I realize this is an old thread, but is anyone aware of any companies/individuals making devices like these for sale? I've never soldered anything in my life so it would probably be a waste of time and money for the parts, but I guess if I can't buy them anywhere maybe I'll give it a try.
I picked up a $2.99 5v to 12v converter from China on Ebay, just to see if it could work, but it didn't. It is designed for interfacing solar chargers and probably has a component somewhere that knock out the IR signal.
I'm trying to go from Global Cache (which uses either 5v or 3.3v depending on who you believe) to Speakercraft (which uses Xantech compatible 12v IR) Global Cache sells a cable for $40/ea, which is pretty hefty considering I need six of them.
This device wouldn't exactly fit in a cable, but it sure would be cool if I knew what I was doing and could build six of these on a 3"x12" board with 3.5mm jack inputs and screw terminal outputs. I could box it up and it'd fit perfectly under a stack of GC100s!
If the $40 cables are my only solution, I may end up deciding it doesn't cost all that much more to just buy a new zone preamp that the GC100 would support directly!