Preamp Tube Making High-Harmonic Noise

[FAN HALEN]

Hello,

I have a Friedman Marsha amp and I'm getting a high frequency harmonic sound when I hit a power chord. I believe it's the first preamp tube (from left to right) that's giving me the problem because when I flick it there's a high pitch noise coming through the speaker (all the others don't do this). I replaced the tube with several others (in fact I replaced all the preamp tubes) and I'm still getting this high harmonic noise.

Anyone have an idea what is causing this and is there anything you can suggest I try to get rid of it?

Thank you!

-Derek
http://www.fanhalen.net

 

[LP Freak]

Call Dave. He'll help you out.

 

[Shark Diver]

Sounds like a microphonic tube(s).

 

[Shark Diver]

Sounds like a microphonic tube(s).

 

[LP Freak]

I thought the same but he says he changed them.

 

[Shark Diver]

I thought the same but he says he changed them.

Yeah, I'm not sure. It be my luck I'd have 3 bad tubes,

 

[MrDan666]

Preamp tube quality is awful these days.. Sometimes I'll have to cherry pick them from large batches and VERY few of them are low noise/low microphonics.

 

[FAN HALEN]

It's not a continous harmonic ring. It only last for a few 10ths of a second after I hit a power chord...see video. Thank you!!!

 

[Shark Diver]

So the amp tech says, "does it chirp when you hit a power chord?" Patient replies, "yes, it does." Amp tech says, "don't hit power chords."

I'm not an expert on that stuff, but microphonics aren't continuous to my knowledge. So, I would still guess that. Or maybe some kind of clipping on the front end, but that doesn't make much sense to me. I'm sure some one will have a better take on this.

 

[MrDan666]

Call me crazy, but that noise sounds like it's being caused by your trem springs ringing... Or even could be ringing behind the nut. Put some foam underneath the springs and see if it solves the problem.

 

[LP Freak]

Call me crazy, but that noise sounds like it's being caused by your trem springs ringing... Or even could be ringing behind the nut. Put some foam underneath the springs and see if it solves the problem.

Good call Dan.

 

[Shark Diver]

Call me crazy, but that noise sounds like it's being caused by your trem springs ringing... Or even could be ringing behind the nut. Put some foam underneath the springs and see if it solves the problem.

Good call Dan.

+1

 

[Anonymous]

Call me crazy, but that noise sounds like it's being caused by your trem springs ringing... Or even could be ringing behind the nut. Put some foam underneath the springs and see if it solves the problem.

Good call Dan.

+1

99% sure it's a body noise on the guitar. now, the tricky part, if it's not the trem springs (my #1 suspicion in every noisy guitar), what is it.

sometimes chambered guitars do this too....if you can get in there and put some foam to deaden the noise, do it.

 

[MrDan666]

Many times it's also strings ringing behind the nut, and that's easy to fix. You can just take some foam and weave it inbetween your strings up by the headstock behind the nut

 

[Anonymous]

Many times it's also strings ringing behind the nut, and that's easy to fix. You can just take some foam and weave it inbetween your strings up by the headstock behind the nut

Where you been!! Ya steal one of your girlfriends hair scrunchies and use that...A. Wood approves.... Not what he uses it for but...