Restored Sansui AU-7700 Integrated Amplifier

Restored Sansui AU-7700 Integrated Amplifier

49 Capacitors Replaced.

28 signal transistors replaced.

Power supply capacitors 10,000uf 50 volt (qty. 2) were upgraded to 12,000uf 63 volts.

(Qty. 1) 10 ohm 2 watt resistor replaced.

Entire unit cleaned inside and out including faceplate.

All switches and potentiometers cleaned and lubricated.

Regulators removed and new thermal compound re-applied.

Bias and zero volts adjusted to specifications.

Tested over 40 hours with no issues.

Restored December 2024

*** Please note that the Low Filter Frequency switch no longer has the indent (locking feature) positions but still works. This switch slides and works fine but the indent feature is most likely worn out after many years of use. The rear of the unit and top cover have some rust and wear consistent with its age (see photos). I don't believe the "speaker selector", "Tape Play", or "selector" knobs are original but these came with the unit****

When I obtained this amplifier it had no output, only static and a fizzling sound. Most of the original signal transistors had become "noisy" in the pre-amp and amplifier sections and were replaced. Most of these transistors will become noisy or intermittent in the future if not replaced. Also I noted a discolored 10 ohm 2 watt resistor that measured only 6 ohms and was replaced as well.

**** No meet ups or P.O. Boxes****

Specifications:

Power output: 54 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 50kHz

Total harmonic distortion: 0.1%

Damping factor: 30

Input sensitivity: 2.5mV (MM), 100mV (DIN), 100mV (line)

Signal to noise ratio: 75dB (MM), 85dB (DIN), 85dB (line)

Channel separation: 75dB (MM), 85dB (line)

Output: 100mV (line), 30mV (DIN), 0.8V (Pre out)

Speaker load impedance: 8Ω (minimum)

Semiconductors: 57 x transistors, 22 x diodes, 3 x zener diodes, 1 x LED

Dimensions: 434 x 130 x 315mm

Weight: 12.3kg

Year: 1975