Re: Power Supply Filtering: Is More Better ?


"Stephen Cowell" <scowell@xxxxxxxxxxxxx> wrote in message
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<Chief_Billy@xxxxxxxxxxx> wrote in message
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Harrison Ford Prefect wrote:

...

The big win for tightening up is on the output plate[s],
esp. in Class AB push-pull, with some help on the screen.

Sorry, but that last sentence throws me...can you elaborate ?
Do you mean increasing the B+ and screen-grid feed caps
would yield greater results ?

An unfiltered FW supply averages .707 of the peak voltage...

RMS..


add a filter cap and the voltage soars up to the peak.

Well, higher than RMS anyway...


Start
pulling current and the voltage goes down...

You can see this when reducing negative bias, drawing more quiescent current
through power tubes.. Plate voltage will rise with more negative bias.

the more energy
stored in the filters, the more time you have near peak voltage
to respond to big transients. This may or may not be musical...
too stiff a PS is bad, as well as too saggy; one of the design
choices an amp engineer has to make.

Agreed...thanks >


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