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I am recapping my BF Champ and failed to notice it needs a 2uf cap (instead of the 25uf I ordered with the others) attaching to pin 8 of the 12ax7. I do have a 10uf, can I use it? Any ramifications, sonically, or elsewise?

Thanks.

It's just a bypass cap.

I'd just use the 25uf.

Shouldn't be a whole lot different than the 2uf sonically.

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Granville Guitars - Guitar & Amplifier Repairs - Custom Effects Pedals - Hand Wound Pickups
http://www.granvilleguitars.com/

Thank you, sir.

I did use the 25uf, and, I noticed, maybe, a bit more bass present? Could just be a properly functioning cap, too.

It will alter gain a bit. Might be that.

_________________
Granville Guitars - Guitar & Amplifier Repairs - Custom Effects Pedals - Hand Wound Pickups
http://www.granvilleguitars.com/

Hey Scooter,
I noticed the amp is humming when I turn it on. It may have been there before I recapped it, can't remember. Is there another cap(s) I should change out or might it be another component?

(BTW, I did change the can and the other 25uf (bypass?) caps.)

Thanks again!

Recheck your work.

After filter caps the most likely source of hum is tubes.

If none of that gives you joy, recheck your work again and doublecheck your lead dress.

_________________
Granville Guitars - Guitar & Amplifier Repairs - Custom Effects Pedals - Hand Wound Pickups
http://www.granvilleguitars.com/

Not the tubes (easiest place to start at this hour).

Will pop it open and check the insides....

Had a peek inside and I reflowed the solder on everything I changed and the hum still present. I am not real familiar with lead dress issues. From my limited knowledge it has to do with the wiring inside the chassis, correct? I did not move any wires while changing the components and today I did move most all of them (with a chopstick) and noticed no difference.

As a side note, my Princeton Reverb II that was serviced last year by my regular tech, has approx. the same amount of hum in it....

There are so many things to look at.

How many different tubes did you try?

With an older single ended design like this one there are tons of places for hum to creep in.

Try chopsticking the inside while it's powered up and see if you can influence the hum in any way.

It's possible that the two 68k input resistors may work better attached directly to the input jacks.

_________________
Granville Guitars - Guitar & Amplifier Repairs - Custom Effects Pedals - Hand Wound Pickups
http://www.granvilleguitars.com/

I have tried at least 2 sets of each tube (different brands, vintages, AY7, AT7, etc.) with not much variance. At the moment I have a JJ6V6S in and it seems to have the least amount of hum.

I did, in fact chopstick the wires while I had it open to redo the solder joints. Can't say I noticed much difference.

Thanks again, Scooter, for your input!