Two Inputs for CCP
Preamplifers with pre-
polarized Microphones
Two Inputs for Pream-
plifers with externally-
polarized Microphones
Signal Output for
Channel 2
RS232 Control
Input for external
power supply 8 - 18 V
DC
Locking screw for
base plate
Signal Output for
Channel 1
Channel numbers
Adjusments for
Preamplifers with
SysCheck facilities and
externally polarized
Microphones.
G.R.A.S. SOUND & VIBRATION
Power Module Type 12AQ
Page 9
Fig. 2.2 Rear-panel details of the Power Module Type 12AQ
Floating Ouput button
When activated, the output signal of the conditioning amplifier for this channel (via the corre
-
sponding BNC
Output
socket on the rear panel) is set to floating. When cancelled, it reverts to
non-floating.
Polarization 0 V button
Applies to the
Mic
Input
sockets (7-pin LEMO) on the rear panel.
When activated, the polarization voltage for this channel is set to 0 V. When cancelled, it reverts
to 200 V. The polarization voltage is applied to pin 3 (Fig. 2.3).
Preamp . ± 15 V button
Applies to the
Mic
Input
sockets (7-pin LEMO) on the rear panel.
When activated, the supply voltage to the preamplifier of this channel is set to ± 15 V. When can
-
celled, it reverts to ± 60 V. The preamplifier voltage is applied across pins 6 and 7 (Fig. 2.3).
SysCheck button
Applies to the
Mic
Input
sockets (7-pin LEMO) on the rear panel.
When activated, a SysCheck * signal of 1000 Hz is applied to pin 1 (Fig. 2.3) of the
Mic
Input
socket. When cancelled, the SysCheck signal is removed.
2 .2 Rear Panel
Rear-panel details are shown in Fig. 2.2.
* This requires the use of a preamlpifier which can make use of the SysCheck facility, e.g. Type 26AL (¼″) or
Types 26AJ and 26AH (½″).
