Sansui TU-777 (1968)
Top-of-the-line solid-state FM/AM tuner released in March 1968 with advanced FET front-end and electronic stereo switching.
Overview
The Sansui TU-777 is a high-end FM/AM tuner introduced in March 1968 as part of Sansui's premium lineup. It's solid-state, with 28 transistors, 1 FET and 24 diodes - no integrated circuits. It was engineered for exceptional FM reception and stereo decoding. Sansui marketed it as a top-of-the-line tuner. The superheterodyne circuit uses IF frequencies of 455 kHz (AM) and 10.7 MHz (FM), with a 5-stage IF amplifier and a 4-stage limiter built around silicon transistors. The front-end is 4-gang FM and 3-gang AM, and the circuit boards are laid out independently to improve signal isolation.
Specifications
| Receiving frequency (FM) | 76 MHz to 90 MHz |
| Receiving frequency (AM) | 535 kHz to 1605 kHz |
| Sensitivity (FM, 20 dB quieting) | 1.4 μV ± 3 dB (300Ω balanced) |
| Signal-to-noise ratio (FM) | 65 dB (input 60 dB, 100% MOD) |
| Total harmonic distortion (FM) | 0.8% or less (input 60 dB, 100% MOD) |
| FM stereo separation | 35 dB or more |
| Rated output voltage | 2 V (0 ~ 2 V variable) |
| Load impedance | 100 kΩ or more |
| Power consumption | 10 W |
| Power supply voltage | 100 V, 50 Hz / 60 Hz |
| External dimensions | 345 mm (W) × 155 mm (H) × 334 mm (D) |
| Weight | 7.7 kg |
| Semiconductors used | Transistors: 28, FET: 1, Diodes: 24 |
Design
The first stage of the FM RF section is a junction-type FET. It's followed by a mixer and a silicon transistor oscillator with four variable capacitors. Zener diodes stabilize the IF and front-end power supplies, and the local oscillator has full temperature compensation. There's a 3-stage AGC system and a noise canceler that removes noise without attenuating high audio frequencies. The stereo decoder uses FP-38A (50 µS) or FP-38 (75 µS) filter-hybrids. The front panel has a green-glowing ring circular dial (BLUESS Laboratory), a signal strength meter and rotary flywheel tuning. A rotary selector handles FM/AM switching (AM, FM Mono, FM Auto, FM Stereo). Stereo/mono switching is purely electronic and responds automatically to the broadcast signal in FM-AUTO mode. The back panel has 300 Ω and 75 Ω antenna inputs, AM/FM antenna terminals, ground, RCA outputs, separation and output level adjustments, and an unswitched AC outlet. AM reception uses a built-in ferrite bar antenna. For FM there's a Local/Distant switch and a 20 dB attenuator.
Market
The TU-777 was listed for sale at €300 on February 11, 2026, via 2ememain (HifiShark). A unit was purchased for $75 in 2012. Common problems are degraded electrolytic capacitors and incorrect de-emphasis settings. European models need 50 µS (FP-38A), while US models use 75 µS (FP-38). Units used in Europe may need the power transformer adjusted because of higher line voltages.
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