Yo TED--why is my DSD so responsive to power cables?

Audio Components DACs
22

Something different, getting a great power factor (> 0.94) is a good first step: you can’t simply top off your caps (which shaves off the top of the AC waveform.)

If you can arrange that you draw down the caps quite a bit and then charge them slowly as the AC rises and also as it falls you can get a better power factor. You can further lessen the draw at the peak by adding a “soft” voltage doubler in parallel to provide power at the peaks and when the voltage crosses zero (well there’s a full fullwave rectifier there, but you get the idea.)

There’s no free lunch: as the power factor gets better the regulation suffers at the top level supply: taking longer to empty the caps means the voltage falls more but you are drawing current to refill them over that longer time. You couldn’t do it this way in a power amp.

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23

Very cool, Ted

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24

I think that many people use too big of a filtering cap just after the bridge rectifier: the bigger the cap the better the regulation, but the shorter time used to fill it. The smaller the cap the worse the regulation (at that cap) but the longer the fill time. You can regulate better after that. I used a smaller capacitance first cap (well really, caps in parallel to increase the current handling capability) on my original prototype. The TSS does things a little differently but still gets a similar (and larger) effect.

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