• From: Nova Scotia, Canada
  • Registered: 2013-01-20
  • Posts: 4,083

Topic: Amplifier Noise?

My Peavey has developed some noise that I'm not sure about, so hopefully someone can provide a suggestion as to where I might start looking. First of all, it has nothing to do with guitars or effects gear, because it make the same sounds with everything unplugged.

It's a bit of an intermittent snowy sound, similar to dirty guitar pot when it's being turned, or a cord starting to go bad. I'd thought about uncapping all the switches and giving them a shot of DeoxIT to start with, and then going deeper until the noise is gone. Any other suggestions about what I could be looking for? A trip to the shop is likely in order, but if it's an easier "home fix" I'd like to try that first.

Many thanks in advance!

  • From: The Land Of Song
  • Registered: 2007-12-10
  • Posts: 5,644

Re: Amplifier Noise?

i play a peavy bandit which i've had years and years. i had the same or similar prob with noise, turned out to be the reverb knob. just turned it off....sorted.

it may not be the same problem. also check if the power lead has gone near the speaker or connecting leads.

Ask not what Chordie can do for you, but what you can do for Chordie.

Phill Williams's Website

  • From: Nova Scotia, Canada
  • Registered: 2013-01-20
  • Posts: 4,083

Re: Amplifier Noise?

Thanks, Phill ...

I got a can of DeoxIT this morning, and cleaned out all of the knobs, etc. No change or improvement. When I went to the next step of cleaning the tube sockets, I noticed that the 12AX7's (preamp tubes) were showng plenty of heat stress. I called a guy I trust at our local Long & McQuade's music store, described the tubes, and he confidently said, "There's your problem." I'll pick up the 3 new 12AX7's that I need and replace my worn tubes, and things should be go to go.

I do appreciate your insight ... many thanks!

4 Reply by unclejoesband (edited by unclejoesband 2016-02-09 02:28:21)

  • From: SC Pa
  • Registered: 2014-03-26
  • Posts: 1,348

Re: Amplifier Noise?

Tenement Funster wrote:

I need and replace my worn tubes, and things should be go to go.

I didn't know tubes could be "worn". I thought they either worked or they didn't.

When I was a kid we had tubes in our TV. I remember my dad occasionally taking the back off it when something wasn't working right. While warning me not to  touch anything, he would point out a tube that wasn't glowing. He would take it out and then we were off to a store called Tri-State. They had a tube tester. There were dozens of prong configurations on it.  Plug the tube in and it would tell you whether it was working right. He usually knew that beforehand but always plugged it in just to be sure. Alongside the tester there was a rack that held hundreds of tubes. He would grab a new one and head home to fix the TV.

__________________________________
[b]Today Is Only Yesterdays Tomorrow[/b]
  • From: Nova Scotia, Canada
  • Registered: 2013-01-20
  • Posts: 4,083

Re: Amplifier Noise?

I'm not an electronics specialist by any means, UJB, so have to rely on others who are ... an awkward place to be!

Apparently, solid state circuits either work or they don't, but tubes can go bad and show symptoms over time. They can squeal, hiss, hum, pop, etc. Or the tone can get lower, dirtier, noisey, rattle, etc. I carefully pulled all the tubes from my amp last evening, and am going to have them tested before forking out approx. $25 each to replace them (3 - 12AX7's and 4 - 6L6's). There could be other causes of this intermittent snowy / static sound I'm getting, but everything I read and everyone I ask tells me to start with cleaning the pots and tube sockets (done), and then check the tubes themselves.

The cool by-product of this exercise is that I'm learning some things as I go, which is always rewarding in itself.

  • From: Probably Somewhere
  • Registered: 2010-12-09
  • Posts: 2,446

Re: Amplifier Noise?

Glad you got good advice. I was going to suggest re-tubing it. Tubes can get also go microphonic, where they squeal and squeak. It's horrible.

  • From: Western Oregon,US
  • Registered: 2008-07-22
  • Posts: 2,498

Re: Amplifier Noise?

Tenement Funster wrote:

I carefully pulled all the tubes from my amp last evening, and am going to have them tested before forking out approx. $25 each to replace them (3 - 12AX7's and 4 - 6L6's).

Are you sure????  Shop around for those tubes before you mortgage the farm.....  I really think you can beat those prices on-line.  Sovtek and Svetlana tubes are very good (the Russians still use lots of "valves" in their electronics, less prone to EMP damage).

"what is this quintessence of dust?"  - Shakespeare
  • From: Nova Scotia, Canada
  • Registered: 2013-01-20
  • Posts: 4,083

Re: Amplifier Noise?

Thanks, Doug ...

The price of tubes (and a lot of other things) has been drastically affected by the difference between the US$ and the CDN$ these days. Something that lists for $20 through a US website will easily cost me $30 by the time it gets here. So naturally Canadian retailers are affected, and this drives up our wholesale prices, and our retail prices in the process. All of the tubes right now (Sovtek, Tung-Sol, JJ, Groove, Mesa, EH, Ruby, etc.) are between $25 - $35 CDN, no matter where I've looked.

For example, a GrooveTube 12AX7 lists at $17.99 on Sweetwater's site (then there'd be shipping & customs charges on top of that). $17.99 US$ converts to $25.99 in CDN$ which is what the local Long & McQuade music store sells them for ... and no shipping costs 'cuz they're only a few blocks away from me. A couple of other online stores (Tube Depot, Doug's Tubes, etc.) are also affected by this currency exchange problem. About 3-4 years ago, the CDN$ was higher than the US$, so the advantage came this way. Gotta love economics, eh? lol

  • Registered: 2006-03-04
  • Posts: 5

Re: Amplifier Noise?

If you can take a wooden pencil or a chopstick and tap the preamp tubes lightly while the amp is on and being noisy you can probably figure out which tube is making the racket. Be careful not to tap very hard though!

  • From: Nova Scotia, Canada
  • Registered: 2013-01-20
  • Posts: 4,083

Re: Amplifier Noise?

Thanks, TP ... I saw that tip somewhere, and it was helpful. I had a wooden tongue depressor, and one of the tubes was "microphonic" when I pushed at it. The new tubes are in, and it's quiet and working great now.

  • jono43
  • Junior Member
  • Offline
  • From: woking town surrey uk
  • Registered: 2016-04-25
  • Posts: 1

Re: Amplifier Noise?

Jono43 from the UK
Hi Guys, valve (UK) or  tube (USA) amps are great for kicking ass. The tubes do 'burn out' after some time and then they will have the appearance of an old dim light bulb, i.e, blackened inside the glass envelope. This is caused by the 'element' getting very hot and depositing some of itself on the glass. So do a quick visual check of a tube / valve - if it is blackened inside then it is a time to change it as it is degraded. This is how we checked out the early UK valve radios before transistors came along. Be safe and play hard!