[Amps] step start /triacs/Line Side Regulator

[Wayne Rogers]

David:  I tried this circuit on a large power supply.  The problem with it 
is that it turns the primary on - off on a regular basis.  lots of bang - 
bang - banging of the transformer.  I removed it from the supply.

Wayne N1WR.

Date: Fri, 12 Feb 2010 06:55:09 -0500
From: "David C. Hallam" <dhallam at rapidsys.com>
Subject: Re: [Amps] step start /triacs/Line Side Regulator
To: Jim Thomson <Jim.thom at telus.net>
Cc: amps at contesting.com
Message-ID: <4B75419D.9060004 at rapidsys.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

In the October 1987 QST there was a construction article for line side
proportional control regulator for a high voltage power supply.  Its
purpose is to prevent the HV from soaring under idling conditions when
the tube was not drawing current.  The circuit uses a comparator to
sample the HV and turn a triac in the primary of the transformer either
off or on depending up the relationship of the sample to a reference
voltage.

I don't think I have ever seen this circuit implemented in any designs
or any discussion about it.  I am building a new amp and was thinking
about using it.  Is it a good idea or are the draw backs to it?

David
KW4DH