alright fellow, heres the deal..
to TURN YOUR HEADUNIT ON you need to hook one of the YELLOW WIRES out of the molex connector to the RED AND YELLOW wires on the headunits harness, and you need to hook the black wire to the black wire in the molex next to the yellow wire.
to turn the powersupply ON whilst its NOT inside a PC *assuming you are using an ATX unit* you need to take LARGE 20 pin molex connector, and find the GREEN WIRE, and cut a short piece of wire and jump it to a BLACK wire.
*the black parts on that molex are burned because thtat power supply i was using for the picture totally just blew up. it was in my brothers computer and it was lying around. they do die sometimes //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif*
as far as noise? i didnt expierence any, but im sure if you hooked it up to a computer you might - but dont recommend grounding to somthing that is NOT in loop with the powersupply... since the powersupply is grounded to your house, you can ground it to a cold water pipe i suppose. but thats pretty retarded if it works while being grounded to the unit //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
so try that first.
if you want to make a DEDICATED powersupply for amplifers\and all that other happy shit...
i suppose i can write up a tutorial because i plan on making another one... fact is - i tried to make one out of that broken powersupply because it looked like only its 5v rails were busted and ya dont need them anyway - i got it all done and the sucker popped in 5 seconds lol.
but thats really all ya need to power it up. i just had a fan lyin around that used a male molex with 12v\gnd lines out of it, and pluged them inot the wire harness with some wire nuts, and then plugged the molex into the powersupply that i bridged.
also - think of that green wire as the 'remote turnon' for an amp. basically when its pluged into the motherboard, the motherboard jumps the green wire to a ground - and when the powersupply see's 'ground' on that green wire - it allows itself to turn on.
just thought id mention that. so good luck mang.