Specifications
Channel board near integrated circuit U105 [see Figure
271.
3. ~nsolder the jumper at XI
04
and solder
it
or a new
jumper in the holes of
XI
03.
4.
Reassemble the Channel board and top cover as
described above.
Mute Action to Inhibit Action
As supplied, a channel will mute when the Mute In terminal is
grounded. After this modification, grounding the Mute In ter-
minal will not affect the channel if it is already "on", but it
will
prevent the channel from gating "on" from the "off"
condition. The modification is required for the "Filibuster"
mode previously described, and for any logic
terminal use re-
quiring connection of a channel's Gate Out terminal to its
Mute In terminal.
1
.
Remove the top cover and Channel board to be modified
as described above.
2. Locate jumper
XI 05 and jumper holes XI 06 at the
bottom front of the board [see Figure
271.
3. Unsolder the jumper at XI05 and solder
it
or a new
jumper in the holes of
XI 06.
4. Reassemble the Channel board and top cover as
described above.
EHANNEL BOARD A1: X103-XI06
FIGURE
27
Gated Direct Out
In contrast to the external wiring additions described under
Direct Out Gating [see Logic Functions], this modification
applies the internal gated microphone signal to the Direct
Out Jack while retaining the optimized decay characteristics
and avoiding the need for a separate power supply. It does,
however, remove the modified channel's gating from the
mixed output, and thus does not provide automatic gain ad-
justment for the number of open microphones.
1. Remove the top cover and the Channel board to be
modified as described above.
2.
Locate and remove resistor R119 and the wire jumper
physically located between
R119 and capacitor C118
[see Figure 281.
3.
Solder a wire jumper between the hole closest to the
printed marking
"R119" and the now-empty jumper
hole closest to it.
4.
riel
t
iuue resistor R101 [near the Direct Out jack] and
replace it with a
5.6k, 5% resistor.
5.
Reassemble the Channel board and top cover as
described above.
6. NOTE: With this modification, the Direct Out jack now
provides a gated signal for that channel only. The signal
is high impedance
[2.8k to 5.6kl and unbalanced, with a
nominal signal level of -24
dBV [60 mV] for 74 dB SPL
with the Channel Gain control centered.
It
will vary
directly with the Channel Level control. This is equivalent
to a typical aux
level signal. To obtain a low-impedance
balanced,
mic-level output, plug in an impedance match-
ing transformer [Shure
A95U or equivalent]. The
nominal level then becomes -48
dBV [4 mV].
BEFORE AFTER
DIRECT GATED OUTPUT CONVERSION
FIGURE
28
Direct Out to SendlReceive Jack
AMS Direct Out jacks can be modified to function as
sendlreceive jacks for use with equalizers, limiters, voltage-
controlled amplifiers, or other external devices. With the
modification, the microphone output signal is present on the
tip terminal of
J101, and the return input signal is on the
ring terminal. The modified output signal has a nominal level
of -37
dBV at 74 dB SPL [I 7 dB higher than the unmodified
Direct Out signal level], with a maximum level of
+
17 dBV at
1 28 dB SPL. The patch point is before the Channel Gain con-
trol [pre-fader] and before the microphone gating [ungated].
The external device should be a nominally unity gain circuit,
with an input impedance of
10k or greater. The load im-
pedance it sees at the ring terminal will be 5k to 1
Ok, de-
pending on the Channel Gain control setting. Consult the pro-
cessing device manufacturer's literature for proper applica-
tions within these
level and impedance limits.
1. Remove the top cover and Channel board to be modified
as described above.
2. Locate,
unsolder and remove resistors Rl 01 and
R104 and jumper
XI07 on the Channel board [see
Figure
291.
3.
Solder a wire jumper between the XI07 solder hole
farthest from the edge of the board
and one of the
solder holes
between
the now-removed Rl 01 and
R104 resistors.
4. Locate point
Z
on the Channel board [ring terminal of
J1 01
1,
and solder a jumper between it and the remain-
ing [board edge] solder hole of
XI 07.
5. For circuit continuity when a processing device is
not
connected to the modified Direct Out jack, wire the
jack's tip and ring switching terminals together. [These