Peavey Classic 30 Popping At Regular Interval

[CloudNine]

Greetings guys,

So I have Classic 30 from about 2002 that recently developed a popping noise that happens regularly every 2-3 seconds or so. For the most part it's faint and stays in the background pretty well, and the amp is still playable. But it's one of those things like once you know it's there, you can't stop hearing it.

If all else fails I'll give it to my drummer to use as a metronome.

Anyway, here's what I've observed so far...

- The popping has been occurring for the past month or so. After I first noticed it, I swapped out/upgraded my speaker and all tubes since that was on my to-do list anyway. Cleaned and checked sockets and everything looked decent, so I don't think anything funky is going on with those components. However, the problem still persists.

- The popping occurs regardless of channel or reverb selection.

- The popping *does not* happen, or at least isn't audible, when nothing is plugged into the input. Additionally, the popping *does not* occur if I have a guitar plugged into it directly with the volume all the way down, or my pedal board plugged into it with say, my compressor pedal on but turned all the way down. If there is any sorta real signal getting to the amp though, and levels are up on my guitar/board, or I leave the loose end of the cable just sitting on the carpet to catch some static fuzz, the popping is really evident.

- The loudness of the popping is indeed affected by the volume controls of the amp.

- The intonation of the popping seems to be affected by the EQ knobs.

- The popping seems to be more pronounced the more gain there is. For instance, if I have the guitar just plugged in directly and switched to both of my not-so-hot humbuckers, the popping is real faint. You really have to listen for it, but it's still there mocking me. If I'm going through my pedal board and switch on my DS-1, or toggle my wah on high, etc. then it's quite a bit more obvious.

Anyone else here ever see this problem? Know what it could be? I suspect that if it's able to be controlled by volume and EQ, and isn't dependent on the channel that the issue is coming pretty early in the circuit. A bad cap perhaps? Grounding issue?

Thanks for your time gents,

- CloudNine

[kkatarn327]

This might be a little far-fetched but could it be that your signal chain is picking up some kind of interference? God knows what kind of RF and EMF are flying around at any one time, and it could be that about a month ago a subtle change occurred in your environment that is now causing this. It's obvious that the popping you're experiencing is induced in the signal or at least related to it. Very strange that it only happens when you have an input plugged in, and further that it is affected by volume controls on your guitar and pedals. That's nothing I've ever heard of before.

Have you tried using your amplifier in a different physical location, away from your home or studio (or wherever you are experiencing this issue)? If not I would definitely try that first, as far away as possible perhaps at a friend's house. Make sure you take your whole rig and set it up exactly how you did when you were experiencing problems. I'm afraid I have no ideas beyond this, I am by no means an expert. This is just the first thing that came to my mind so I thought I'd deposit my $.02. Good luck!

[Jazz P Bass]

#1: these Pvy amps are a b*tch to work on.
#2: you have already discovered that the problem lies before the volume control.
#3: unless you have sufficient skills & test equipment, I have to recommend taking it to a reputable tech.
Really, it could be anything.
A bad cap, a faulty connection, .........

[Enzo]

The clues are all around you. It doesn't do it unless a guitar is plugged in, and even then if the guitar is turned down, it won;t.

It isn;t the amp.

Is your cell phone sitting on top of the amp?

Sit an AM radio, preferably battery operated, on top of the amp. TUne it to a point where there is no station, just background noise and hiss. Does it pick up the ticking?

Plug the guitar in and turn it up so we hear the noise. Does it matter which direction you face while holding the guitar? In other words does "aiming" the guitar various directions change the noise or amount of noise?

A while back, I was working on an amp and it made a sort of grinding buzz for maybe 20 seconds, then it got quiet for maybe 40 seconds, then another 20 seconds of buzz, and this cycle repeated. I went nuts trying to figure out how the amp could do this. I got fed up, left it running on my bench, and walked out the front door of my shop for some fresh air. I just happened to look at the traffic light at the end of the block. EVery time the red light came on for the one direction, I could hear the amp making the noise. Whenever that red light went out and any of the other lights were on, no noise. Ther was apparently a noisy triac in the traffic light control box a half block away, putting this noise on my power line.

Sounds environmental to me.

[CloudNine]

Awesome, thanks for the feedback on this guys!

It's actually at my buddy's right now, so I'll see about getting it home this week along with my same config there and see if it does the same thing. It does pick up my cell phone from time to time, but that's a pretty distinctive morse code hey-you're-getting-a-text noise. Lord knows there a million and one other electric doodads all up in that room though, so perhaps I just need to fashion a tin foil hat for it.

- C9

[skunky]

yo, i got the exact same thing on my older pv classic 50 4/10 amp!!! u find out what the prob was?? thanks, ob

[CloudNine]

Never was 100% sure what it was, but now that I have the amp at a totally different location than before, like, miles and miles and two states away, there's no popping at all. Some of my bandmates stuff eventually started exhibiting the same pops too in that room. The best theory I could come up with is that my buddy's neighbor's electric fence across the street pulsed at about that same rate. So perhaps there was some sorta dirty noise caused by that over the power source. Definitely possible given Enzo's example.

If I was in the same situation I was going to look into perhaps some sorta power conditioner for the amp and give that a shot.