left channel suddenly out of balance [resolved]

[Paul Birkeland]

With one probe on each of the 6.3V terminals, what DC voltage do you see?  It occurs to me that it's possible that your 6.3V regulated DC supply may not be putting out sufficient voltage for proper tube emission, so that's worth looking into (or there's something in the heater circuit consuming extra current).

[kill_surf_city]

With one probe on each of the 6.3V terminals, what DC voltage do you see?  It occurs to me that it's possible that your 6.3V regulated DC supply may not be putting out sufficient voltage for proper tube emission, so that's worth looking into (or there's something in the heater circuit consuming extra current).

Okay, I'm getting 6.25v on the 6.3 V terminals on the PSU board.

[kill_surf_city]

With one probe on each of the 6.3V terminals, what DC voltage do you see?  It occurs to me that it's possible that your 6.3V regulated DC supply may not be putting out sufficient voltage for proper tube emission, so that's worth looking into (or there's something in the heater circuit consuming extra current).

Hey PB, I noticed that one of the screws that is supposed to secure the PSU board just wasn't there, found it and screwed it in. I decided to go ahead and connect everything and redo my voltage tests. Everything was well within range on all boards. The Kreg on the shunt regulator is still showing me ~1.9v  on both sides but I went ahead and turned it on and everything sounds perfect to me. No balance issue. No hum. Do I still need to worry about that Kreg value on the shunt regulator?

[Paul Birkeland]

If the front C4S board is hooked up and you still see 1.9V at each of the Kreg pads on the board above the D socket, what's the DC voltage at the +275V pad on the power supply board above the power transformer?

[kill_surf_city]

If the front C4S board is hooked up and you still see 1.9V at each of the Kreg pads on the board above the D socket, what's the DC voltage at the +275V pad on the power supply board above the power transformer?

With the C4S board connected I'm getting 5.94v on side A and 5.92v on side b. DC voltage on the +275 pad is 265v.

[kill_surf_city]

I do also have the step up transformers installed if that makes any difference.

[Paul Birkeland]

Those Kreg voltages are more reasonable and should be sufficient for the circuit to operate properly. 

[kill_surf_city]

Those Kreg voltages are more reasonable and should be sufficient for the circuit to operate properly.

Awesome. Thanks for you help Paul.