Author Topic: Power tubes failing? (Read 6656 times)

maliciousteve · « **on:** June 13, 2006, 06:00:32 PM »

Hey. Just been playing through my set up and it just started to crackle and pop randomly. Turned off to stand by, turn back on again and it started popping and farting again within a couple of seconds. so i guess it's the power tubes.

As i'm going to need new ones. What are the advantages of EL34's? and what are the Advantages of 6L6's?

How easy are the tubes to change in a Peavey Classic poweramp?

CaffeineJunkie · « **Reply #1 on:** June 13, 2006, 07:11:37 PM »

depends on what tool you use, i personally like to use a hammer or brick...

no idea sorry, but you might wanna make sure that its the power amp valves before you change anything

Twinfan · « **Reply #2 on:** June 13, 2006, 07:51:49 PM »

You sure it's not a dodgy cable or jack socket? I'd check the simple stuff first. Try another cable, then another guitar. If you get the same problems, it's the amp. Try cranking it a bit too and see if it's obviously an output valve rather than a pre-amp valve...

maliciousteve · « **Reply #3 on:** June 13, 2006, 08:19:25 PM »

Yeah i've tried different cables, guitars, settings, cranking the damn thing and the popping etc still happens. Also output 2 of the power amp doesn't work either. Any one know of any amp repair guys near the london area?

_tom_ · « **Reply #4 on:** June 13, 2006, 08:26:36 PM »

Quote from: maliciousteve

Yeah i've tried different cables, guitars, settings, cranking the damn thing and the popping etc still happens. Also output 2 of the power amp doesn't work either. Any one know of any amp repair guys near the london area?

^Bainzy? Although I dont know where he lives...

HTH AMPS · « **Reply #5 on:** June 13, 2006, 09:07:19 PM »

Dennis Cornell is in the London area I do believe (do a google search on Cornell Amps)

:twisted:

FELINEGUITARS · « **Reply #6 on:** June 14, 2006, 12:49:48 AM »

Peavey Classic 50/50 has EL84 valves (x8! 4 per side)

But it may be one of the driver/phase inverters giving trouble - cheaper to try a spare 12AX7 in each position before shelling out on power tubes.

The Peavey amp is a case of taking the lid off for valve access

Be careful - lethal voltages inside!

maliciousteve · « **Reply #7 on:** June 14, 2006, 03:54:02 PM »

well i tried replacing the preamp valves and the problem still occurs. Looks like i'm going to have to replace the output valves.

downrodeo · « **Reply #8 on:** June 14, 2006, 04:03:46 PM »

I hope you're sure it's the tubes. It may be some other abnormality with the amplifier, your cords, guitar's input jack, pedals, etc. :? Take it to a repair guy for a prognosis.

maliciousteve · « **Reply #9 on:** June 14, 2006, 04:54:23 PM »

It's deffinatly not my guitars, cables, pedals etc. It makes the crackling, popping sound even when i dont have anything plugged into it.

Searcher · « **Reply #10 on:** June 14, 2006, 06:27:22 PM »

Hey Steve, I was leaving the tubes question for people here who know more than me about it, but no one's come in to say anything yet, so I'll post my bit.

My amp happily takes either 6L6 or EL34 tubes without having to mess around with it. So I've A/B-ed them before. Now I have to try to remember my impressions! ;) I found the EL34s nicer overall--how's that for specific details: they're nice. Heh. Seriously, they had a slightly fatter sound to my ears. A bit rounder and more mellow, but with a slightly mushier sound, especially when breaking up. The 6L6 tubes seemed more even across the frequencies, but without quite as sweet a tone. It was more even, but something was missing. Damn, I wish I could remember it more clearly! Supposedly, from what I've heard others say, 6L6 tubes are supposed to give you more bass than EL34s, but I certainly didn't notice it with my amp.

steve · « **Reply #11 on:** June 14, 2006, 09:56:17 PM »

Quote from: Searcher

Hey Steve, I was leaving the tubes question for people here who know more than me about it, but no one's come in to say anything yet, so I'll post my bit.

My amp happily takes either 6L6 or EL34 tubes without having to mess around with it. So I've A/B-ed them before. Now I have to try to remember my impressions! ;) I found the EL34s nicer overall--how's that for specific details: they're nice. Heh. Seriously, they had a slightly fatter sound to my ears. A bit rounder and more mellow, but with a slightly mushier sound, especially when breaking up. The 6L6 tubes seemed more even across the frequencies, but without quite as sweet a tone. It was more even, but something was missing. Damn, I wish I could remember it more clearly! Supposedly, from what I've heard others say, 6L6 tubes are supposed to give you more bass than EL34s, but I certainly didn't notice it with my amp.

Did you set the bias each time you changed?
If i remember you have a speed twin like mine?

FELINEGUITARS · « **Reply #12 on:** June 15, 2006, 12:04:05 AM »

The Peavey is a fixed bias amp - no bias tweaking involved

Searcher · « **Reply #13 on:** June 15, 2006, 01:56:45 AM »

Quote from: steve

Did you set the bias each time you changed?

No. :oops:

I didn't have a multimetre handy then, though I do now. Maybe one day I'll do it again properly.

deg0ey · « **Reply #14 on:** June 15, 2006, 09:16:27 AM »

Can the Peavey take both? I know there's some that can do both, but i didn't think the peavey classic was one of them