OK, while on a rant,? (and misplacing my PSUD-3..........'wish list' from years ago)? ? I just remembered? a useful item that would be? an excellent addition to PSUD-3.?
And that's the option of using a resonant? choke filter.? ?On any resonant choke filter, the choke is right after the FWB assy, followed by the usual filter cap.? ?A? 2nd cap is wired directly in parallel? with the choke.?
The choke plus the cap across it, parallel resonates at the ripple freq (120 hz, or? 2F if using 60 hz power).? ?100 hz, or 2F if using 50 hz power.? ?That filter config works superb for a lot of applications, like tightly regulated screen supplies.? ?Collins used a resonant choke setup for both the B+ supply...and the? screen supply in it's 30-S1 linear amplifier.? ?Henry radio also used the resonant choke setup? for it's? B+ supplies.? The resonant choke forms a notch filter at 120 hz (2F).?
On some smaller 5 kw, single phase FM broadcast B+ supplies, the resonant choke setup was also used....and then followed up with a conventional LC filter. In that case, the resonant choke? forms a notch filter at 120 hz...... but was not enough suppression at harmonics of 120 hz, hence the conventional LC filter? was added? on.?
Dunno if a resonant choke? can be added to PSUD-3? or not.? It would be a nice addition.?
Jim? VE7RF
