No sound on R channel after speedball

[Warmaster Horus]

Hello,

I just built my crack, and the standard kit went fine and worked great.
I added a neutrik locking jack, and alps pot, otherwise everything is "stock" from the crack kit.

Adding the speedball today, and after i finished adding speedball, there is no sound on RIGHT side.

I tried swapping input RCA cables, no change.  Tried a few different headphones, no change.

Here are my voltages from the speedball build:
Small Board:
OA: 82.7V
IA: 177.4V
B-A/B: 0V
IB: 177.4V
OB: 75.7V

Large Board:
OA: 109V
OB: 108V
G: 0V
B+: 177.4V

OA and OB on the small board are fairly different, but within the "OK" range..
Solder joints all look good..

Only other thing that stands out to me is the large board resistance check: Both OA and OB are showing no connection (my DMM has range up to 20MOhm, and reads "OL - overload" on OA and OB).

any help and troubleshooting tips would be greatly appreciated.

Thanks!

[Warmaster Horus]

Hi all,

I gave my eyes a break for a bit, and rechecked connections.
Found the R channel connection to the jack came loose at the terminal strip.
Resoldered, and all is good, output from both channels.

But should i be at all concerned about the difference in voltage on the small board at OA and OB?

Thanks!

[Doc B.]

That much difference is not a big deal.

[Warmaster Horus]

Hi Doc,

Thanks for the reply!

Just for my education/curiosity, could you give me any insight as to what could cause the difference?
(slight inbalance in halves of the tube, etc?)

Thanks!

[Paul Joppa]

You got it - it's variations in the two sections of the tube itself. Even the mil-spec versions are about +/-25%. This is of little significance, at least to my ear. The least expensive experiment is to get another tube of the same manufacturer and production date; it will have a different imbalance but should have the same sonic signature, so you can see whether you can hear any difference.

For a lot more cost, you can seek out tested tubes with better balance between sections. But they are rarely matched at the operating point you are interested in, so finding one that's well-matched in service means buying a bunch and trying them out. They won't remain matched as the cathode wears out, though. Not worth it to me, unless you just want to hear if there is a difference - i.e. an educational experiment.