Here exist the input circuits of two channels and input of microphone channel. The two basic channels she is same between them. Thus that its go for a channel, the he is also go for the other.
In each stereo channel exist two inputs, classic stereo input PHONO that is practical a correction filter RIAA and concerns the signal amplification of sound that emanates from the classic reproduction heads of classic disks LP. Exist also a stereo input of LINE high level for signals that emanate from CD players, Tuners, DVD, etc. The exits of this two stages are selected with switch S1 or S2 and they are applied in the next stage which is constituted from adder IC3. Here is regulated the BALANCE with the RV5 and GAIN with the RV1. In the next stage round the IC4 exist a classic 3-band regulation of tone circuit, the regulation of which becomes with the RV2-3-4. The exit of IC4 drive the RV6 that is at preference pontesometer [FADER]. By points 1-2-5-6 the signals connected to next stage [Fig.2]. In the Fig exist also the microphone input, which is in electronic Balance connection, round the IC9A. Here exist the regulation of GAIN with the RV13. It follows a stage of tone two-band regulation, round the IC9B and a stage of parametric regulation of mid band with RV16 [Gain] and RV17 [Frequency Band]. With the RV19 we regulate VOLUME [FADER] and with the RV18 we regulate the BALANCE. By points 9-10-11 the signal is connected to the corresponding points.
Visit Here for more.