REDD 47 Psu | Realgearonline

deepdark
Senior Member

Posts: 110

REDD 47 Psu May 8, 2015 13:38:18 GMT -6

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Post by deepdark on May 8, 2015 13:38:18 GMT -6

Hi there

I'm about to build a Redd 47 and was looking at the psu. I first found the JBB design over groupdiy. His is build with a 6X4 and the 2* 0A2 regulators. Really simple and nice. I redraw the psu schematic with diode rectifier and I replace the 2x 0A2 with a zener string. I would like to know if I'm ok, or if I should put another filtering stage. Is the zener strings allright? By the way, I was searching how to evaluate the ripple factor within a solid state rectifier but found nothing really clear about that. I know how to determine it in a tube data sheet with the curves, but i'm not sure with the diode. Thanks

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REDD47 PSU.pdf (100.08 KB)

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svart
RGO Senior Member

Sewer Robot

Posts: 10,437

REDD 47 Psu May 8, 2015 14:13:49 GMT -6 deepdark likes this

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Post by svart on May 8, 2015 14:13:49 GMT -6

I find that it's simply easier to measure the ripple voltage and account for it with additional C. Ripple factor is simply measured as %r=100(Vrms/VDC).

Shunt regulators from zeners don't like to have currents varied by more than a few percent, or else you'll have serious problems with dissipation excursions. Probably not a big deal with a design like this though, probably more of a problem in guitar amps, however you still must be careful to make sure the system current draw doesn't increase and that the zener stays above 10% of it's zener current or else your regulation will fail.

If you're dead set on going with solid-state regulation, I'd look into more of the series-pass MOSFET regulators that some are using. They are a bit more forgiving in most aspects.

However, if you really want to go with the zener-shunt route, I'd string multiple smaller value zeners in series rather than one high power zener.

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deepdark
Senior Member

Posts: 110

REDD 47 Psu May 8, 2015 16:28:39 GMT -6 via mobile

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Post by deepdark on May 8, 2015 16:28:39 GMT -6

Thanks svart. The svhematic from which i dérives mine uses a 6x4 rectifier 2x 0A2 tube regulator. Some people claim thé 0a2 are noisy and replaced it with a zener string like m'y schematic. Si my principal concern was to know if i did dit right and the psu looks right. Maybe i'll jeep thé oa2, though. Does m'y svhematic looks Good or do i made mistake ?

"I'm givin' you that money so I don't have to kill your ass."