Posted by PakProtector [ 64.12.117.9 ] on November 07, 2007 at 19:46:58:

In Reply to: Re: questions re 300b group build posted by stewcle on November 05, 2007 at 16:50:41:

hey-hey!!!,
PSRR of a pentode depends upon what sort of output you're dealing with. In this case it has terrible PSRR, because of the high plate impedance( the plate curves are nearly horizontal). What ever voltage shows up at the top of the plate load resistor, shows up at the plate end too. Now if we were transformer coupled, that behaviour is a plus, because the voltage would not be able to induce a current and w/o current change in the output TX, there is no signal.

IOW, you'll need a clean DC supply for the driver pentode.
Best Regards,
Douglas

Replies: