Front Panel Controls - Grace m 801 Owner's Manual

Front Panel Controls

A 24 position gold contact gain switch
Each gain control has 24 positions and adjusts the
voltage gain from 18dB to 64dB in 2dB steps. For
reference, the 9 o'clock position is 28dB, the 12
o'clock position is 40dB, and the 3 o'clock position
is 52dB.
B bi-color LED peak indicator
The LED peak indicator, which monitors the output
signal, turns green at -14dB and switches to red at
+16dB (12dB before clipping). The threshold level
for peak indication is adjustable on each channel
(see page 8).
C
48V phantom power switch
The phantom power switch (labeled +48V) con-
nects the +48V power supply to pins 2 and 3 on
the XLR input connector. This switch illuminates
red. It should be noted that the LED in this switch
actually monitors the voltage at the input. With no
microphone connected, the LED will continue to
illuminate for approximately 10 seconds after the
phantom power is turned off as the filter capaci-
tors discharge. As well, even if the phantom power
is switched off, the LED will illuminate if voltage is
being fed from an external source. (i.e. when using
a direct split in a remote recording application.)
grace design m801
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owner's manual
A B
1 2
40
30 50 30
20 60
+48V - 20dB ribbon +48V
GRACE DESIGN USA
3
40
50 30
20 60 20
- 20dB ribbon +48V
C
D
phase reversal switch
The phase reverse switch reverses the absolute
polarity of the music signal at the input of the
preamplifier. The switch illuminates green and
provides power for a sealed gold contact relay lo-
cated on the preamplifier circuit board. This elimi-
nates signal wiring to the front panel and switch
contact performance problems.
E
-20 pad switch
The 20dB attenuator switch attenuates the input
signal 20dB. The switch illuminates amber when
engaged. Like the phase reverse switch, this switch
controls a sealed gold contact relay on the pream-
plifier circuit board. With the -20 switch engaged,
the effective gain range becomes -2dB to 44dB.
F ribbon mic mode switch
This switch activates a 10dB increase in overall
preamplifier gain while simultaneously disabling
the 48V phantom power circuit to protect ribbon
microphones. As well, the input coupling capaci-
tors are bypassed.
4
40
50 30
60 20
- 20dB ribbon +48V
D E F
5
40 4
50 30
60 20
- 20dB ribbon +48V -