Rattley valves ?

[Emperor Fabulous]

Our rhythm guy has a Peavey Classic 30 and I popped over there tonight to go over a few tunes, and I noticed (apart from finding it difficult to get a non-honky sound out of it at first), that all of the tubes are rattling (i.e. the guts are vibrating against the glass) and it makes a fair racket which obviously will get drowned out beyond a certain volume level, but if it was mine, it would irritate me hugely.

If you tap them gently with your finger you can hear them rattle, and certain frequency notes cause them to rattle like mad with sympathic vibration.

Surely this isn't normal ??

Edit: After a bit of Googling, I've discovered that this is a design flaw and all Classic 30's do it by all accounts. Some chap is even marketing a gadget to stop the rattles - 'Tom's Tube Tamer' - http://my.att.net/p/s/community.dll?...upid=192273&ck

[ecc83]

Morning Emp'

The problem is almost certainly due to the valve retaining clips rattling against the glass*. The fix is to use some heat resistant plastic foam to prevent direct contact twixt glass and wire.

I have a sheet of ~4mm foam that I think is suitable but let me test it on a hot EL34 to make sure. If ok he can have a few sqr cms no worries.

*Had someone told me 3 years ago that output valves can get microphonic I would have said *******s! But in fact it is quite a common problem now. I cannot see however that Peavey would fit such valves in all their amps just to annoy peeps?

Justfort! The foam sheet came with some bit of computer gear that I bought, can't say what or when. So you likely have similar about the gaff. Test it for heat tolerance tho'. This stuff is looking good.....

Dave.

[ICBM]

The problem is almost certainly due to the valve retaining clips rattling against the glass*.

*Had someone told me 3 years ago that output valves can get microphonic I would have said *******s! But in fact it is quite a common problem now. I cannot see however that Peavey would fit such valves in all their amps just to annoy peeps?

The Classic 30 is notorious for shaking valves to bits - the whole chassis is very vibration-prone. Not one of Mr. Peavey's best designs. (It actually puzzles me why this amp is apparently so highly-rated - like the Emperor I struggle to get a really decent tone out of them as well, they sound rather average to me - as well as running very hot and killing valves far too often.) The Classic 50 - which is also a 4-EL84 amp but has them mounted in a foam-padded, fan-cooled enclosure - almost never blows them, by comparison.

I've known about microphonic power valves since 1986 . In that year I bought a Marshall 2x12" combo which had a "blown speaker", except that it didn't... the previous owner had tried changing them to no avail. He sold it to me cheap since he thought it was just knackered. It was a microphonic EL34, that sounded remarkably like a blown speaker! And that was a Mullard, too...

[ecc83]

Well it looks a tho' my foam will not fix THAT sow's ear!
It has stood up to an hour of a very hot EL34 (throughput about 22W) tho' the office grade lakky band melted and stunk the place out!

You are still welcome to some to try. PM me and I will post it.

Dave.

[hywelg]

The problem is almost certainly due to the valve retaining clips rattling against the glass*. The fix is to use some heat resistant plastic foam to prevent direct contact twixt glass and wire.

Not necessarily. The Winged C's (6L6 and the clips contact the base not the glass) in my DrZ rattle internally. Even when not on, another amp in the room will set them off sympathetically vibrating. They sound absolutely gorgeous so I'm not going to change them just because of it.

[Emperor Fabulous]

Thanks for the offer Dave, but I don't think it's a big deal tbh. I'm not convinced it is the retaining clips myself. I held onto one of the clips and tapped a valve with a finger and it rattled - implying that it was the internals rattling against the glass.

[ecc83]

Thanks for the offer Dave, but I don't think it's a big deal tbh. I'm not convinced it is the retaining clips myself. I held onto one of the clips and tapped a valve with a finger and it rattled - implying that it was the internals rattling against the glass.

Ok Emp' but I think those valves are crap and likely to crapout at anytime!

Dave.

[Gagaryn]

I bought a Princeton Reverb at the weekend which has an annoying rattle which I tracked down to one of the power valves. I swapped the power valves around and the rattle followed the valve which makes me think its the valve which is faulty rather than the clip. Phoned the shop where I bought and they were excellent - new matched pair are in the post. I've ordered these though, just in case! http://www.ebay.co.uk/itm/NEW-23mm-T...item256d764186

[Gagaryn]

haha! Just noticed how old this thread is.