PC Power Supply for DIY - Don't try this!

[Tony Clark]

> One way to use such supplies to get proper power at say +/- 12V would
> be to use 2 PSUs and hooking the +12V of one of the to the ground of
> the other. Then would the ground of the other be -12V... but this is
> potentially very dangerous cause you migth have a low-ohmic contact
> between ground and case which would then cause a short of the low PSU.
> I would not recommend such a interconnection unless it has been
> verified that the output sections is really floating to the case (and
> other potential shortage points). Recall also that the +5V leads of
> the lower PSU will get the -7V potential and how the current of that
> cursuit will flow is a diffrent story...

   Yes, definately do NOT hook up two switching supplies in that manner!  
You can only do this with "floating" power supplies like those old 
Heathkit variable power supply jobs (which WON'T run an ASM-1 board worth 
a flip).  I'm not even sure I'd try this with newer linears.  I'm just 
very cautious when it comes to plugging in my synth circuits!  Nothing 
would ruin my day more than to fry a whole board because of power supply 
screw ups!

> Maybe traditional PSUs isn't to bad after all... :)

   That's why they still make 'em.  :)

   Tony

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I can't drive (my Moog) 55!
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Tony Clark -- clark at andrews.edu 
http://www.andrews.edu/~clark
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