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RE: LC filters for B+ ...

"Spike reduction at the rectifier output only needs a small,
super-low DCR choke with a high-fidelity bandwidth."

A small hash choke will reduce the spikes but what you really want is to remove them altogether. Anything short of critical inductance in the input choke will not keep the diodes on (each in turn) for their full half cycle and that will cause spikes.

With a critical inductance input choke each diode stays on for its entire half cycle and there is no current spike and the currents in the PS stay smooth and sinusoidal. Those currents only reach a level a little over the load current. The current from the power transformer flow constantly to the filter.

With something less than critical inductance in the first choke the diodes still spend a lot of time off and there are periods of time when no current flows from the power transformer to the filter. Periods of time when both diodes are off at the same time. A hash choke reduces this time (compared to a cap input filter without a hash choke) when both diodes are off at the same time but it does not eliminate it and therefore your power supply filter is not (by definition) a "choke input" filter.

A cap input filter with a hash choke added is better than a cap input filter without a hash choke but it's still a cap input filter. Please stop calling it a choke input filter.

Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"


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