#1
So in the last few months, I've noticed that my 5150 II has gotten significantly more noisy. At stage volume. I can't have the gain higher than 2.5 without there being some kind of feedback. And that's with a noise gate! Now at that point, all I get is a tiny little squeal before it disappears, but I used to run the same setup with my gain closer to 4 and never have this issue. (just a heads up, I'm running a ts9 up front as a boost, into an is decimator) and the feedback is even worse when I bypass my pedal board and just go direct in. And that's with my gain around 3-3.5.
What do you think it is? I've tested all my cables and gear. There aren't any shorts or anything. My only guess right now is that I should just replace my tubes. It's been over a year and a half and I've done a lot of touring this year. I just haven't done that yet because I haven't seen any signs of the end of the tube life, other than maybe the noise.

Thanks!

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#3
its definitely not the guitar. it does this with all of my guitars. I've also got my guitar shielded completely, so it definitely shouldn't be giving me any noise

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#5
Quote by New_Crisis
its definitely not the guitar. it does this with all of my guitars. I've also got my guitar shielded completely, so it definitely shouldn't be giving me any noise

It's at least one of your pre-amp tubes. They can go out at any time. It's probably one closer to the left side, as the 1st 3 tubes have more to do with your input signal.

Take out one tube at a time, do a visual check. If none of them look blown, then get a new tube and try it in different spots to see if the problem goes away.
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#6
It bound to be a preamp tube as the others have said. Yours are located in the back behind a 6 screw panel. The are laying down, not standing up on your amp. Get some replacement ones, JJ's 83's and maybe 1 JAN5751 or JJ803 for V1.
Quote by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
#7
So I finally got a chance to test the tunes and literally every one of the preamp tubes made noise. Is it possible that they are all microphonic? Or is that somewhat outlandish? Maybe a grounding issue that is causing noise as a whole? I didn't think to try tapping anything else to test that theory before I left our rehearsal spot, so that's next on the check list. I was about to replace my power tubes, it's about that time haha. But I definitely would prefer to not have to buy another full re tube kit if I can help it. I replaced every tube about a year and a half ago with all jj's.

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#8
That preamp PCB is pretty thin. If one tube was REALLY sensitive to microphonics it could be making noise due to the board flexing. V1 will always have a smallbit of microphonics to it just because it is the first gain stage.
Quote by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
#9
So I started swapping preamp tubes around to see if it made a difference and I narrowed my problem to one of the sockets in particular. I started cleaning it with contact cleaner and it reduced the noise a little bit, but no matter which tube I put in there it's still microphonic. None of my tubes make much of any noise in any of the other sockets though. I'm probably going to drop it off at my local amp shop and have them take a look at it. My question is, are there any other things I should do at this point?

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#10
Quote by New_Crisis
So I started swapping preamp tubes around to see if it made a difference and I narrowed my problem to one of the sockets in particular. I started cleaning it with contact cleaner and it reduced the noise a little bit, but no matter which tube I put in there it's still microphonic. None of my tubes make much of any noise in any of the other sockets though. I'm probably going to drop it off at my local amp shop and have them take a look at it. My question is, are there any other things I should do at this point?


How microphonic? Can you see the writing next to it? V1 is going to have a microphonic characteristic no matter what tube is in there. It should be present, but not too bad.
Quote by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
#11
It is v1, but the noise is really bad. Like if I were smacking a cranked up microphone into the palm of my hand.

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#12
Quote by New_Crisis
It is v1, but the noise is really bad. Like if I were smacking a cranked up microphone into the palm of my hand.


If the noise is a pop or crack then most likely it's a bad socket contact. Should be easy for a shop to replace it.

If it's not a pop or a crack it may be normal. Any friends with a 5150 near you?
Quote by DeathByDestroyr
See, it's important that people clarify when they say "metal", because I pretty much always assume they are a Cannibal Corpse fanboi.
#13
Does the amp feedback without anything plugged into the input?

Normally a very microphonic preamp tube will squeal/feedback with the gain & volume both up & nothing plugged into the input. With the amount of gain that's available in the 5150, the pencil tap test will be hard to tell if the tube is microphonic, especially in the v1 spot.

Try moving the tube in v1 in various different spots & try each of the tubes in those spots in the v1 spot as well, start with the one at the end v5,v6 (whatever the last preamp spot) first.
#14
Not feedback really, but the normal 5150 preamp hiss. I get a little hiss on the clean channel as well...but it's nothing compared to the dirty channel. today I'm going to do a thorough clean of all my tube sockets and replace two of the preamp tubes because the pins are bent. Hopefully that will clean everything up! I haven't cleaned anything in a year and a half, when I did my last re tube so I suspect that is a huge chunk of my issue.

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#15
Oh I thought it was unsual feedback. Well here is a link Click You could go through it, if the cleaning doesn't help then it's time to take it to a tech.
#16
Cleaning all the tube sockets and replacing a few preamp tubes with bent pins solved about 95% of my issue. I'm still getting a bit of a squeal with my tube screamer on, buy only when I have the amp past 3.5, which is plenty loud already.

Check out my band! Endeavor


Fender American Deluxe Telecaster (little 59')
Peavey 5150 II
Orange PPC412
Boss NS-2
Boss DD-3
Monster Power Pro 900
Korg Pitchblack Pro
Sennheiser EW 172 Wireless
Carvin 6 space rack
#17
You can sometimes be fooled by a microphonic tube. One could be so bad that it will clearly pick up tapping on another tube - or anywhere on the chassis or that matter.

Buy two tubes. Make one of them a JJ ECC803 if it's a head and run that in V1. That's a low noise tube but don't use one if it's a combo.
Then try the other new tube in each position in turn and listen for a difference. Leave it wherever it sounds best. It's unlikely to be more than two tubes.
You should always have a few spares on hand, for testing if no other reason.

Also don't disregard the 6L6's. They don't go microphonic often but when they do go they make a fine microphone and will do what I described in the first paragraph. If you're lucky it will just be a preamp tube but don't leave out power tubes in your diagnostics.
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Last edited by Cathbard at Oct 10, 2013,