Seymour Duncan eating rectifier tubes

[Dave Curtis, dB AudioTech]

You may indeed be very correct,
I had found that when using a brand new Sylvania 5U4 the arc issue would go away, For A While, Then after a good number of hours, It would happen more and more often until I replaced the tube.

BTW, that arcing is brutal on power and output transformers, I ruined a brand new bandmaster power trans like that.

I have seen that exact symptom in a couple of amps I built that had way to much capacitance combined with a low decoupling resistor it was a huge issue. I fried several 5Y3's trying to run 47uf,r100,47uf,r100 47uf. That is not even close to how high the Duncan is.

In all honesty, that much capacitance is not required for fairly good filtering and it makes no sense that they had it that high.
This might be just what mine needs.
Trout

RCA says 40uF:
http://www.pmillett.com/tubedata/HB-...t_1/5U4-GB.PDF

I had one come in that someone had put 320uF/450v caps in. I put a pair of 80uF in and it was happy.

The build is troublesome, IMO. Those little pin & sleeve connections... Be careful with the module sockets; I wasn't able to find a replacement, so I had to resort to the bonepile to fix broken contacts on one.