Re: Amp Volume Swell Problems
Posted: Thu Aug 30, 2012 2:36 pm
Also, video/audio of the problem so you're not having him chase a phantom or question your sanity. Should also cut down on bench time.
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Re: Amp Volume Swell Problems
Posted: Thu Aug 30, 2012 8:15 pm
Open up the amp, tap the tubes with the eraser end of a pencil while it's running. You should be able to tell if one of them is bad pretty easily, it'll ping or crackle. You'd think that would have been the first thing the tech would have checked though.
Re: Amp Volume Swell Problems
Posted: Tue Sep 18, 2012 6:15 pm
Friends,
I got my amp back from the second tech who also couldn't find anything wrong with it. That is, he played it, and could not duplicate the problem.
However, I think I may have solved it myself... we'll see in a few hours when I go to practice. But I just jammed on it for an hour and had no problems with it at all. And I think it's because of this:
There are three preamp tubes, and two of them have the little black plastic holder thing. The third one does not. It's not totally loose, but it moves around a lot easier than the other two when you jostle it with your finger. So I took it out and popped it back in. That's all. My amp hasn't been moved or picked up or anything... and, at least in my apartment, it seems to be working fine. I can't play it too loud here, but still, there were no swells.
It makes sense for other times that it's done the swelling... it gets brought to a tech, he checks all the tubes and stuff, and then plays it. No swelling. It's brought to a practice space (meaning it goes down some stairs, into my car, up some stairs, down some more stairs, and then set down on a stand), and is up and down enough during the trip to have perhaps loosened the preamp tube... and without me making sure it's tight up in there, perhaps it's not doing what it should.
Does anyone know what the hell these plastic ring things are called and where I can get one? It would be silly if this is the problem, but also fine with me, as that's a simple fix. Too bad I brought it to too different guys who may not have seen the problem.
Again, we'll see tonight after I transport that amp and make sure the tube is all the way in and not swayed left or right or whatever.
C
I got my amp back from the second tech who also couldn't find anything wrong with it. That is, he played it, and could not duplicate the problem.
However, I think I may have solved it myself... we'll see in a few hours when I go to practice. But I just jammed on it for an hour and had no problems with it at all. And I think it's because of this:
There are three preamp tubes, and two of them have the little black plastic holder thing. The third one does not. It's not totally loose, but it moves around a lot easier than the other two when you jostle it with your finger. So I took it out and popped it back in. That's all. My amp hasn't been moved or picked up or anything... and, at least in my apartment, it seems to be working fine. I can't play it too loud here, but still, there were no swells.
It makes sense for other times that it's done the swelling... it gets brought to a tech, he checks all the tubes and stuff, and then plays it. No swelling. It's brought to a practice space (meaning it goes down some stairs, into my car, up some stairs, down some more stairs, and then set down on a stand), and is up and down enough during the trip to have perhaps loosened the preamp tube... and without me making sure it's tight up in there, perhaps it's not doing what it should.
Does anyone know what the hell these plastic ring things are called and where I can get one? It would be silly if this is the problem, but also fine with me, as that's a simple fix. Too bad I brought it to too different guys who may not have seen the problem.
Again, we'll see tonight after I transport that amp and make sure the tube is all the way in and not swayed left or right or whatever.
C
Re: Amp Volume Swell Problems
Posted: Tue Sep 18, 2012 7:06 pm
They are called grommets and I'm not sure where to find 'em yet... Ask one of the Techs if they have any layin around...
Also if the base is right these might fit...
My '65 Kalamazoo has a loose tube and will do that and if I reach back there and push it in it stops...
Also if the base is right these might fit...
My '65 Kalamazoo has a loose tube and will do that and if I reach back there and push it in it stops...
Re: Amp Volume Swell Problems
Posted: Tue Sep 18, 2012 7:37 pm
You should be able to find them at yor local hardware store, I'd grab some vinyl ones or some high temp resistant rubber ones. Those are a little different from my AC30, you might take one of those out to bring to the store and find one that matches.