Fisher X-100-A amp #64732E

[Karel Mars]

Hi All tube amp lovers

I have this interesting stereo hif amp on the bench. Problems were low power on one channel. The owner had to turn the balance all the way to the right hand side to get 'n reasonable output from both channels.

I took some phots while I opened it.

 

[Family_Dog]

Balance problem sorted now Karel? Looks like it has been recapped.

-F_D

 

[Karel Mars]

Balance problem seems to have been caused by two problems. A failed output tube and oxidation on one of the ECC83 tubes.

Replacing the 6P14P's with 6P14P-K's I got from Ari solved the output stage misbalance. As a matter of fackt they dropped in without having to change bias setting at all. The tubes are running at a full 14 watt (just a notch below) though. Should be good for 3000 hours or so?






Swopping the two ECC83's the were mismatched made the imbalance go away. I suspect oxidation on the tupe pins. I cleaned the tube pins and all seems well.

This amp has got a lot of bass. I had to turn the bass down fully to get a more or less flat response.