[Amps] Direct rectification of AC mains to drive the amp,

[Peter Voelpel]

Yes, transformer less power supplies are great.
I used them extensively with my big sweep tube amps in the seventies.
Those were using all three phases and both polarities with one way
rectification, doubler and tripler circuits, to get a maximum of 1800V out
under full load.
Anode voltages could be switched from 620V to 1860V in 310V steps.
Was big and heavy, but much less weight then with a transformer.
Total amount of capacitors used was 140mF (140000µF).
The output voltage dropped from 930V to 910V for instance when I drew 10A
with the sweep tube tablet and used the -310 and +620V circuitry.

73
Peter



-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Jim Thomson
Sent: Sonntag, 22. September 2013 19:26
To: amps at contesting.com
Subject: [Amps] Direct rectification of AC mains to drive the amp,

Date: Sat, 21 Sep 2013 09:50:52 -0700
From: Don Jones <ko7i at comcast.net>
To: amps at contesting.com
Subject: Re: [Amps] Direct rectification of AC mains to drive the amp,
VDD Supply

This is tricky. If the outlet you are using as the source is not daisy 
chained to a bunch of other outlets and goes directly to the panel, and 
you use a true 3 wire connection L1, L2 (or N) and Gnd, you can "get 
away" with it provided you use an appropriately selected EMC filter too. 
It is safe and efficient? no, heed the advice that you have been given 
by others.
Vy 73, Don KO7i.

##  Why wouldn’t it be efficient ?    With direct rectification you just
eliminated
the xfmr !   Now you have NO limit to the amount of power you can generate.
No V drop across any xfmr either, no sag...no xfmr.  Both static and dynamic
regulation would be
better, a lot better.   No magnetizing current on the primary of the xfmr as
there is no xfmr. 
No heat generated from the xfmr...as there is NO xfmr.   You also just freed
up a ton of
space.  You also eliminated  a ton of weight. 

##  For high power use, Id say it’s the ideal ticket.   All you need is big
ga  CU wire back to the
main 200A panel.   I would not write off a transformerless   supply just
yet.    I think we are just getting
started.   240 x 1.414 =   340 vdc.......and  @  10-100A  CCS easily. 

Jim  VE7RF
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