Odd noise in Peavey tube amp / bad earth??

[Dave Sloven]

I turned on my Peavey 6534+ - which is only a week old - and heard an odd popping noise when the amp was first switched on, and then a constant cyclical noise like a soft water drip sound blip blip blip repeatedly as long as the amp has the standby lamp on, but not in the clean circuit of the rhythm channel, only when 'crunch' is engaged or on the lead channel, i.e., when a gain circuit is engaged.  Has anyone else had this issue?  Warranty means sending it to Melbourne, and most likely being without it for weeks.

I'm wondering if there is an issue with one of the pre-amp tubes.  The fact that it doesn't happen in clean mode suggests that it's not one of the EL34s.

The preamp tubes in this amp are the same as those in the 6505+, and the 6505 just has one less of the same tube.

I've been really good about warming it up before hitting the standby switch but ...

Only things I've changed recently is that I moved the footswitch board further out into the room, precisely so that I could avoid standing too close to the amp (I was worried that the pickups might feed back).

I let it cool for a couple of hours and turned it on again just now and it's doing the same thing.

This kind of stuff always seems to happen to me just when I've spent a big wad of money on something (in this case a set of BKP Warpigs).  Maybe it's some kind of jinx!

Anyway I'd value your opinions before heading over to the Peavey fanboy forum and asking there

[Dave Sloven]

Well, I went back to it and found that it was making this noise on all of the channels, clean included, and that it was just that the rhythm channel was not loud enough with the crunch out for me to hear this noise.  I turned the post volume up a little and there it was.  I think now that the most likely culprit was a power tube.

I then went out for a few hours and when I got home I turned it on again.  This time there was no popping sound when I turned on the power, and no dip dip dip sound.

I'm wondering if this is something to do with the fact that it is winter here and the amp is located reasonably close to a window?  It might be that one of the power tubes got a little too cold and that affected start up.  I'm keeping that curtain closed now in the hope of insulating it more from the cold.

If anyone has had this experience with EL34s please post about what happened and what you did about it.  Apparently the bias adjustment on Peaveys is always too cold from the factory.  Could this be a factor?

[Toe-Knee]

I've had a very similar thing happen in the past and it turned out it was just when my fridge was kicking in. Once the fridge went back into i guess its normal state the noise didn't happen on the amp.

I solved it by getting a filtered mains adapter.

[Dave Sloven]

I've had a very similar thing happen in the past and it turned out it was just when my fridge was kicking in. Once the fridge went back into i guess its normal state the noise didn't happen on the amp.

I solved it by getting a filtered mains adapter.

That's very interesting.  It definitely had a sound that was like power cycling.  I'll look into getting one of those.

[Alex]

Also, I assume you've checked if it makes it with no leads attached (i.e. it's not picking up some noise from the cables)?

[Dave Sloven]

It might be the cable.  While it was fine before on the old amp with the 90 degree end into the amp, on this amp I have to put that end on the guitar.  It's possible that it is in the relation between the new high gain amp and the cable, or because the angled end creates issues vis-a-vis the the control cavity in the guitar.  Either way the noise stopped when I took out the cable from the amp end.  I have another cable I can try but that may be as bad or worse than this one.  Could be time for a new cable!

I tend to step on it a bit too which might not have helped.  :?

[Dave Sloven]

Yesterday this noise started up again, and I have been noticing quite a bit of other noise on the lead channel as well.  So I dragged out my old Roland solid state practice amp, and the noise was there too.  I thought maybe it was a dodgy lead, so I tried switching from the bridge pickup (A-bomb) to the neck (Cold Sweat) and back again.  I could only get the noise with the A-bomb.

I'm thinking that it could be one of two issues:

1. a bad earth in the guitar on either the volume or tone pot for the bridge pickup
2. a shielding issue.  There is no shielding in there.  I've thought of a couple of possible fixes.  One is an adhesive foil on the underside of the access cover, though this seems minimal.  A more radical solution being to paint the cavity with a shielding paint, e.g., a copper-based paint.

Have people found the latter to be necessary with higher output pickups like the Nailbomb?  It's odd that the neck pickup isn't doing it, as that is fairly hot too.  I'm guessing it is a bad earth - and I'm taking the guitar in a for a set-up this week and will point this out - but do people have experience with issue 2?

[Dmoney]

I use an alnico nailbomb in both a "shielded" guitar and "non-shielded" guitar. (Les Pauls).
The non shielded is a typical les paul custom setup.
The shielded is a les paul custom with control cavity and pickup cavity adhesive copped sheeting.

I have no noise issues on either. Unless I'm really close to the head and I start picking up the noise radiated by the amp, but that doesn't count. Or close to a laptop. Or my phone is in my pocket behind the guitar and someone calls me etc...

[Dave Sloven]

Thanks for the reply.

I have  to go to Sydney for ten days from the end of this week so I'm taking my SG to the tech before then to have this, the fretboard, and general set-up looked at, so hopefully he can find the source of this problem. One thing I'm glad to have worked out is that it's not the amp.  It might be the wiring in the house, as the former owner thought he was really good at doing all kinds of things himself (his ego wouldn't allow him to hire an electrician, it seems) but I'm hoping it is just a solder joint in the guitar.

[Dave Sloven]

I still have this drip drip noise in my amp after trying everything so it is going in for a warranty service before the three months warranty on the tubes expires.  I suspect it is one of the tubes.

A filter has been fitted to the power outlet, it does it with both of my guitars (shielded and unshielded) and seems to be getting worse.  Anyway I contacted the retailer and they say that AMI have been told by Peavey that they have to honour warranties on Peavey products sold by the previous distributor (as you would expect).  The twerp I spoke to at their local retail store (actually he wasn't technically a twerp, he was more experienced and mature than that, but the word I would use would probably be censored) said that only the items they sold would be serviced by AMI and the older units would be serviced by whoever the previous distributor arranged; little did he know.  Anyway I spoke to Peavey and my retailer and AMI have since been told the score.  You take over distributor rights you also take over distributor obligations!