KR2600 is a Stereo Receiver and internal Power Amplifier inside, made by KENWOOD at 70s. It using symetrical supply 30VDC and its also can deliver power audio 15 Watts RMS.
The Power Amplifier section consist of differential pre-amplifier, Voltage Amplifier Stages, Servo Driver, Driver Amplifier and Power Amplifier.
Some interesting on the schematic is it has an internal tone control that using feedback from the Power Output.
SCHEMATIC DIAGRAM
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Differential pre-amplifier are using transistor Q1 &Q2 ( A763 ).
The output of Q1 then going to Q4 for Voltage Amplification.
VAS transistor Q4 are using 2SCC1213, and also there are Resistor limiter and Bypass Capacitor 100uF.
RV1 set to make stationer current for The Power Amplifier Transistor.
You can modifying NTC RT1 or remove it from your cloning kit, but you must adapt some value for bias transistor servo driver Q5.
Pairing Transistor C789 and A489 are 30Watt at Dissipation Power maximum ( DATASHEETS ).
Tone Control section is paralell connection with feedback resistor R8 ( 120K ) for make better tone controlling. Its start with C16 ( 10uF ) at the output of Power Amplifier and finish at C10 ( 10uF ).
