Belcat 20R Service

I had a Belcat Tube amp in my workshop.  this was distorting  but not in a nice way.  It really made your ears hurt!
This is  a Fender Blues junior copy.  The rectifier is solid state and there are three ECC83’s and the output is two EL84’s. I tested the valves on my tester just to make sure they were OK and they were perfect.
I again replaced the output protection diodes with R3000 from Diodes Inc as again I thoughy using in 1N400x diodes were not the going to provide long term protection.  I put a signal generator on the input and the sine wave from the signal was faithfully amplified right up to the inputs of the EL84’s. However the output was a horrible looking waveform.
I then took the amp fully out of the cabinet to have a look at the output transformer.  I was in for a surprise. A mains transformer was being used as an output transformer. See the picture of the removed transformer and the label on the top.  I do not  have the specification of this transformer but, it is clear it was never designed for this application. If it had the right frequency response , then this was by luck.
I therefore replaced this transformer with one designed as a replacement for Fender Blues Jr amps.  The result was a really sweet sounding am that sounded like a Fender Deluxe amp with Vox AC15 blended in.  I honestly cannot believe this am ever sounded any good. However it now is ready for a long life producing a real nice sound.
So if you if have a Belcat Tube-20R, I would recommend ( IF YOU ARE SUITABLY QUALIFIED)  then get the amp out of the case and check out the output transformer and if it is like the one below.   ( dont forget to fit R3000 diodes) Replace the output transformer  and you will “transform” the sound of this amp !!