I have recapped my O amp on my 1422.
The 5U4 tube has a lot of sparking inside the tube.
I have tried other 5U4's, and the same thing happens, even without the other tubes, and no input/output plugs (I jumped the ac on the speaker receptacle.)

I have tried double and triple checking, but I cannot find a problem.

Does anyone have any suggestions on where to look?

Thanks