I just bought a Peavey Triple X head used, and a Carvin 2x12 cab, and I just recently played it at band levels out of an Ibanez RG1570 w/Dimarzio pickups (Bridge: Tone Zone, middle: SA single-coil, Neck: Air Norton, no effects pedals at all) for the first time. It was vomiting feedback constantly, no matter where in the room I went (even outside the room around a wall), and w/the pickup selector switch in every position. The only to get it to stop was to hit a note, turn the volume on the amp down, or to turn the volume on my guitar pretty much all the way down.
I’ve never had this problem before w/this guitar and I can still play it at high levels out of my Marshall JCM800 without any problems. The Peavey Triple X sounds great as long as it’s not feeding back.
So, I have a few questions:
1)How would you recommend I remedy this?
2)what exactly causes feedback? I know what it is essentially, but what kind of specific problems in a guitar setup will cause it to be so pervasive? Faulty cables, faulty tubes, faulty pickup grounding, pickups set too high or too low? Things like that.
3)Can anyone recommend a good noise gate? A good one should eliminate my feedback problem if nothing else does, correct?
4)Can anyone recommend a good guitar board? Is there an equivelant of a Straight Dope for guitarists?
sleestak basically explained feedback. If you’ve got enough gain in the loop anything will feedback, if you took the strings off the guitar and cranked it loud enough the pickups would squeal all on their own. Pickups with loose coils or covers can be unusable becase they feed back so easily - hence the dipping in wax malarky.
But it sounds like it’s not the guitar feeding back at all because 1) you say switching pickups makes no difference 2) It works fine with a different amp.
Is it a valve (tube) amp? Pre-amp valves can and do go ‘microphonic’. If you can get at the valves bodies safely you can for test this by tapping them, a valve that has gone microphonic will give you a clear bonk or boing.
A noise gate isn’t the way to solve the problem. Are you sure the noise actually is feedback and not some other interference?
Yeah, it’s all tube. That’s a handy little test, and I’ll perform it soon as I get a chance.
I’m pretty sure. There was another guitarist, a bass player, and a vocalist all plugged in right next to me when I first discovered it, so I suppose something could have been interfering, but I have the same problem in my room, w/all the electronics turned off. Plus, it sounds like stereotypical feedback.
I did the test, and none of the valves made any sort of boingy noise. You meant the valves themselves would make the noise right? I’m assuming you don’t want me to tap the valves w/the amp plugged in to see if any boing comes out through the speakers.
I don’t have a soldering iron, so I’m hesitant to try any potting.
I’ll experiment w/pickup height when I get back from school, but I was hoping to find another solution, as I really don’t want to degrade tone. We’ll see what I can manage.
No, that’s what you gotta do. Let the amp warm up for a few minutes, and set it for mid-volume, (leave the guitar plugged in, but on the lowest volume - amps don’t like unloaded inputs), then tap each tube GENTLY, but firmly, with something hard and insulated, like a wooden spoon. To be extra safe, put your otherhand in your pocket, to prevent yourself from accidentally touching something inside the amp chassis - an old TV tech trick.
Er, yes actually. Just a tap, not a whack. Use a pencil if you’re worried about getting shocked Some of the pre-amp valves may have a metal shield clipped over them, you’ll have to take this off to test/ding the valve.
I can’t see how pickup height could make any difference if it’s not the strings that are feeding back. Try tapping each pickup to see if any of them are over sensitive.
OK so someone’s posted while I’m writing this but I’m submitting anyway.
Disregard that smiley, there’s nothing funny about getting an electric shock. You won’t get a shock off a valve (I can’t bring myself to use “tube”) body since it’s glass, but if you want to be extra safe use Q.E.D’s spoon in you right hand and stick your left hand in your back pocket.
True enough, but there’s always the slight chance of slipping and hitting something that’s live - and there can easily be points with 600 V or more inside tube equipment - hence my recommendation.
There are four big valves, and what look to be four smaller ones w/metal shielding like you describe. I take it the smaller valves are typically the pre-amp ones?
I’m just killing a few hours at school right now, so I can’t do any of this until later tonight (I bet my neighbors loves all the feedback experiments I’ve been doing at night. That’ll teach 'em to wake me up with bagpipes on the weekends), but I did try silencing the feedback by placing my palm over the strings while over at my friend’s. It worked to a small extant, but I had to push the strings down enough to where I suspect it might have been my hand sheilding the pickups from noise which was silencing the feedback, rather than the arresting of the strings.
Also reading over that site about potting Earthworm Jim shared with us, I was reminded that my pickups are mounted not-so-securely. The pickups only make contact w/the rest of the guitar by the two screws which hold them in place (well, and the wires too, obviously). They are essentially floating in midair. The neck pickup in particular looks wobbly, and prone to vibration. Is there any chance the pickups could be vibrating causing the problem?
Looks like I’ve got a lot of tapping to do when I get home.
I did the tapping, and there’s no boing to speak of. One of the smaller valves made a slight knocking sound – nothing even close to a boing – come out through the speaker, but the rest of them were dead silent. Could there still be a problem with that one?
No pickup made any more noise than the others when tapped.
Reading through those reviews, it seems my problem’s somewhat of a common one when playing this amp through hot pickups.
I’m just gonna try out some noisegates, I suppose.
