[Amps] Squirrely 30L-1

[Jerry Kaidor]

> The first sensible step would be to measure the parasitic resistor values.

*** That would be hard.  I would have to unsolder the coils around them. 
And I'm not convinced that the squirrely-ness is an actual VHF parasitic.
I do have a spectrum analyzer good to 450MHz - wouldn't be too hard to
set up some sort of voltage probe thingie to sniff the output ( without
actually connecting to it ).

   What I *might* do is verify the grid resistors and caps, make sure that
the grids really are well grounded.  I can measure the reactance to
ground with my MFJ259B.  And look for RF ground loops from aged
metal-metal connections.

> The second thing would be to accept that Chinese 811A's will never be
> completely stable on 10-15M

*** I wonder why?  Does that caveat extend to Chinese 572B's ( Taylor et
al )?   I might stick some American tubes in it this afternoon and see
what
happens.  And if the Chinese 572B's are not good, I might need to cancel
my order with RF Parts.

>
> The third would be the ability to understand that 2dB additional NF on
> 10-15M might only make a difference
*** This is certainly true :).

                      - Jerry Kaidor