636S & 637S is a receiver with internal power amplifier inside. The power are using OCL amplifier and supply 60VDC asimetrically. Its product by SCOTT at end 70s.
INFO
Inside of 636S.
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SCHEMATIC
This is an edited schematic diagram of 636S power amplifier section.
The schematic is quite simple with just only 6 transistor inside the power amplifier section.
NOTE
2SD201 power transistor able to produce until 50W output ( SOURCE ).
