Need Opinions. Weird ping on unwound strings.

M

MikeF

New member
I just received a used VHT Pittbull G-50CL head and at this point it's almost unusable. Great sounds but the unwound strings make a very pronounced pinging ugly harmonic sound along with the played note. I know this sounds like a tube problem and I've been in touch with Steve Fryette by email, but wanted to hear some opinions from the folks here who have far more experience than I with tubes.

Are microphonic sounds usually associated with preamp tubes or the power section? I tapped all the tubes while the amp was on and nothing sounded weird. The amp is a little over a year old, but I don't know how hard it was used. I'm playing it through an avatar 2 x 12 with a vintage 30 and G12H30.

Steve recommends a 12ax7wb for V1 and 12ax7 chinas for the rest along with Svetlana EL34's for drivers. Would it be best just to retube it in whole with a bias job? Also any recs for a V1 tube thats a little smoother than the sovtek.
I don't mind retubing but if theres something simple I'm missing I could use the advice.

Thanks all. Mike
 
Re: Need Opinions. Weird ping on unwound strings.

The first thing I'd do is swap one of the 3rd or 4th pre tubes for the one furthest from the power tubes. That way, your 1st stage pre tube is a fresher one, and you can diagnose the problem quick without buying anything.

If you move the pre tubes around in the amp and the problem goes away, simply replace all the pre tubes. In your amp, the best sounding ones are GT12AX7C's or Sovtek 12AX7 LPS, which are far better than other Sovteks. I did a preamp tube shootout, and those two came out on top.

If retubing the amp doesn't solve anything, it's likely that one of the big cannister filter capacitors is causing some wierd ghost notes, and may need to be replaced.
 
Re: Need Opinions. Weird ping on unwound strings.

If I retube should I run the same in all sockets or do you rec something different for V1?

Just did a quick swap on my lunch hour and same deal. I'll try some more combos tonight.
 
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Re: Need Opinions. Weird ping on unwound strings.

If swapping the pre tubes around didn't change anything, I'd let a tech listen to it, and see if he can diagnose it. From what I've been told, filter capacitors going bad can cause ghost notes that ring under the primary note. If it's not a tube issue, there's got to be a component going bad. Did you ask the seller WTF???
 
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