Perhaps you could find a 12.6vac transformer rated for 8 or 10 amps and
series boost the 120vac enough to overcome the diode voltage drops. The 10v
100A
transformer would need to handle some extra stress at high duty cycle. Your
amplifier is not rated for 100% duty cycle so the transformer might ok.
73,
Gerald K5GW
n a message dated 1/27/2006 6:54:04 P.M. Central Standard Time,
nx7u@arrl.net writes:
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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