I agree with Alex,
I haven't done it, but it should be possible. Simply build the amp in a
similar way as the switcher in a smps is built. Isolate the input and output
of the power transistors and float or ground the mains.
Affix a note inside the amp saying the case and certain parts of the interior
of the amp may be above ground and potentially at the mains voltage.
I looked at the same idea with the Microsemi parts a few years ago and thought
it would be very possible.
Paul,
KG7HF
Date: Mon, 16 Sep 2013 13:13:23 +0300
From: "Alex Eban" <alexeban@gmail.com>
To: "'Leigh Turner'" <invertech@frontierisp.net.au>,
<amps@contesting.com>
Subject: Re: [Amps] Direct rectification of AC mains to derive the amp
VDD
supply
Message-ID: <005401ceb2c5$625879b0$27096d10$@com>
Content-Type: text/plain;
charset="US-ASCII"
Why?
The TV industry and the American radio industry has been doing it for tens
of years! You don't have any qualms about using a transformer coupled power
supply, but you shrink when considering a transformer coupled amplifier. all
you have connected to the live mains is a piece of about 6 by 12 inches.
The argument of the existent high voltage is irrelevant, since you have in
any case about 150 volts on the amplifier while here in 4 Zulu land we end
up with about 300 VDC.
All you have to be careful about is to have the chassis connected to the
neutral side of the line during work on the open amplifier!
I'm just planning one of these right now: 2 ARF1501 in push pull. The nice
thing is that the output impedance at 300V is quite close to 50 ohms! So,
all you need there is a 1 to 1 balun.
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