Technics - SU-3500 Solid state integrated amplifier

Technics SU-3500 integrated stereo amplifier from the very top of Matsushita’s early golden years (circa 1975–1977). In 100% good working order and in very tidy vintage condition, with light signs of use consistent with its age.
For enthusiasts of classic Japanese industrial design and serious audio engineering, the SU-3500 is an iconic model. The unit weighs over 10 kilograms and features a substantial, thick brushed-aluminum front panel with beautifully machined knobs and solid toggle switches. Under the hood is a fully discrete design with a large, shielded transformer and a direct-coupled OCL power amplifier.
Sonically, this amplifier is known for its exceptionally stable, warm and uncolored sound, with notably fast, tight bass and a very low noise floor. Of particular interest to vinyl enthusiasts is the dual phono circuit: the SU-3500 has two phono inputs with adjustable input resistance and capacitance (impedance selector), allowing different cartridges to be matched precisely. In addition, the tone controls offer selectable turnover frequencies (turnover switches) and a dedicated defeat setting to keep the signal path as pure as possible. The pre-out/main-in connections on the rear panel also allow the preamp and power amp sections to be used completely separately.
Specifications
Type: Integrated stereo hi-fi amplifier
Model: Technics SU-3500
Year of manufacture: circa 1975–1977
Continuous output power: 2 x 41 watts RMS into 8 ohms (2 x 43 watts into 4 ohms), with both channels continuously driven
Frequency response: 5 Hz–100,000 Hz (+0 / -3 dB, Main In), 20 Hz–20,000 Hz (Phono RIAA ±0.3 dB)
Total harmonic distortion (THD): 0.08% at rated power
Intermodulation distortion (IMD): 0.08%
Damping factor: 50 (8 ohms)
Signal-to-noise ratio: 70 dB (Phono), 90 dB (Line/Tuner/Aux)
Phono input capacitance and resistance: Phono 1 (47 kOhms), Phono 2 (selectable: 25 kOhms, 60 kOhms, 100 kOhms)
Tone controls: Bass (±10 dB at 50 Hz, turnover: 250 Hz / 500 Hz), Treble (±10 dB at 20 kHz, turnover: 2.5 kHz / 5 kHz), with Tone Defeat
Filters: Low Filter (Subsonic 15 Hz / 30 Hz), High Filter (7 kHz / 14 kHz)
Inputs: Phono 1 (MM), Phono 2 (MM), Tuner, Aux 1, Aux 2, Tape 1 (RCA & DIN), Tape 2 (RCA)
Outputs: Tape Rec Out 1 & 2, Pre-Out, Main-In (separable preamp/power amp sections)
Speaker outputs: Screw terminals for 2 speaker pairs (Main, Remote, Main+Remote)
Front-panel connections: 6.3 mm headphone jack
Power supply: Switchable 110–240 V AC, 50/60 Hz
Power consumption: 330 watts maximum
Dimensions (W x H x D): 41.0 x 14.0 x 34.0 cm
Weight: 10.2 kg
Manufacturer: Matsushita Electric Industrial Co., Ltd. (Osaka, Japan)