Peavey Bandit loud popping

[ApeWeevil]

Hi,
I recently bought a Peavey Bandit 112 second-hand that's started popping. Anything that disturbs it, whether it's playing it above very, very low volumes or tapping it, makes it start popping at max volume until it cuts out, gets smacked and stops for a while or turned off.

I'd guess this is a bad connection somewhere on the boards but I have no idea where. I'd rather not go through the mess of having to completely take it apart and examine all of it so i'm wondering how I'd make sure that it is a cold joint and if I can figure out where. On the back of the the amp there's 1/4" jacks for effects send and return, preamp out, power amp in, an external cab and a footswitch. Haven't had the chance yet to mess around with a spare cable plugging it in to different places and seeing what happens and i'm not entirely sure how to go about it anyway.

Might be worth mentioning that i've been having trouble with the footswitch. When I plug it in it stays on the clean channel all the time like I think it should when the footswitch is in but neither switch does anything. I thought this might have been down to a wire being broken inside the cable since the cable was in tons of knots when I bought it but maybe there's something wrong with the jack.
Thanks

[Enzo]

Well, I don;t know how you are going to fix it without taking it apart and all.

I'd agree it sounds like a loose connection. You can plug your guitar into the FX return, or the power amp in jack. Does doing either of those things stop the noise? For instance, if plpugging into the power amp in jack does NOT stop the noise, then we can assume the noise is coming from the power amp circuit or the power supply circuit. And if that kills the noise, then it was coming from the preamp.

That tells you which half of the circuit is involved, but it doesn;t tell you what area on teh circuit board is involved or what parts.

[Andrew L]

Same Problem...

I'm having the same problem as the one described above. I did try plugging into the "power amp in" and the popping did stop. So I guess this means the popping is comming from the preamp. I have a schematic for my amp and would love to open it up and fix the problem. Any more advise on where to look when I get it open?

Thanks,
-Andrew

[Enzo]

Hi Andrew, and welcome. Please just start a new thread for your amp instead of taking over this old dead thread.

Where to start? Ball up your fist and whack the amp. Does it respond? If it reacts, then some connection is loose. And when this thing pops, do ANY of the preamp controls have ANY effect on that noise? That will help locate where along teh circuit the problem exists.

[Andrew L]

Enzo,

Thanks for the reply I’m not to sure how to start a new thread, I’ve never used a forum before and not sure I’d get it in the right place. I just found this with a google search and went from there…

When I hit the top of the amp I hear a soft quiet static sound (not crackly) with each hit. I tried it in every possible switch position and with all the knobs in the 0, 5 and 10 position and there is no change in the quiet static sound at any level, it is always soft and quiet. If the reverb is up I do get an echo when I hit it, but I assume that both these are normal sounds. I did try using different speakers and the amp still pops, and just for the record it does pop with any guitar.

I did notice that when I’m playing and it decides to pop the power light on the front of the amp dims. The pop does correspond to the volume level I am playing at, meaning if the volume is down the pop is not as loud and if I’m playing loud likewise the pop is loud.

The pop is very intermittent as yesterday it popped every couple of minutes from the moment I turned it on. Yet today it only did it four times in 45 minutes, and I had made no changes to the amp. Today as an experiment I left the amp on for an hour just to see if it would pop just sitting idol and it was quiet the whole time. So it seems to only do it when the guitar is being played.

Thanks Again,
-Andrew