General:

The Panasonic SA-420 is a receiver made by Matsushita National Panasonic audio HiFi division in Japan around 1965.

 

Front panel ^

 

^ frontpanel light.

 

Special futures:

This receiver is very well designed and well constructed and meets the most modern electronic design practises at the time.
Panasonic used the best available parts at the time and this is why this receiver still works fine in 2012.
It is one of the nicest receivers Panasonic has built in this time frame.

 

User Manual:

Click here to download the brochure PDF format

 

Schematic:

Click here to download the service manual in German language in PDF format (4Mb)

This solid state reciever uses all silicon transistors. The electronic design is very modern in its time.

The output amplifier employs NEC NPN silicon power transistors and a OTL and OCL output stage,
its power supply is symmetric running on +/- 15 Volts.

The tuner section is using a FET pre-amp and the the IF uses 4 IF transformers and a ratio-detector for FM.
The stereo decoder is traditional and of acceptable quality.

 

Inside the receiver.

 

Modifications:

The power supply is not to modern standards anymore, you can update it with 2x 4700 uF caps or better.
The sound and the power capability will improve.
With a little redesign of the power supply you can improve the current capability of the power supply you
will get a 2x12 Watts RMS amp at 8 Ohms.
Also some realignment of the tuner section will do good, the reception will meet modern standards,
with quite moderate noise figures and acceptable sensitivity.

Set the power transformer voltage setting from 220 V to 240 V in Europe.

Updating this receiver is very rewarding.

 

The power ampifier and power supply, as you can see best parts are used and its very well constructed.

 

Sound:

The sound is exceptional for this age receiver.

 

The legendary NEC 2SD254 Power transistors are of exceptional quality.