The tubes won't seem to hold a steady bias, so I wonder if I cooked them. I'm taking them to be tested at a local shop, but in the meantime I start scrutinizing the other aforementioned "curiosities" (See picture links below).
1) An extra transformer is mounted at the right rear which is being used to supply power to the PCB instead of using the main input transformer. Huh? Anyone ever seen this? Should I remove this and revert to the wiring scheme recommended by VTA?
2) There are no ground wire connections from the PCB to the RCA inputs. Curious how big a problem this may be?
3) Note the wiring of the 10 ohm resistors between pins 1 and 8 of both output tubes, with a ground wire from between the resistors to the ground on the PCB. This doesn't seem quite right - this circuit adds 20 ohms of resistance between the 2 tubes.
4) The white wiring that was used to wire the pentode / triode switches is stiff solid-core wiring. Not sure of the gauge, I think that 20-22 gauge stranded teflon-coated wire is recommended. This is definitely heavier than 20 gauge Should I replace this?
I've tested all resistors in both channels and all test fine. This week I'll be running further tests but would love to have ideas from others on this great forum.
thanks in advance ...
pictures (inlcluding photobucket links as well as embedding them here)
Original quad-cap wiring:
Left channel close-up: