[ARC5] Quick sensistivity comparison

[Geoff]

> On 13 Jun 2013 at 4:45, J. Forster wrote:
>
>> Ken,
>>
>> It might be worth checking for gas in the tubes.
>
> In which? Do you mean the 12SK7s? Or in all?
>
>> I'd suggest running them for several days at nominal filament, nominal
>> plate, and biased to conduct about 10-20% of rated plate current to
>> allow the getter to clean up anything that has diffused into the tubes
>> in the last 70-odd years.
>
> OK. I can do that easily enough.
>
>> After that, try the NF test again.
>
> OK. Will do, John. Thanks very much for the suggestions.
>
>> YMMV,
>
> Yes! Won't it just! :-)
>
> Ken W7EKB


A gassy tube will drive the grid more positive and increasing its gain and 
at some point exceed dissipation ratings.

Carl