VF14 Rejuvenation in U.K.?

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paulcheeba

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Mar 29, 2017
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Hello, is there a tube mic expert in the U.K. who can regenerate a few tubes. Without sending through Brexit etc.
All the best
Paul
 

GeorgeToledo

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Mar 3, 2015
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Regeneration of VF14 isn’t usually about baking them.

The idea of regeneration of a VF14 is based on the tube having been underheated in a U47. The tube is gradually brought up to the original operating values so that any deposits burn off the cathode. I’ve never done it but that’s the basis on which I’ve seen it discussed. Maybe that will help retrieve some of the old internet conversations about it.
 
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GeorgeToledo

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I see some overlap with what I’m describing in the section on cathode poisoning but I sure don’t think that’s the way I’ve heard of it being done with VF14. I think some people just try pushing the heater a bit past U47 spec but even still under the original operating spec.
 

GeorgeToledo

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You might try cleaning the pins of the tube with some caig before getting into anything else, if it is that some sporadic discharge is happening. The contacts in a U47 may need cleaning as well.
 

paulcheeba

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Mar 29, 2017
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It’s weird I’ve been recommended it by 2 German’s called Andreas. I’ve had one done by Herr Grosser and it was still noisy but the signal ratio was improved,
 

gyraf

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Paul,

Can I ask: Do you have a real u47/48 in desperate need for a VF14, or are you looking for turning worn-out tubes into a backup option?

/Jakob E.
 

paulcheeba

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Mar 29, 2017
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I have a couple of U47’s that would benefit from spares, I’m not a huge fan of the Fet or the glass variants. I’d love to get some more life out of these couple of vf14’s
 

TLRT

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I use some vintage testers, I have a modded Neuberger RPM370 where I listen the tube noise thru a transformer balanced output thru the anode, or any other tube source. Never tried with VF14, but used the "cathode burning off" test with EF806s tubes successfully.
 

paulcheeba

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Mar 29, 2017
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I use some vintage testers, I have a modded Neuberger RPM370 where I listen the tube noise thru a transformer balanced output thru the anode, or any other tube source. Never tried with VF14, but used the "cathode burning off" test with EF806s tubes successfully.
Cool, where are you?
 

TLRT

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Jan 9, 2014
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I tried it,works well the neuberger can create heater max 200V, grids -100v and anodes up to 500v. Looks like I have only good vf14's they are not noisy.(sorry guys not selling)
 

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