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In Reply to: RE: Less Lazy posted by drlowmu on July 20, 2014 at 07:36:58
Higher 'Z' ? I had no idea you could measure impedence on PSUD2 . At what frequency was this measurement taken ? ...and what was the actual impedence ?Al
Edits: 07/20/14Follow Ups:
Hi Al,Follow this. In the top simulation, the voltage dropped on the current step, from about 286.88 VDC to a settled VDC of about 283.00, a 3.88 VDC drop.
In the bottom simulation, the voltage dropped on the current step from about 344.70 to about 334.01 VDC, a 10.69 VDC drop.
In each case, the current change was 14 mA. or .014 A.
Ohms Law, Voltage over current equals resistance.
3.88 VDC divided by .014 A. is 277 Ohms.
10.69 VDC divided by .014 A. is 763 Ohms.
277 Ohms versus 763 Ohms. This math, Ohm's Law, can be applied to any current step in PSUD2.
Are we two now on the same page ? Hope so.
One other point I'd like to make. Over the last couple of years, I have changed my priorities on Power Supplies and PSUD2. I no longer believe that the "lowest Z" is the best sounding supply. If that were the case, everything I built would have a solid state rectifier, yet I LIKE the sound of directly heated vacuum tube rectifiers over Crees, etc. and I will use vacuum rectifiers with no cathodes, despite their higher Z. I prefer the sound of ONE dual rectifier tube, and will not parallel tubes in my DC circuits any more. I also have greatly relaxed my desire for the fastest settling supply, like under 50 mS as per John Swenson. This under 50 mS comes at a price, of an overshooting, sometimes ragged step response. In 2014, I look to have a SMOOTH step response as one of several simultaneously combined priorites, so I have veered from the writings of Hasquin and Swenson, and am pleased to do things now as "I" like to do them, despite "theory ". Dealer's choice !! Live, listen and learn.
Regards,
Jeff Medwin
Edits: 07/20/14 07/20/14 07/20/14
That is not impedence . What you describe is a phenomenon unique to PSUD , it does not happen in a real amplifier . You are describing the settling time of the simulation .
I don't see Hasquin or Swenson here much any more . I think you've scared them off ;)
Al
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