THE AUDIO
MASTER MODULE
Q2 TECHNICAL DESCRIPTION
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.
Q2 OPERATIONAND MAINTENANCE MANUAL 9601 | 62 |