VF14, how to test?

[Apache5]

hi i have a VF14 tube (M kind) and want to know if its suitable for an U47 mic. I'm not still sure about to build a mic or sell it but first I need to know if its functional and if it can sound fine in a mic. For what I find searching info it seems that it must be tested on a real U47 to really know if its suitable for the job... but I have not an U47 to test it. What can I do? Is there another test that I can do? I think not but...

Thanks

 

[gyraf]

In my opinion you need to hear the tube in-circuit (and over some time, e.g. 24h) in order to evaluate if it's good or not.

Simple emission testing and that sort of measurements tells us little about how it will behave in "real life"

Jakob E.

 

[Rossi]

You have to test it in a U47. A tube tester won't tell you anything about noise for instance. Also, you have to be aware that the VF14 - like most tubes in a microphone - is used out of spec. Which means you have to test it in this special out-of-spec application.

If it works well, it's probably saner to sell it. Because if you build a mic around it, you'll be in the same position as a U47 owner: fear of tube failure. I have a U47, and often enough I use a different microphone, just so I don't use up the tube for everyday crap.

 

[Apache5]

Thanks for your replies... these was what I was thinking too :-[  . I must test it on a u47... The problem is to find someone willing to test it in a u47. And yes, you're probably right that it would be wiser to sell it... seeing the other parts needed and what it would cost me to get them I would have to stop doing many other projects in order to afford it

Thanks again!

Arnau