Depends what you want to do. Do you want to use 3.5mm leads as molex-extensions or something? We need a little clarification.
I don't think you're looking at a 3.5mm plug then...at min. they will have three connections, a left channel, a right channel, and a ground. I think you're actually looking for a power connector, something like this:
Well, I'm trying to figure out how to do something like the junction boxes in Orac3. I want to be able to extend the power from a molex connector (not by extending it via soldering) using one of those plugs
You just match colors to the tip, ring, and sleeve on the 3.5mm pieces - use the sleeve (backmost part) for ground. You can double-up the black wires, as they go to exactly the same giant hunk of solder within the PSU. However, I spoke with G-gnome about this years ago and he told me in no uncertain terms that he'd use standard DC sockets (like above) if he were to do it again, for safety and reliability purposes. Remember, audio jacks are only designed to handle enough current to carry a signal, whereas the DC jacks are actually rated for powering devices.
Indeed. Do note, however, that the way you wire things up somewhat depends on how you intend to use it. With DC sockets, you always have the outer side as the ground connection and the inner as your voltage line, but of course they're also only designed to carry one line at a time - in order to extend a molex (as compared to just powering on a case fan or something, which only uses the 12v line), you'd need a pair. This was part of the reason that G-gnome went with the audio connections IIRC, though with the exception of the optical drives, most if not all of the other components only needed a single power feed and not both sides of the molex. As a matter of best practice if you use the standard DC jacks, I'd strongly suggest using two different sizes for the 12v/G and 5v/G sets, that way you make sure you'll never accidentally fry something by plugging a 5v device into a 12v socket. If you do decide to forge ahead with stereo audio cables, have the back of the socket/jack (the "sleeve") as ground and be consistent in wiring the 12/5v lines to the tip and ring (I'd put 12v at the tip, that way if a connection slips you under-power something by accident rather than over-powering it). Obviously never plug or unplug things while the system is running - this is twice as important with the audio connectors as they're not designed in a way that prevents momentary shorts. Quite a mouthful, I realize. To answer the original question - the physical work on those things is pretty easy, albeit tedious (if you don't have a Helping Hands tool or something similar, I'd strongly suggest grabbing one). There are little loops that you run the wire through, just twist your wire on and solder away.
A standard audio jack plug would be highly dangerous with molex power to it, if the tip touches the case (or any other earthed metal) there'll be an almighty bang. For power over an amp or two you need Neutrik XLR connectors or better.
This thread has been quite an interesting read... In my first every modding project (at age 14 , and no doubt, inspired by Orac3) I used a few 6.35mm stereo connectors (the old school, chunky headphone style ones...what? they were lying around in the garage...), in a port for all my fans to be connected to. It worked quite well (no thanks to my shoddy soldering ) though at the time, I did recognise the emminent danger of having both 12V and GND connections within a finger's distance of one another... cpemma's XLR connectors definitely look to be up to the job though. Have you specified Neutrik for a reason, or is it just a brand you would recommend? I found this on Maplin, and it looks to be up to the job... there is a 4 pin one, which I would buy, but the specs aren't on the page - so I'm assuming they are the same as the 3 pin model... MGT
and on that subject on maplin for them connectors modgodtanvir rapid have them even cheapr as low as £1 each http://www.rapidonline.com/Cables-C.../3-pole-Microphone-XLR-socket-and-plugs/72487