[Amps] power supply for larger solid-state amps

[TexasRF@aol.com]

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 at 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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