Strange volume problem with a Twin....

[Andrew Lamprecht]

I got this Twin recently and I like it a lot. I sprayed contact cleaner in it as many knobs were scratchy. All the scratchiness went away except for the volume. It improved a little but still noticeably bad. The thing that I am asking about is this... no matter which way you control the volume it is really scratchy. ie If I have a guitar and control the volume with the guitar it makes the same scratchy sounds as if I did it with the knob on the amp. It has happened with each guitar I have tried AND the volume spikes hit at the same points no matter which guitar or on the amp. Like a peak will happen at 3 on the amp and if I am at 4 and turn the guitar down to about 8.5 it hits the same peak each time I hit that point on the knob. Really strange eh? Any ideas?

 

[Empty Pockets]

Re: Strange volume problem with a Twin....

Broken

Throw that Green Rhino in the back of it and send it to me for proper disposal.

 

[zzmoore]

Re: Strange volume problem with a Twin....

I have had a tube react that way.
I would have SWORN it was a "bad" spot on the pot surface, but a new volume pot did the same thing.
Changed the preamp tube and all was well. There were no other signs of the tube being bad. No microphonics, popping, etc etc.
good luck

 

[Agileguy_101]

Re: Strange volume problem with a Twin....

I have had a tube react that way.
I would have SWORN it was a "bad" spot on the pot surface, but a new volume pot did the same thing.
Changed the preamp tube and all was well. There were no other signs of the tube being bad. No microphonics, popping, etc etc.
good luck

I was there when he was experiencing this problem (it was my amp) and I remember there was a scratching when I turned my guitar's volume. Check the tubes.

 

[Chickenwings]

Re: Strange volume problem with a Twin....

cant hurt to go thru all the toobs first. Especially the 12at7 in the PI spot.

 

[Gearjoneser]

Re: Strange volume problem with a Twin....

Broken

Throw that Green Rhino in the back of it and send it to me for proper disposal.

Funny you mentioned the Green Rhino, because I've spent this past week with my vintage Fender Pro Reverb, seeing which OD works the best with it, and out of my pedals the Green Rhino won.

The Green Rhino is one of those rare OD pedals that works really good with clean amps, where most of them excel with midgain tones.

 

[Gearjoneser]

Re: Strange volume problem with a Twin....

As for the problem of noise on the top and bottom of the pot, no matter which pot is controlling volume, I have a feeling there's some sort of ground loop or bad electricity where it's all plugged into.

I say that because I don't know the exact answer, but I experience it sometimes in places where I have a feeling the ground isn't properly grounded to the earth.

 

[zzmoore]

Re: Strange volume problem with a Twin....

I was there when he was experiencing this problem (it was my amp) and I remember there was a scratching when I turned my guitar's volume. Check the tubes.

THAT was a strange day. Kind of felt stupid..... "What is the first thing you check on a tube amp when there is a problem.?"
But this was frequency dependent. It happened every time at a bout 4 on the volume knob. So I just ASSUMED it was a bad spot on the wiper surface. Then I thought perhaps it was a cap leaking DC in a weird way, so I changed the Mica Cap involved. Neither of those did the trick. I thought No Way is it the tube.....
Thanks for the "fun" build
Chip

 

[Empty Pockets]

Re: Strange volume problem with a Twin....

Funny you mentioned the Green Rhino, because I've spent this past week with my vintage Fender Pro Reverb, seeing which OD works the best with it, and out of my pedals the Green Rhino won.

The Green Rhino is one of those rare OD pedals that works really good with clean amps, where most of them excel with midgain tones.

Ahem... no... it is a broken pedal and he has a broken amp and he needs to send them to me so i can dispose of them properly.

 

[cream123]

Re: Strange volume problem with a Twin....

it could also be a burnt out/non functional component. When I was doing a pedal build once, I had a similar issue and it had to do with too low of an impedance on the input stage due to broken cap. Check the tubes first though, always start simple with debugging.

 

[misterwhizzy]

Re: Strange volume problem with a Twin....

it could also be a burnt out/non functional component. When I was doing a pedal build once, I had a similar issue and it had to do with too low of an impedance on the input stage due to broken cap. Check the tubes first though, always start simple with debugging.

I get the feeling you're not reading Empty_Pockets' posts.

 

[cream123]

Re: Strange volume problem with a Twin....

I get the feeling you're not reading Empty_Pockets' posts.

Just because I'm not responding to them doesn't mean I'm not reading them.

 

[Empty Pockets]

Re: Strange volume problem with a Twin....

I think cream is still mad at me because of all the bad advice I gave him when he was a teenager :smokin: