Peavey XXX Gain Noise

[drdoom8793]

Hey guys! :hello:

So I'm having some issues with extra noise on my Peavey XXX head. When ever I'm running the crunch channel (lighter, more old school british gain), it's clear as day, no background noise. However, when I switch to the Ultra channel (heavier, more modern gain, in the vein of a Mesa Rec), I get a lot of noise when I'm not playing. I'm playing through my SE Singlecut so it's not like I'm using single coils or coil splits. It's obviously not the newest amp and I've never changed the tubes on it since I got it so I suppose it could be that, however, the tubes all seems to be functioning correctly, so I'm not sure. I've never tried using a noise gate on it, but I use very few pedals before the amp and they don't give me any problems on my smaller practice amp so I don't believe that would be the source. I'm no amp expert so I was hoping you guys might have some suggestions.

 

[vchizzle]

Most likely a tube. You can "test" the tubes by having the amp on & gently tapping on the tubes one by one with a pencil eraser. If you get any crazy hiss, swoosh or ringing that'll let you know which tube is bad. I've played that amp,not extensively, a long time ago and I don't think you should need a gate on it. I don't recall it being that noisy. I'd start with the tubes and see what you find.

 

[DHW]

Gain is noisy... A failing tube in the gain stage activated with the channel switch could contribute. Less than perfect shielding in the guitar could contribute. A low quality or damaged cable can contribute. Is your practice amp solid state? If so they are going to be quieter just by their design. When you increase the gain you are boosting the signal as you know. When you increase the gain even the most minute signals can come through and often will as static. Subtle string vibrations, interference, radio frequency bleed it all gets boosted. Do you have a tuner in the chain? Move it to the very front and see what happens when you kick it in, does it get quiet? If so the problem is either the cable or the guitar. If it doesn't get quiet move it to the very end of the chain. If it gets quiet there then the problem is somewhere in the chain. Move it one step at a time until you find either a bad patch or a noisy pedal. A noisy pedal could be improper shielding, poor design, or a ground loop, try it with a battery. If it does not get quiet at the end of the chain then try replacing the cable from the end of the chain to the amp. If that does not correct it try it on a different power outlet. If that doesn't fix it then look to the tubes. Is the amp self biasing? If not check the bias(maybe do that as the first step if you are comfortable doing it yourself). If it's still noisy then it's just the amp and not much you can do about it unless you want to have a shop start replacing stuff in it which would likely end up costing more than selling it and buying something better.

edit*** tapping the tubes is a good place to start as was said as it is easy, free, and may not even have to move it.

 

[drdoom8793]

Thanks for the advice! So I just tried plugging straight guitar into amp, no pedals. Even with the volume down on my guitar, it's still giving me noise. Tried this with a couple different cables with the same result. I'm going to try the tube tapping test (say that 3 times fast) and see if that is the issue. I'll let you know what I find out! Thanks again! :beer:

 

[Brad737]

Like DHW says, gain is noisy. My Peavey 5150 used to sound like an idling jet engine, even when I wasn't playing. And the XXX can be noisy too. Here are two easy, and fairly inexpensive tricks you can try.

I swapped the V1 and V2 tubes for 5751s instead of 12AX7s. That's the old SRV trick. I tried others, 12AT, AU, AY...but i didn't like the tone with those. The 5751s sound great, but only have 70% of the gain of a 12AX7. Don't worry though. With those cascaded gain stages, there's still more than enough gain to melt your face off.

You may also try the ISP Decimator G-String, and run that through the effects loop. Great piece of gear that doesn't break the bank.