Peavey VB-2 tube buzz?

[negativeions24]

Finally took the plunge into the all-tube world with a used Peavey VB-2. Playing around with it, I've discovered that there is a buzz coming from within the head when I play certain notes, specifically D and Db. The problem seems to go away with volume and cutting the bass/low frequencies. This being my first foray into all-tube, all I've seem to come up with is that I may have a microphonic tube. As far as I know, all tubes are stock JJ's.
I'm curious as to what may be the issue and what is recommended to correct it. Thanks!

[nashvillebill]

There's a difference between microphonic tubes, versus tubes that are just mechanically noisy (which you have). The noise from microphonic tubes gets into the audio signal, causing things like squeals, etc, which you can hear through the speaker. I don't think your tube is microphonic.

Any amp, even solid-state, can have components like nuts, washers, grills, etc which resonate at certain notes--this is mechanical noise. You don't hear this noise come out of the speaker. Check for things like loose screws, components vibrating against something, etc.

Certain tubes tend to be somewhat noisy, they have a little bit of a rattle on certain notes, I've heard this rattle with JJ's in guitar combos (combo amps are especially prone to having the preamp tubes rattle). The internal components sound like tiny little springs rattling. As long as the noise isn't actually coming out of the speaker--in which case, replace the offending tube(s)-- you've got a couple of options.

You can try tube dampers--little high-temperature red o-rings that slip over the preamp tube. They add a little mass and change the resonant frequency, some people have had good luck with them. Look on "that auction site" for tube dampers or maybe spelled tube dampeners.

Poor folks have made their own tube dampers with red high-temp RTV sealant, gobbed liberally over the preamp tube (don't do this on poweramp tubes, too hot). Looks ugly but same principal as the store-bought o-rings.

For a head, try putting some sort of dampening foam between the head and cab. Wally world sells a blue foam pad about 1/2 inch thick that backpackers use under their sleeping bags for like $10 or so and this would give you several layers of foam.

[negativeions24]

Thanks for your reply, Bill! This definitely puts my anxiety at ease. I'll work on dampening and post the results!

[BbbyBld]

This is probably covered under the warranty if it's new. If you don't want to screw with it, take it to a Peavey dealer and get them to check it out.

[hdracer]

Originally Posted by BbbyBld

This is probably covered under the warranty if it's new. If you don't want to screw with it, take it to a Peavey dealer and get them to check it out.

+1 Peavey has a 5 year warranty on that head. Call them & find your local service center and let them fix it. Peavey CS is great.

[negativeions24]

It's used. I've heard of them repairing equipment regardless though. Might give them a call just to attain an overall bill of health.

[jastacey]

Hear is a suggestion, If you find that the tubes are the culprits, and I suspect as such, and you need/want to swap out the power tubes, I'd suggest using the JJ 6CA7, I used to have this amp and after I did the tube swap the sound was more that a little bolder, in the grunt that the amp would deliver ...why I sold the amp ....every thing I own, has a sell price and after I swapped the tubes out, everyone who heard the amp wanted it

[hennessybass]

Might not be a tube issue. When I first read your post, I thought it might be something loose that is simply buzzing when you hit cretin frequencies. You know, like when you are playing in your house... crank the amp up and the pictures on the wall start to rattle. When I play at home, there are particular notes that make the hardware on the coffee table buzz. There are particular volumes that make the mirror by the front door buzz... ya dig?

I didn't really see anything in your original post to indicate that you have a tube issue, or that you problem has anything to do with the fact that it's a tube amp. You have an effect, and the causes are loud volume, bass frequency, and playing two specific notes that are very close to each other... IMHO, you do not have a "tube problem."

[6810]

I agree, a bit too early to tell.

In my room, when I crank the volume on my VB-2, certain notes on my 5-string cause an acoustic I have to rattle to the point of tipping over.

I'd make sure your head is level and that everything inside is as it should be, especially grill etc.