Fender '65 Deluxe Reverb: weird breakup fault fixed

[Dunnie]

My '65 Deluxe Reverb was breaking up so badly at quite low levels that it was not usable. I checked out all of the usual stuff, connections, tubes swapped out including the rectifier, filter caps bridged with good ones etc. As I am a techie, I then went under the chassis and checked all the signal levels, voltages and so on without any luck. I then hooked up an oscilloscope to the HT rails and sat playing guitar. I could then see that the HT became unstable under load. The problem was that all the axial electrolytic filter capacitors under the cover on top of the chassis had lost some but not all capacitance. Maybe a bad batch. I replaced the 47MFD and the three 22MFDs and the amp is back to normal. As this was a bit unusual I thought that I would post this in case any other guys come up against this. If there are some bad caps out there, there will undoubtedly be other failures along the same lines. Best of luck everyone.

[Stevem]

When I recap and or build a amp I form all of them over the course of 6 hours starting off at 40 volts in a rig that I made up and then I test them for ESR and UF value.

In terms of Uf valve you it can make a big difference, and yes some new caps from every brand that I have used fail to make the grade!

It also brings up the question of why some folks do not hear the out of tune and loss of punch when playing there vintage amps loud that only have a combined total of some 35 uf on the first filter node?

Assuming that the rectifier tube test out at 80% or better on both halves Then these amps also seem to sound there best with any 6V6 that also test out high / good if they are biased in at no more then 18 ma each if you care to play around with that.