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-   -   Help! Valveking problem! (http://www.ultimate-guitar.com/forum/showthread.php?t=963011)

pac108 09-21-2008 10:11 PM

Help! Valveking problem!
 
I have a peavey valveking 112 that has worked fine for 4 months until recently when it decided to start making a high pitch squeel whenever it is on and the standby switch is on.

I have put a new speaker in it, an eminence private jack.

It doesnt matter if there is a guitar plugged in or not. Anytime it is on it makes this high pitch hum/squeel. When i flip the standby switch to standby the pitch of the squeel lowers until it is silent. It sounds like a jet engine shutting down. Flip the standby switch back up and it starts low and gets high again. This noise stays steady in pitch and volume.

I've looked at the power tubes and they aren't a weird color or anything. They have a bluish tint when the standby switch is on but it has always been that way.

I checked the preamp tubes and none of them are cracked or anything.

Anybody have any ideas? I think this would be covered by warranty but if its something simple that i could fix I'd like to avoid the trouble of having the warranty fix/replace it.

Any help would be greatly appreciated.

Kevin Saale 09-21-2008 10:13 PM

Sounds like a noisy preamp tube. Try switching them around, it's probably the one in v1 or v2.

Wrst_Plyr_Evr 09-21-2008 10:18 PM

I don't mean to hi-jack the thread, but is it bad that I leave my stand-by switch and my power switch on at the same time? what's the stand-by even do? I have the same amp if it matters.

Kevin Saale 09-21-2008 10:24 PM

The standby is to warm up the tubes and make them last a little longer. Its more convenience than necessity. If you want your tubes to last a bit longer turn the power switch to on, while the standby switch is still set down to standby or off or whatever. Let it warm up for 30 seconds and then flip the standby switch to on.

311ZOSOVHJH 09-21-2008 10:39 PM

pac108 - that does sound wierd. Are you sure it is not your guitar. Can you validate that? Same with environment, can you validate that nothing has been added. Pedals, florescent lights, etc?

What happens if you use the second input jack?

pac108 09-21-2008 10:51 PM

Well Kevin, you are the man. That fixed it. Thank you tremendously. Wish I'd have known that friday. I had to play two shows with a crappy ibanez SS.

Would it be a good idea to get some new tubes?

Also, I've been thinking about making it into a head. is this a good idea? anything special i need to be aware of?

Kevin Saale 09-21-2008 10:58 PM

New tubes would be a great idea, the stock tubes it has are rubbish. Not worth it to make it into a head, just get an extension cab and use the speaker out.

pac108 09-21-2008 11:03 PM

One more thing Kevin and thank you for all you help. What would be good tubes to replace them with?

Well, two more things. Is there a tube amp toubleshooting list somewhere? It'd be nice to have something to look up a problem and have possible solutions.

Kevin Saale 09-21-2008 11:14 PM

I'm not sure for that amp, zoso could help you better.

I can give you a quick trouble shooting guide, not totally comprehensive but a good place to start

First and foremost, eliminate the guitar, pedals, and cables out of the equation, try a different cable and a different guitar to make sure the ones you're using aren't causing the problem.

Insure that the amp is on and plugged in, seems like a no brainer, but I've seen people mess this up. Insure that the volume is turned up on the guitar and the amp.

If the amp doesn't turn on at all it's more than likely the fuse blew.

If the amp turns on, but the tubes don't light up, you may have blown the HT fuse, not as easy to change as the mains fuse since it's in the chassis many times. Depends on the amp.

If you have screeching feedback or high pitched noises and you're sure it not the pups in your guitar then you have a microphonic preamp tube, switch the input position with the phase splitter or something for a temporary fix, but order some new ones. Get a balanced tube for the phase splitter.

If you have volume fluctuations or the tone just generally seems dull, you probably have power tubes on the way out, possibly dying preamp tubes, but the power tubes generally only last half the time as preamp tubes. Power tubes generally last 1-3 years depending on usage, preamp tubes can be good for 3-5. NOS tubes will typically last longer with some examples of preamp tubes able to last decades.

If you smell something burning or see smoke, turn the amp off IMMEDIATELY and have a tech look at it.

Always make sure the cab or speaker is plugged in before you turn on the amp. If not you will at the least fry your power tubes and at the worst totally destroy the amp. This is not good.

When you replace power tubes make you bias the amp (VKs and peaveys in general don't need to be biased though) or order tubes that are designed to match the bias of your amp if it doesn't have a bias adjustment pot. Cathode bias amps (like the VK) need no biasing.

That's all I can think of, and while I must be missing something those are some good things to check over before you go to a tech or post here. I'm not saying don't go to a tech or don't post here, but 95% of the time going through that list will probably solve your problem.

pac108 09-21-2008 11:29 PM

thanks again man.

311ZOSOVHJH 09-21-2008 11:44 PM

^that was a great overview Kevin.
:cheers:

you pretty much nailed everything. And yes, the Valveking doesn't need biasing. Just plug right in. Lot's of folks will swear by JJ tubes but I read a post on here that now makes me think twice. The comments from Erock were most interesting and it is hard to not listen to what he says. I think I saved it. Wait.

http://www.ultimate-guitar.com/foru...55&page=2&pp=20

Also, check in the Valveking Discussion Thread.
http://www.ultimate-guitar.com/foru...ad.php?t=737907


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