TAB/Maihak V73 tube amp noise. Change oil caps next?

[starseed]

Hi.

I'm learning about servicing tube amps and have changed the elytic caps in the V73's we use as headphone amps. They worked very well for a little while, but now one side developed a typical fizz/crackle that tells me it is time to swap something else.

Nearly all the elytic caps were changed, all except for the very long one with 4 connectors. I changed the value of one of them, no. 43 with advice from Werner who makes the Fairman equipment, increasing it to 47 uF. The one next to it in the schematic (no. 42) was changed with original value.

There are what looks to me like several paper in oil caps in a few places that I'm wondering if I should have a look at next.

Any thoughts on who the likely culprit is here?

I'll try to attach both a detail of the section with no. 42 & 43 in it, as well as the entire blow-up of the schematic (PDF).

Thanks,

Jeremy