I was promising an update on the Duelund Tinned Copper. Just before Christmas my wife's mother passed away and then my father just after so my brain was distracted.
Then a pop developed in the 500c when turning on.
So I put the EL84 back in and then heavy distortion in left channel.
Yes frustration was a little high!
On the way back to my dad's celebration of life we brought both amps in to Parts Connexion to find out what was wrong?
The EL84 had a failed Duelund VSF coupling cap. This took out two left channel tubes.
The 500c was suffering from low voltage and whole new power supply was installed.
CE Manufacturing and Mundorf are the power supply caps.
The old worn out power supply caps were acting like a resistor. I would have replaced years ago but there really was nothing.
CE has bought vintage Mallory components and is making caps again.
So my Fisher 500c is not stuffed cans but really a replacement of original power supply.
I know some would say again all new power supply caps better. One of the tests years ago was to see if a Jensen power supply cap was better than vintage. After a month or so the Jensen come out and vintage back in. Jensen sounded dry. I have no idea why but was glad when vintage went back in.