DC Throttle Recommendations

[peteski]

peteski;
Those 12v supplies piggybacked are not "old school" if that is what you were referring to. Both are switching supplies. 

OK, thanks. I based my commend on Max's comment.  So the fan is not really required.

[mmagliaro]

I don't see how the switching supplies have anything to do with the throttle board's full wave bridge and regulator.
The bridge will pass the full current through two diodes, so at 3A, you have 1.4 x 3 = 4.2 watts, which will make it really
hot with no heat sink.  It will probably not get above the temp it can survive, but hot. I know with the bridges I am testing right
now, that exact combination gets it up to about 75 C and that's WITH a heat sink.  Without the heat sink, it will easily go over 100 C.