I first did this almost by accident about seven years ago. I had just finished wiring up a buffer and I wanted to hear how it sounded. To make a quick and dirty connection I soldered in a piece of Belden 1701A in, which is a siamesed bonded twisted pair of teflon insulated 24 ga. wires. Well I made the connection using about six inches of wire and the preamp didn't sound bad but it did seem a little short on dynamics and space. I subsequently wired in the selector switch and used 12ga. on one set of inputs and the aforementioned 24ga wire on the another set of inputs and there was no doubt about which type of wire was better sounding.
The inputs with the 12 ga. wire were more dynamic sounding and the bass was much more present and well defined. The sound-staging differences were quite startling. the 12ga. had a larger presentation of the acoustic space where the recording was done and the preamp sounded much more open. Image height,width and depth were also greatly improved over the 24ga..
With these results,I proceeded wire up the rest of the inputs with 12ga.wire,it really was a no brainer. The 12 gauge wire has been used as a twisted pair with the ground leg attached at ground on the RCA jack the other end left unattached. Only the signal hot hits the selector switch. The twisted pair configuration was used to try to add a little bit of capacitance per ft. to the wire. This really was unnecessary as it turns out and just added misery to the wiring job.
Here is a picture of the completed project.
Scotty