Might have wiggled something loose... right channel static [resolved]

[Colonl_Charisma]

100% certain that I measured A3 and A8 of the 9-pin socket.

The center post of the 9-pin socket measures = 171V.

What might be causing the issue? Could it be the mods?

[Paul Birkeland]

The center post of your 9 pin tube is not at ground.

You have a ground wire that's loose or not well connected.  Remember that the center pin of the 9 pin socket wires to terminal 3, which touches the chassis.  You cannot simultaneously have that connection present and have 170V DC there.  So yes, it's a loose, broken, or unsoldered ground wire.

[Colonl_Charisma]

Awesome! Thanks for helping me diagnose the issue, PB. I'll do some investigation on my end, and I'll report back.

[Colonl_Charisma]

I may have a rather embarrassing admittance to a mod I made a couple years. If you remember, I added a balance potentiometer to my BH Crack.

Well, upon investigating my circuit tonight, it appears I severed the ground connection that links the 9-pin socket to terminal 3. If you look at my PEC pot photos, you'll notice that I no longer have a connection between the upper and lower lugs closest to the 9-pin socket. I DID have this connection in the past. If this is the case, it is 100% my fault, and this would explain the voltages being seriously off.

Photos are of my PEC pot.

[Colonl_Charisma]

MAJOR UPDATE:

I did some re-wiring to link my ground connections at my volume pot, and I can confirm all LEDs are brightly lit. My voltages are also normal.

OA = 106 V
OB = 109 V
G = 0 V
B+ = 194.5 V
Middle 9-socket pin = 0 V

PB, let me know if you'd like for me to check anything else before I flip it over! Thank you for your help!

[Paul Birkeland]

It seems like you tracked the issue down.

-PB

[Colonl_Charisma]

Thanks for all your help, PB!

I can confirm that all my issues went away after correcting the grounding issue. No more right channel buzz, voltages normal, and all LEDs are brightly lit. It's crazy how much "noise" I had coming through my headphones, because now I cannot tell if the amp is on or off with my headphones on my head.

This is a textbook example of always checking voltages after any work on the amp lol. You can mark this issue "resolved".