02-08-2015, 11:30 PM
(02-08-2015, 10:06 PM)morzh Wrote: Well...it works well, other than at the very maximum of volume it oscillates.
Not unusual for a TRF though in tethrodes Miller effect is not as pronounced....
Maybe I should put it to rest now.
When at Kirk's will solder the cord to it.
Mike;
I think that oscillation is in part due to the audio output stage, I've noticed that sets with push pull #45s do it as well, I think it's just the inherent instability one gets from triodes, which was why they developed screen grids, pentodes, and then beam power types. This Jackson Bell was what they called a "Midget Set" back in it's day, it was intended to be a lower cost, mass market set, not unlike a Philco 20 but obviously cruder. I would like to get my Philco 96 going just to compare, it has a proper AGC circuit rather then a funky control attempting to vary the cathode bias and antenna input in the front end.
Regards
Arran