Audio Developments AD144 - Manual (Page 41)

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The mono signal to COMM 2 is selected by an 11-way rotary switch (9) - posn 1 is a
mono mix of the signal to COMM 1; posn 2 is a mono mix of the signal appearing on
the monitor modules; posn 3 is a mono mix of the signals selected by MON on the
channel modules; the remaining positions select the 4 output signals and the 4
auxiliary signals. Output level is controlled by potentiometer (22).
The mono signal to COMM 3 is selected by MON TO COMM 3 (10) - either a mono
mix of the signal on COMM 1 or a mono mix of the signals appearing on the monitor
modules. Output level is controlled by potentiometer (23).
1k MARK - non-latching (12) - mixes, simultaneously, a 1kHz tone onto the 4 main
and 4 auxiliary mix busses.
TAPE (with LED indicator) is a latching switch (13) for remote starting a tape recorder.
On release of SW (13) a brief 1kHz tone is mixed onto the 4 main and 4 auxiliary
busses. These marker tones may be disabled in pairs - A/B, C/D, Aux1/2, Aux 3/4 -
by transfer of the moveable shorting links located at the lower end of the module’s
main printed circuit board.
[The 1kHz marker tone and internal microphone may be mixed, simultaneously, to the
main and auxiliary mix busses.]
ON AIR (with LED indicator) is a latching safety switch (14) that prevents the use of
marker tone and the internal microphone during programme.
The internal microphone may be slated, under the control of SW (14), to A.B (15), C.D
(16), A1/A2 (17) and A3/A4 (18) & L/R (28).
AD144 permits the operator to remotely control five external devices - one of them via
TAPE - SW(13) - on the communications module, and the others by end-of-fader
switches on four modules. The position of these modules will have been specified at
the time of order and detailed in the CUSTOMER NOTES & FACTORY
MODIFICATIONS section of the manual. For safety reasons the five control lines are
isolated from the mixer by relays. A label on each printed circuit board indicates
which relay the particular module drives in order that, at a later date, the position of
these modules may be changed within the frame.
The use of these control lines is not restricted to switching tape recorders on/off.
They can, for instance, switch on tally lamps - of less than 50v DC - or switch off
monitor loudspeakers. If pins 3-7 on the ‘D’ connector are connected together,
operation of TAPE (13) or opening any of the faders fitted with switches will activate a
tape recorder. If pins 3-6 are connected together, it can be arranged that opening any
of the faders would switch off a pair of monitoring loudspeakers. These are but two of
the many ways in which the five control circuits can be arranged.