----- Original Message -----
From: Steve Katz <stevek@jmr.com>
To: 'Rich' <2@vc.net>; Alan Ibbetson <g3xaq@hotmail.com>; AMPS
<amps@contesting.com>
Sent: 14 October 2002 22:46
Subject: RE: [Amps] How light can you make a 500W amplifier?
> I don't believe a 1 kg power supply using a 6x multiplier at 50 Hz or 60
Hz
> is possible, at the current level required. Unless someone invents
nearly
> zero-mass large-value capacitors required by the multiplier, seems to me
a
> 6x multiplier at any current level beyond a few mA is an inefficient
power
> conversion method at 60 Hz line frequencies.
Many years ago there was a design in a UK magazine using 3 x 4CX250s with
voltage quadrupling off 240V mains - arranged to give +/- 700V so as to
minimise the voltage offset to ground. I'd have to dig for it but I think
it
met the designer's aim of 400W out on all bands.
Apart from the weight problem with heatsinking, I'd look hard at solid
state - poor IMD mentioned earlier is not inevitable, and can result from
poor design and/or pushing the devices too hard. It's exactly the same with
tubes.
Steve
>
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