10-10-2021, 05:31 PM
(10-10-2021, 08:51 AM)Kalee20 Wrote: One Qu: running the output valve without bias, and setting anode current by Vg2 gets you where you want to be. But does this allow sufficient headroom for the AG swing on g1 without running into grid current? Could you cope with stronger signals with a bit of -ve bias, and higher Vg2?
At low levels grid current seems to me to only really be an issue with distortion or less predictability in results. Don't forget that transmitting valves are often intended to be run into grid current, the level being metered to check (Ok they are designed for it and usually power valves and RF). With a rod electrode, as previously comments, there is perhaps less likelihood of problems. Maybe the limitation is really just overall cathode current?
I have an article on one particular Russian radio (R-326) which used a 1j29b input to 1j24b then 1j37b mixer was with signal level. The suggestion is that a large antenna results in blocking. Perhaps not particularly a problem with the sparsly populated bands these days. I have never seen any details with these valves though. Interestingly, when I look at the Russian manual I have for it, valve voltages are listed. They are pretty much as may be expected but maybe I'll look a little deeper.
Tracy
