Telex Q II - FOH THE AUDIO MASTER MODULE, Q2 TECHNICAL DESCRIPTION

Q2 OPERATION AND MAINTENANCE MANUAL 9601 62
This consists of two main boards and one sub board. The sub
board carries the balanced tape inputs, balanced mix outputs,
balanced Left, Centre and Right monitor outputs and the Left AFL
Meter. The tape signals are fed down to the audio master board
while the mix and monitor outputs are fed in to the sub board from
the master board.
The main audio board carries the Right AFL meter and the main
circuitry for the Left, Centre and Right outputs of the console in
addition to the monitoring functions.
Typically the signal path from the left mix bus to the mix output is
as follows. The signal from the LEFT bus is mixed in a virtual
earth amplifier and immediately after this the LMIXPRE signal is
taken to other parts of the circuit. The signal then passes through
an SSM2404 switch which operates as a changeover to allow SIP
signals onto the signal path in place of the mix signal. Following
this an SSM2142 is used to send a balanced insert send signal to the
send jack which is normalled to the return jack. From here the
signal passes through an SSM2143 balanced to unbalanced stage to
the main fader (one each for Left Centre and Right). A fader buffer
stage follows after which the signal is fed up to the sub board to the
main mix outputs of the console. The signal is known as LMIX at
this point. A further buffer stage follows and the signal is then
known as LEFTMIX which goes to the matrix link connector. The
MIXL signal, in addition to going to the sub board connects to the
PRE switch which allows either a mix pre or post fade signal to be
selected as the source for the centre mix when mix left and right are
assigned to it. The combined signal is fed onto the CMIX bus.
The Left Right and Centre PRE signal derived immediately after
the mix amplifiers is used for SOLO and PFL and is fed via
SSM2404s onto the solo buses. A switch selects PFL or AFL
operation while a further switch located towards the top of the
module is used to select SIP operation. The output of the PFL/AFL
switch feeds the AFL meters which are mounted on the module
before entering the monitoring system via an SSM2404. A SOLO
TRIM pot can be used to alter the PFL solo level although it will
not of course change the level shown on the meter. The external
feeds to the meterbridge are permanently tied to the mix outputs of
the console.
THE AUDIO
MASTER MODULE
Q2 TECHNICAL DESCRIPTION