Studio Technologies 68 V.1 - Manual (Page 14)

Issue 2, June 1999 Model 68/69 User Guide
Page 14 Studio Technologies, Inc.
for Surround
optimal unbalanced operation, it is impor-
tant to connect both – and shield together
directly on the D-sub, and not at the other
end of the harness.
Note that while the Model 68’s electroni-
cally balanced output circuits are capable
of driving loads of 600 ohms or greater,
the output level will drop slightly as the
load impedance approaches 600 ohms.
A 0.5dB difference in output level can be
expected as the load impedance changes
from 10k ohms to 600 ohms.
Be aware that whenever the L/R Bypass
function is enabled, the Model 68’s left and
right output circuitry is disabled, and the
L/R Bypass inputs are routed directly to
the left and right monitor output connec-
tions. Ensure that the source of the L/R
Bypass signal is capable of correct opera-
tion with the wiring scheme selected.
Remote Control Inputs
Support is provided for four remote control
functions: Remote Mute All, Remote Dim,
Remote L/R Bypass, and Remote Input
Select. The four inputs use logic gates,
“pulled up” to +5V by way of resistors,
which are active when brought to the logic
low state. (Inputs of this type are com-
monly referred to as GPI inputs.) While
the input circuitry is protected from over-
current and static (ESD) discharge, care
should be taken to prevent nasty signals
from reaching them. The inputs are active
only when held in the low state; they can’t
be configured to change state (“latch”) in
response to a logic pulse.
The connector labeled REMOTE CON-
TROL on the back panel of the Model 68
is used to interface the four remote control
inputs. Refer to Figure 7 for exact connec-
tion details. Note that pin 1 (shield) and pin
9 (remote control common) are electrically
identical. In addition to connecting to
system common, they connect to the
Model 68’s chassis and mains earth con-
nections. For convenience, the shield of
the interconnecting cable should be con-
nected to pin 1 (shield), while the return
signals of the remote control sources
should connect to pin 9 (remote control
common).
Note that although the remote control
connections are physically made to the
D-sub on the Model 68’s back panel, the
remote control input circuitry is actually
located in the Model 69 Control Console.
Four conductors in the cable linking the
Model 68 to the Model 69 route the remote
control signals to the actual input circuitry.
Connecting the Model 69
to a Model 68
A cable with 9-pin D-sub plugs (males)
on each end is used to interconnect
the Model 69 Control Console with the
Model 68 Central Controller. A 20-foot
(6.1-meter) cable is provided with each
system. The connector labeled TO/FROM
Pin Signal
1 Shield
5 Remote Mute All
6 Remote Dim
7 Remote L/R Bypass
8 Remote Input Select
9 Remote Control Common
Notes: 1) Connector type on Model 68 is 9-pin D-subminiature
female. Connector uses 4-40 threaded inserts for
locking with mating plug.
Figure 7. Connector Pin Out for Remote
Control Inputs