Prefiguration of the not-so-well remembered SA-1000 mammoth and probably quite a “sleeper” as such.
Still a bit hectic inside… and with only two (big) smoothing caps instead of four, but the heatsinks are the same, so is the RF varicap and so are most of the (many) functions.
• DC full complementary OCL circuit
• Each differential amp uses a single-package dual-transistor (A798 56F) with a 100% DC feedback circuit.
• Emitters/followers follow the differential first stage.
• Pre-driver stages are constant-current loaded Class A amplifiers.
• Parallel push-pull output.
• Multiple protection circuits with overload alarm
• Low-noise, overload-resistant phono EQ section.
• First stage is a differential amp with current mirror load.
• Second stage is low-distortion Class A amp which drives the SEPP output circuit with low impedance.
• Detented volume control with 26 2dB steps
• Low distortion tone controls with three-stage DC circuit and tabilized differential amplifiers (1st stage) and SEPP output (final stage)
• 4-gang dual-gate MOS-FET Mixer with point-to-point wiring in the FET buffer-equipped local oscillator
• Flat group-delay ceramic filters with 6 stages of differential amplification by way of constant-current supply and three ICs and discrete stages
• Independent IF control circuit, high-linearity detector with select detector diodes
• FM MPX PLL IC with double-differential