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RE: What size choke are you .. .

Posted by Tre' on May 15, 2023 at 13:18:05:
The input choke is 70mH. Critical inductance with the load the 300b filament is drawing (1.2 amps) is only 11mH

Choke value in Henrys = ((voltage/current) + dcr of choke)/1000

FYI Critical inductance is the amount of inductance that it takes, for a particular circuit, to keep the diodes on, each in turn, for their entire half cycle. That keeps the charging currents to the first cap (and the load) just a little bit higher than the load current. With a cap input filter the charging currents can be many many times the load current because the diodes are only on for a short time and those current spikes cause (according to Lynn Olson) RF to be generated and then it's just everywhere. You can't filter is out, you have to try to shield it.

Tre'