Sansui 300L receiver

General: 

This receiver was first produced by Sansui company Japan in 1968, it has great reception capabilities and sound is excellent.

 

 

Photos:

Front of the Sansui 300 without L, no long & short wave ^

 

Interior view FM stereo-decoder ^

 

With different knobs ^

 

The SW fine-tune knob ^

 

300L interior ^

 

Specifications:

Tuning range: FM, LW, SW, MW, standard broadcasting bands

Usable FM stereo sensivity 4 µV mono, 15 µV stereo

Power output: minimum 15 Watts RMS per channel into 8 Ohms (stereo)

Frequency response: 15 Hz to 35 kHz

Total Harmonic Distortion: 0.1%

Damping factor: 25

Max output power: 25 Watts IHF (DIN) per channel

Input sensitivity: 3mV (MM), 180mV (DIN), 180mV (line)

Signal to noise ratio: 65dB (MM), 80dB (line)

Channel separation: 45 dB (MM), 50 dB (line)

Output: 180mV (line), 30mV (DIN)

Speaker load impedance: 4 to 16 Ohms, 8 Ohm recommended.

Semiconductors: 36 x transistors, 1 x FET, 2 x varistors, 1 x thermistor, 18 x diodes, 1 x zener diode

Dimensions: ~ 15 x 4 x 11 inches

Weight: 21 pounds

Year: 1968/69

 

electrolytic caps exchanged ^

 

 

Special futures:

This Sansui 300L tuner-section has FM & AM with LW, MW, SW. A fine tune knob,
with built-in antenna, and extern antenna connectors. Reception is excellent.
In 1968 it was a quite expensive receiver: $HK 900.-.

 

Back panel ^

 

SW module ^

 

Schematic:

The Sansui 300L service manual in pdf format, download click here

The Sansui 300L schematic diagram in pdf format, download click here

 

Power-amp pcb unrestored ^

 

Power-amp pcb restored ^

 

Modifications:

The lamps can be exchanged by leds.

All electrolytic capacitors must be replaced. Some values of capacitors can be changed to the power supply rail,
to improve stability.

Exchange the 1000µF power main caps for 4700µF and exchange rectifier diodes too for 10A general purpose diodes,
for optimal sound and 2x 20 Watts output capability.

You may change the electronic design and connect the FM stereo outputs directly to the tone-amp input via the input switch.
To get correct sound levels with the other inputs you may add 2 capacitors of 10 to 47 µF in the tone amp.
This improves sound quality and noise levels.

If you have broken final power transistors, the 2SC830 can be replaced with 2N3054, that works great.

 

Power-amp pcb layout ^

 

FM IF pcb ^

 

Speaker connectors ^
 

Power transistor Hitachi 2SC830 ^

 

This is how nice the dial pointer can glow with a led ^

 

Sound:

Excellent sound.

 

These Sansui audio components soon got legendary by their outstanding build quality and good sound.

 

© Hans Hilberink - PE1MMK ® 2000 - Last update: 15-09-2021.