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Sansui TU-777 tuner


 

General:

Beautiful tuner with excellent performance, made by Sansui in 1968.

 

 

 

Specifications:

Sansui TU-777

Type: Mono/Stereo Tuner

Tuning Bands: FM, MW

Tuning Scale: Analogue Round

FM Tuning Range: 88 to 108 MHz

MW Tuning Range: 535 to 1605 kHz

Sensitivity: 1.4uV (FM) mono, 14uV (MW)

Signal to Noise Ratio: 70dB (FM)mono

FM stereo channel separation: >35 dB

Distortion: 0.6% (FM)stereo

Selectivity: 55dB (FM), 30dB (MW)

Output: 2000mV max.

Semiconductors:

Transistors: 28
Fets: 1
Diodes: 24

Dimensions: 345 x 155 x 334 mm

Weight: 7.4 kg

Price: 37,800 yen (3/1968)

Year: 1968

 

Special futures:

FM/AM round scale with tuning meter and stereo lamp.

 

 

 

User Manual:

Click here to download the TU-777 usermanual in PDF format.

You should set the FM - MPX separation setting and output control at the back panel correctly.

 

 

Power supply main caps ^

 

Power supply secondary caps ^

 

Schematic:

Click here to download the TU-777 schematic in PDF format.

Click here to download the TU-777 schematic in JPG format.

There are transistors only and one FET involved and a lot of diodes: no IC's.

The AM section is more than a average 6 transistor radio made in Japan.

 

 

internal bottom Sansui TU-777 ^

 

Modifications:

The build quality is excellent, although some parts are less easy accessable. The S-meter is of good quality.
I checked and all electrolytic caps are out of specs.
Also some wiring is awkward, that many Sansui gear have from that time frame.

You may exchange all electrolytic capacitors that are out of specs.
My TU-777 stereo-decoder had not the 0.22µF capacitors, but the 3-lead filter-hybrids FP-38A as seen on the picture below.
The FP-38A is the European 50 µS version of the original FP-38 that is 75µS.

In some TU-777 the de-emphasis setting is not set correctly: in Europe it must be 50µS and in USA 75µS.
You may change this by changing the value of C or the FP-38 filter version.
Below some explanation in French.

https://www.sonelec-musique.com/electronique_bases_diffusion_fm_preac_desac.html

Set the power transformer to 240V line voltage when you are in Europe, the used power transformer
will get hot: as its not designed for Europe's todays
detrimental 230+ Voltage in the standard selected 220V position.

 

Stereo decoder FP-38A parts ^

 

AM section version 1 ^

 

Audio Section ^

 

4 gang FM capacitor front-end ^

FM front-end bottom ^

 

Stereo decoder ^

 

IF sections ^

Back ^

 

Sound:

The FM reception and sound of this tuner is excellent, really unprecedented after restoration, regarding the more than 50 years of age:
many much more complicated modern FM tuners cannot reach this kind of quality. A unique high-end product of its time.

 

 

 

 

 

 

 

 

 

 

 

 

 

Front ^

 

Woodcase ^

 

Complete Sansui 1968 series ^

 

 

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© PE1MMK Hans Hilberink last update: 10-10-2020.