Power Supply TO220 vs TO3?

[tomg]

Dave!....18 modules on TO220s No No No! 1 Amp might be enough
but the regulators will be red hot...... TO3s would be better but by the
time you buy parts for a new supply you could have a surplus Power One 
+/- 12 2-5A linear supply...I have seen them for as little as $20.00 but
twice that much is still a deal if you modular. 

An alternate approach is to put TO220s on every module (or so) and 
connect them all to a common unregulated supply thats capable of a 
few amps. Say +/- 24V at 2A. I actually like this better than a central
linear supply but in the end it costs more.

Tom


> Design and planning continues for my modular (mostly based on EFM's stuff).
> 
> An engineer friend dropped by and said my +/-12v PS design would simply 
> catch fire because I'd used TO220 7812 & 7912 regulators instead of going 
> with TO3 packages.
> 
> Should I be concerned?  What would the expected current draw be from (let's 
> say) 18 modules of the VCA5b and deg2a sort?  Can I get away with TO220's or 
> do I need to do a (third) redesign using TO3's?
> 
> dave