase the
amount of “off ” attenuation per microphone to keep the total ambient noise level low. There are
“off ” attenuation adjustments inside the unit. To adjust the “off ” attenuation of channel 1,
unplug the unit, remove the top cover and locate the trimpot designated on the circuit board by
“VR102” (Figs. 3 and 4). It is factory set at approximately 8 dB, the attenuation at the middle of
the control’s rotation. When the control is turned fully counter-clockwise, “off ” attenuation is
approximately 20 dB. Conversely, when the adjustment is turned fully clockwise, “off ” attenua-
tion is approximately 6 dB. VR202, VR302 and VR402 control “off ” attenuation for channels 2, 3
and 4 respectively.
Figure 3. Internal view of mixer.
Figure 4. Detail of internal controls.
Don't Touch !
Rear Panel
Output Level LED Meter
The Output Level LED meter is factory set
to indicate RMS output. Should peak output
indication be desired, simply unplug the unit,
remove the top cover and change the setting
of the switch designated on the circuit board
by “S602” (Figs. 3 and 4). “Zero” (0) level is
factory-calibrated at +4 dBm into 600 ohms.
8
MIC
LINE
PEAK
RMS
OUTPUT ATT
METER RESPONSE
S501
LINE
MIC
INPUT ATT
S401
LINE
MIC
INPUT ATT
S301
ON
OFF
PHANTOM
S402
S602
-10dB
0dB
PAD
S403
-10dB
0dB
PAD
S303
-10dB
0dB
PAD
S203
-10dB
0dB
-6dB-20dB
PAD
S103
VR102
ON
OFF
PHANTOM
S302
LINE
MIC
INPUT ATT
S201
LINE
MIC
INPUT ATT
S101
ON
OFF
PHANTOM
S202
ON
OFF
PHANTOM
S102
GATE ATT
-6dB-20dB
VR202
GATE ATT
-6dB-20dB
VR302
GATE ATT
-6dB-20dB
VR402
GATE ATT