User`s manual

2-3
If AUX/Non-sync 2 is used for background music, this is best wired to
the surround input(s) so that it plays to the surround speakers in the
auditorium to prevent the muffling effect of the curtains when these are
closed. If the background music is stereo, then the feeds should be
wired to the two AUX surround inputs. If no second surround card
(Cat. No. 515) is present, the feeds will be summed to mono and sent to
the left surround output. With a Cat. No. 515 present, the surrounds
will appear in stereo.
2.3.2 Remote Fader(s)
If the remote volume control has a resistance of greater than 10K, a
parallel fixed resistor(s) needs to be added to bring the maximum
resistance down to 10K when the pot is at its maximum clockwise
rotation. Bear in mind that although there will be control over the
volume, the fading action will not then match the linear 0-10 scale. For
example, if the pot is 22K linear, then the parallel resistor should be 18K.
For a 47K linear pot, the value would be 13K. Values above 47K are not
recommended.
Bear in mind when installing a remote fader that selection of the remote
will not be possible until pin 2 of the remote connector is grounded.
This is a safety measure to ensure that the local fader resumes control if
the remote becomes unplugged.
2.3.2 Mute
The mute switch on the Cat. No. 516 Remote Unit is a simple locking
pushbutton. Mute is not cancelled by the selection of a format. If format
change muting is required, a simple grounding of pin 13 on the remote
connector during the format change is usually enough to ensure quiet
format changes since, on its own, the mute system takes about 150mS to
restore the volume to its original level when pin 13 ground is removed.
If longer format change muting times are needed then a resistor-capacitor
can be added between pin 13 and pin 4 (ground). The capacitor should
be electrolytic, must have its negative terminal connected to ground (4),
and be 10V or higher. As a broad rule, a 100uF 10V capacitor in series
with 100ohms 20% 1/4W between pins 4 and 13 introduces approximately
a 1 second delay before the volume returns to normal.