Scott,
No, $500 is way over the mark even for a regulated homebrew supply or new.
Forget paying retail for Astron. You have a few options;
(1) By from ebay. I've seen Astron and others sell for well below list on
there. Look at Pyramid or Elenco supplies. Their 50 amp (40 amp continuous) is
just as good in my opinion as I have serviced all including Astron. With
Astron, your buying a name. They all use about the same regulator circuit. You
can buy a new Pyramid 50 amp for about $135 on ebay, used even cheaper. The
three main components in a regulated sypply are the regulator transistors
w/heatsink, the output filter caps, and the transformer. If they're sized
right, it will do what you want.
(2) Construct one yourself using surplus components. Just don't buy any surplus
electrolytic caps that was made in China, Hong Kong, etc from a few years back.
There was an industrial espionage scandal there, and a bunch of bad caps.
Surplus Japanese caps are ok though.
(3) Use a car battery in a well ventilated place. Better yet, use the Yellow
Top gell cell batteries. They hardly release any gas. I forget the name brand
off the battery, but do a search for yellow top batteries. They are gell cell
and use a spiral core. That's what the CB shootout guys are using in paralell
and in home. Just use a charger to keep them charged up. I know one guy who
made a battery shed outside the back of his home shop. He paralelled four
batteries there with a charger and ran welding leads inside. It worked great
with power to spare.
The main thing is to look around on the used and surplus markets and auctions.
Best,
Will
*********** REPLY SEPARATOR ***********
On 1/27/06 at 5:53 PM Scott Townley wrote:
>I would like to use my SGC-500 in the shack from time to time so my
>attention has turned to a suitable power supply.
>This amp runs on 13.8VDC and about 70-80A.
>On the commercial side I suppose I could run a pair of Astron 50 or better
>in parallel but that would set me back >$500.
>Or I could get a deep-cycle battery and float it with a 35A supply but
>that's $200 (this may well be the optimum solution though).
>As it happens I have a 10VAC, 100A transformer (actually it's
>dual-secondary, and each secondary is marked 10V/100A) and a 1F (or
>1,000,000uF) capacitor that the audio nuts use in their cars. So I'm
>thinking I can build it myself...capacitor input filter would be 14.1VDC
>max which is fine for the amp.
>One question is: what to use for rectifiers? It seems that only Schottky
>devices are suitable, since they have the lowest forward voltage
>drop. With a full-wave bridge that's two diode drops right there, I might
>be lucky to get 12VDC out of the whole bit. I can find a few stud-mount
>Schottky devices for not too much money ($20 or so for a whole bridge
>worth), but they will require a bit of heat sinking.
>Any suggestions before I press on? Is 10VAC just too close to the fuzzy
>edge for a 13.8V amplifier? 1F should be enough filter capacitance, is
>there some reason those audio stiffening caps aren't suited for filter
>service? (They don't quote any peak or surge current ratings)
>TIA,
>
>Scott Townley NX7U
>Gilbert, AZ DM43di
>http://members.cox.net/nx7u
>
>
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