Re: VTTC question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: robert heidlebaugh <rheidlebaugh@xxxxxxxxxxxxxx>

Matt: Everry time I change tubes in  my VTTC I must re tune the feedback
and the the bias level
        Robert   H
--


> From: "Tesla list" <tesla@xxxxxxxxxx>
> Date: Thu, 14 Jul 2005 11:20:11 -0600
> To: tesla@xxxxxxxxxx
> Subject: Re: VTTC question
> Resent-From: tesla@xxxxxxxxxx
> Resent-Date: Thu, 14 Jul 2005 11:26:45 -0600 (MDT)
>
> Original poster: FutureT@xxxxxxx
>
> In a message dated 7/13/05 8:20:33 PM Eastern Daylight Time,
> tesla@xxxxxxxxxx writes:
>
>
>> Hi all,
>>
>> I have a VTTC in which I am using a GU-81M pentode. I figured since I only
>> have one I should get a backup tube just in case. So I found another GU-81M
>> on ebay and it was supposidly new, so I bought it. Tonight when I went to
>> try it out on the coil there is no breakout and a very little spark when I
>> touch a screwdriver to it. My question is: could the tube have slightly
>> different ratings so that tuning the coil would correct the 
problem or is my
>> new tube actually used and at the end of its life?
>>
>
>
> Matt,
>
> my guess is the new tube is defective in some way.  either
> worn out or just defective.  generally the ratings should be
> very close in the tubes I work with.  I would doubt the tube
> you mention wuold have such sloppy specs, but who knows?
>
> John
>
>