[quote author="raysolinski"]I am racking up 6 api 312 cards...3 with 2520's and 3 with Forssell's 992's...I have both power supplies built but my question is simple..can I power both supply boards (one at +/-16 for the 2520's, one at +/-24 for the 992's) with one 25-0-25V 1 amp torroid or will that be too much of a voltage drop for the +/-16 supply? I know the 317/337 regulators CAN do it but is it a good idea (heat!)? This thing will get beastly heavy if I have to stuff 2 power tranny's in there...
Cheers,
Ray[/quote]
I'd feed the +/-16V supply from the +/-24V supply as a preregulator, but feeding the 16V supply from the same source as the 24V part is ok too(YMMV). With a 50V center tapped transformer and allowing 10% line overvoltage, each 317/337 regulator would see about 38V raw DC at its input. From the datasheet, a 317/337 can stand a max.load current of 0.4A for a max.diff.i-o of 40V and up to 1.5A for a diff.i-o of <15V, that's even more than your 2x 0.5A transformer can deliver. Just use a bigger heatsink. (a 22-0-22V transformer would probably be enough for 10% line undervoltage and min. diff. i-o 3V for the regulator to get stable 24VDC)