CIRCUIT DESCRIPTION
THEORY OF OPERATION
AS SHOWN IN THE BLOCK DIAGRAM, THIS MIXER HAS 5 INPUTS AND 3 OUTPUTS.
THE DC 15V POWER SUPPLY ENABLES THE 18V/AC ADAPTOR TO BE CONVERTED TO ±15V
/DC AND IS USED TO FEED THE IC OF EACH STAGE AND LAMP OF THE VU METER.
THE MIC SIGNAL FROM INPUT JACK THROUGH MIC AMPLIFIER (IC2 IS A LINEAR AMP-
LIFIER) MAGNIFICATION, THEN SEND TO THE MIC LEVEL CONTROL(VRl), AFTERWARD,
THE MIC SIGNAL IS SEND TO THE MIXING BUS. AND THE PHONO l(IC3.VR2)/PHONO 2
(IC4/VR3) LIKEWISE. (IC3/IC4 IS A MATCH TO RIAA CURVES UNLINEAR AMPLIFIER)
THE SIGNAL OF CDl/VIDEO FROM INPUT JACK IS DIRECTLY SEND TO THE LEVEL CON-
TROL(VR4), THEN SEND TO THE MIXING BUS. AND CD2/LINE LIKEWISE.
THE SIGNAL OF MIXING BUS GOES TO THE WEIGHTED SUMMING AMPLIFIER(IC6) AND
THEN ON TO THE MASTER GAIN STAGE(IC1) MAGNIFYING IT WHICH RESULTS AS OUT-
PUT GOING TO THE REC OUTPUT JACKS AND THE MASTER OUTPUT STAGE (IC5), AND
THE MASTER OUTPUT STAGE(IC5 IS A LINEAR AMPLIFIER) SEND THE OUTPUT SIGNAL
TO THE OUTPUT JACKS.
THE SIGNAL COMING FROM THE MASTER OUTPUT STAGE(IC5) GOES THROUGH THE VU
METER AMPLIFIER(IC7), WHICH IS THEN SHOWN ON THE VU METER.
THE SIGNAL(PRE-FADE) OF EACH CHANNELS GOES
THROUGH THE
MONITOR
SELEC
T swI-
TCH (ROTARY SWITCH SW1)WHICH IS THEN TRANSMITTED TO THE HEADPHONE AMPLIFI-
ER(IC8) & MAGNIFIED,THEN GOES TO THE HEADPHONE JACK.
