[Amps] RCA 8122 Tubes

[R L Measures]

On Jun 23, 2006, at 3:49 PM, m.ford wrote:

>
> ----- Original Message ----- From: "R L Measures" <r at somis.org>
> To: "Glenn McNeil" <vk4tzl at bigpond.net.au>
> Cc: <amps at contesting.com>
> Sent: Thursday, June 08, 2006 9:09 AM
> Subject: Re: [Amps] RCA 8122 Tubes
>
>
>> On Jun 8, 2006, at 1:55 AM, Glenn McNeil wrote:
>>> Hello Gang,
>>>
>>> I've just been given a pair of RCA 8122 Tubes...never used,  
>>> still  in the
>>> original boxes. Date code 69-04.
>>>
>>> What are the chances they are still OK for use ?
>> Very good if the Al-Ox ceramic has a purplish color from added   
>> manganese.    A high-potential tester will give the answer is   
>> seconds.  With 5kV between the anode and screen, there should be  
>> less  than 5uA of leakage.  i would not uses these tubes in a  
>> unmodified  NCL-2000.
>
> The best modification for the NCL-2000 is to change the way the  
> operator abuses it.
> Keep the meter in screen current and watch it all the time. I'll  
> bet it was all the gg guys that got
> caught looking at the grid current that gave the amp a bad name.

Not using the Eimac-recommended current-limiting screen shunt  
regulator circuit for small tetrodes gave the NCL-2000 its reputation.
>
> Mike  k1ern
>
>
>
>>>
>>> Any ideas
>>>
>>> 73
>>>
>>> Glenn
>>> VK4TZL
>>>
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>>>
>> R L MEASURES, AG6K. 805-386-3734
>> r at somis.org
>> _______________________________________________
>
>

R L MEASURES, AG6K. 805-386-3734
r at somis.org