73 Silver face Twin Reverb ?

[überfuzz]

About the hum... How bad is it? Old point to point wired amplifier often have some glitches, a little hum here and and some occasional pops there. You're sure the hum isn't in the realms of ok?

Is it a balance bias or level bias. (I don't know the English terms.) Did the re-bias effect the buzz to?

[gtrplayr1976]

The HUM isn't so bad . It's the buzz that was/is the main problem. Guess I started this thread with the wrong idea ... I added a bias trim pot for the tube bias. It has the balance pot also.

[überfuzz]

Guess I started this thread with the wrong idea

Ah well, haven't we all, occasionally.

I still like to see if the buzz is effected by replacing the power tubes. See if you can try a balanced quad just to make sure it's no tube issue.

[gtrplayr1976]

The quad I put in was matched, and new . I may have another 6L6 I can use to swap for test purposes.

[überfuzz]

The quad I put in was matched, and new . I may have another 6L6 I can use to swap for test purposes.

Well, all vendors aren't as cagey as we are...

[gtrplayr1976]

Actually just plugged it up to another speaker ,and it sounds pretty good. I think I'll order new caps for the rest of it. There is no hum at all ...still not sure about the buzz, but I don't hear anything but the fret buzz if I hit it too hard. I'll see how it sounds with the original speakers.

I have the master at 5, and the volume at 3....doesn't sound that loud to me , but I'm only using 1x12 cab, and I'm a little hard of hearing.

[gtrplayr1976]

So I've ordered the remainder of caps to replace in this amp. May as well do it now while I have it apart. I think it may work well now...we'll see. Stay tuned

[gtrplayr1976]

OK...I have replaced all but one cap in this amp. I have powered it up ,and played through it. The main thing I noticed this time was an oscillating buzz , but it seems to be dependent on the amp position, so could this be ruled out as an outside interference ? Other than this ,it seems to work well .

[überfuzz]

Wasn't the noise coming from the cabinet..?

I don't know... Do you have gut shots? This might be a long shot, but worth trying.

Sometimes noises can be induced by a simple thing like a wire bad placed. Ins and outs away from each other. Wires close to chassis, ground shield. Do you have any idea of where the oscillating buzz comes from. Try pulling and poking the wires there.

[gtrplayr1976]

Well...I have absolutely NO noise with no input. I can crank the volume ,and all up and very little of anything. I think the buzz may be an interference of some kind when I hook up the guitar. I may try another guitar just to rule that out. It originally was a low frequency buzz only when I plucked the low E, or A. I went through ,and checked solder joints since I replaced about all of the caps. I do have some gut shots I'll post for you. I have more somewhere on here.

[überfuzz]

Try a guitar with humbuckers, try different locations and angles with the guitar.

[gtrplayr1976]

That's what I want to do. The guitar I used was a Firebird copy ,and I did notice how I angled the amp made a difference. That's why I thought it may just be something other than the amp.
Did you ever find the issue with the Twin you were working with ?

[überfuzz]

I sure like to think so... Right now my bets are on the cathode capacitors. I'm going to lift one leg at the time to rule them out, or nail the issue. Haven't got the time though.