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Ray, the whole point of using a choke input filter...

...will be lost if there is no choke.

And this point is that a PROPER choke input filter doesn't take pulses from the AC line at the peak of the waveform, but takes an almost a pure AC signal - hence the AC wiring, transformer, diodes and assocciated circuitry don't splash intense pulses of RF around the inside of the amp at 100 or 120Hz and all harmonics up to daylight!

A following regulator will/should kill the B+ ripple for certain, but so what if the sensitive input circuitry is being bathed in wideband pulsed RF?

A second point is that these pulses are present in the powertransformer's magnetic field - and therefore appear on the heater lines, and on any other voltage made from the same transformer that is driving a cap input filter!

The same thing happens with a cap input DC heater supply for a preamp/phono stage - this can make HUGE pulses which lay themselves over the B+, even if that's using a choke input filter.

Personal experience...not just theory!

Regards, Allen

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