#1
So i finally got a free rehearsing space at my local church. I set it up and started playing at extremely low volume and on clean. about 0.3 vol. It was great until the rest of the band turned up and a few spectator, then i noticed some cracking. I thought it was the guitar cable but then the volume went and i had to turn it to 5 to get the same volume. I stoppped for a while and then noticed that the two tubes on the left (looking at the amp from the front) glowed reder than red. I mean really red. You've never seen this kind of a glow. then there was no sound ever again. The amp still powers up and goes on stand by but there is absolut no sound. Can someone tell me what this is as I dont want to go out and buy four 6l6gc's to find out it is something else. Thanks for the help guys.
#2
My 5150 stopped working the other day, it was a blown preamp valve, if you have any spares try swapping them out.
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Peavey 5150
1994 Ibanez Jem 7V
#4
Quote by khaine31
I mean really red. You've never seen this kind of a glow.

Yes I have. lol

In my case, the bias was way off.

Take the two that were glowing red out. Take the other two and put them in the middle positions and see if it fires up, then try the outer positions. If it works and no problems, then the tubes are bad. If it doesn't, something is wrong with the amp (or if one in one of the left positions starts glowing red again).

That's what I'd do anyway...
"Practice doesn't make perfect. Perfect practice makes perfect." -some dude
Last edited by Prime2515102 at Mar 10, 2013,
#5
yes i thought that but the valveking operates a fixed bias by by resistors or caps or something. either way it can be altered in the conventional way or drift out like some other amps.
#6
Quote by khaine31
yes i thought that but the valveking operates a fixed bias by by resistors or caps or something. either way it can be altered in the conventional way or drift out like some other amps.


What's odd though is that it's only 2 tubes. There's usually only 1 bias adjustment and it's for all 4 isn't it?
"Practice doesn't make perfect. Perfect practice makes perfect." -some dude
#7
The tubes are red plating.

Replace them and any blown fuses, retest. If they start to go red again off to a tech for repair.
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.
#8
Quote by R45VT
The tubes are red plating.

Replace them and any blown fuses, retest. If they start to go red again off to a tech for repair.

This

Don't play it like that again until resolved.

And the VK is non-adjustable fixed bias (you don't need to bias it)

They probably red-plated for a reason so I'd take it to a tech.
#9
ok sure i'll try that "take two tubes out" test. but im sure that it only works with all four tubes in anyway, otherwise it could be used like this to make it in effect 50watss instead of one hundered.

Guys thank you very much for your advice. I hope its not a tech job as it will be tubes, diagnosis = £??, part needed £??? and labour £??? ughhkkk.
#10
I don't think you can run Valvekings on half power/half tubes like that. Maybe ask in the Only Valveking Thread or email Peavey. I would order a matched quad of new tubes and keep the two good ones as spares. I'm guessing your fuses are fine for now but get some spares of those too.

Put new tubes in and then watch them closely as you play. If it happens again you know you have different problems.
#11
A) you can't run the VKs on half power, because the heaters are wired in series.

B) first impressions.... crackling and redplating? PI coupling caps opened. take it to a tech

C) techs don't have to cost the earth, find a good one who doesn't overcharge (or move to Plymouth and use me ) If my initial diagnosis is correct you're looking at about an hour's work, the diagnosis confirmation won't take long either, and the parts should be alright price-wise, but I may not be correct
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Last edited by GABarrie at Mar 10, 2013,
#12
Quote by GABarrie
A) you can't run the VKs on half power, because the heaters are wired in series.

Well that's stupid...
"Practice doesn't make perfect. Perfect practice makes perfect." -some dude
#13
yes, yes it is, it is THE biggest arse up peavey ever made in an amp design
Epiphone Les Paul Plus Top
Jet City JCA5212RC (SLO Modded)
Ibanez WD7 Wah
Mad Professor Sweet Honey Overdrive
TC Electronic Flashback Triple Delay
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#15
Quote by 311ZOSOVHJH
What's stupid is giving a bunch of advice that you are really not sure on.


His advice wasn't as bad a bigbazz or whatever his name is. He gave even worse- going after a preamp valve when the PT were red plating.
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.
#16
Quote by R45VT
His advice wasn't as bad a bigbazz or whatever his name is. He gave even worse- going after a preamp valve when the PT were red plating.

Not in my opinion. Swapping preamp tubes wouldn't hurt the power section any further.
#17
Quote by 311ZOSOVHJH
Not in my opinion. Swapping preamp tubes wouldn't hurt the power section any further.


Powering it on with the fuses intact will. The more on time you have the better chance of killing something else in the PT section.
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.
#18
The fact that both tubes on the same side red-plated at the same time hints to me that it's something wrong with the amp. Possibly a nonfunctional component in the power sections circuitry.

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Last edited by Tremolo Bum at Mar 11, 2013,
#19
I've blown my amp in many ways in the past, never seen what you class as "Red" plating, the valves in my 5150 always look bright red when it's running due to it being biased quite hot. I've seen valves blowing up in a flash before stopping working straight away, that took a fuse with it and I had to run the rest of the tour on 2 valves 60watt, replaced the fuse of course. I also had a time where it wouldnt power out of standby, that was also a blown fuse.

The only situation I've come accross where the amp would turn on AND make some noise (if only small) but be clearly broken was a couple of days ago when a preamp valve blew, first time that's happened to me.

What I said to him wasn't advice, it was a suggestion that worked in my case with a similar issue, could be that there are other issues poweramp related going on but in that case it will likely blow a fuse before it damages your amp.

If you're not comfortable working with the amp then really you shouldn't be asking advice on how to fix it or what could be wrong and instead be booking it into an amp tech.


I'm assuming this is what you're talking about.

http://www.youtube.com/watch?v=9SfJJ8A8XNM

Never seen it before where the actual metal of the plates are glowing bright red from heat.
Cornford Hellcat
Peavey 5150
1994 Ibanez Jem 7V
Last edited by Bigbazz at Mar 11, 2013,