Note: this is one of the older articles from my archive, dating back to a time when the SB-LAB workshop was still growing. The photos are not perfect, but they capture the artisanal spirit and the passion I have always put into every restoration. The protagonist this time is a classic Fisher 500C, one of the most iconic tube receiver amplifiers from the golden age of American hi-fi.

This Fisher 500C receiver amplifier was delivered to me in original condition, with only a few age-related issues. The chassis was greasy, and the sockets, selectors, switches, and potentiometers needed a thorough cleaning. I tested all the tubes for safety: they were all good, except for one EC900 installed in place of an EC97, and the four output tubes which, although working, already showed signs of darkening and getter evaporation.

The work consisted of a complete cleaning of the chassis and controls, replacing the wrong tube with the correct PC97, and installing a new quartet of output tubes. After the intervention, the unit went back to operating stably and quietly.

At the end of the overhaul I measured some audio characteristics of the unit, just out of curiosity. The results confirmed what I often repeat: not everything that is vintage or prestigious is automatically hi-fi. The numbers are clear.

Measured results:
Bandwidth at 1 Watt: 25 Hz – 13 kHz (-3 dB)
Bandwidth at 20 Watt: 23 Hz – 11 kHz (-3 dB)

Despite its technical limits, the Fisher 500C remains a fascinating piece, a witness to an era when hi-fi began to enter homes with elegance and tube warmth.
If you own a Fisher, a McIntosh, or any other vintage amplifier that needs restoration, you can contact me through the “Services” section. I will evaluate the most suitable intervention to bring it back to its best operating and sonic condition.