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From: dje@datacube.UUCP
Newsgroups: sci.electronics
Subject: Re: high voltage Power Supplies
Message-ID: <100500016@datacube>
Date: Tue, 14-Jul-87 11:08:00 EDT
Article-I.D.: datacube.100500016
Posted: Tue Jul 14 11:08:00 1987
Date-Received: Fri, 17-Jul-87 04:49:07 EDT
References: <1811@ttrdc.UUCP>
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Nf-ID: #R:ttrdc.UUCP:-181100:datacube:100500016:000:1474
Nf-From: datacube.UUCP!dje    Jul 14 11:08:00 1987


The  cleanest,  lowest  noise  power  supplies  are linear regulated.
Switchers are *mostly* for high  power applications  since their main
asset is efficiency.   Their  other assets  are light  weight and the
ability to convert DC to DC.  If you want DC to  DC conversion that's
clean, one possibility is a switcher followed by a linear supply.  

I missed the original posting, but I heard  a few  references to tube
type preamps.  That means relatively low power and  I assume throwing
efficiency and weight to the wind.   If I  was building  one, I would
use a standard  60 Hz  power transformer  followed by  either tube or
silicon diodes and a reasonable amount of filtering.  Then a tube for
a  series  pass regulator  (cathode follower  configuration) or maybe
even a high voltage amplifier transistor.  

Tubes  as  diodes  have  more  inherent resistance  than silicon thus
causing  lower  charging  currents and  lower 120Hz  harmonics on the
power supply.  The linear stage then has an easier job.  

Tubes as  high voltage  series pass  elements take  abuse better than
transistors.  If  you're really  into nostalgia,  use an  0A2 (or the
like) as the power supply reference. They have a great glow.

 				Dave Erickson
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