Another 'custom cable' question!
My band is on wired in-ear monitors, and we're working on improving our cabling system. I'd like to build a few custom hybrid cables that combine a 1/4" T/S instrument cable with a stereo Headphone extension cable. Our Headphone amps are Behriner P1 and live on our pedalboards. At the moment we loom an instrument cable with an off-the shelf headphone extension, but while it's been functionally okay (notwithstanding one player's defective headphone extension), it's a bit messy. The one off-the-shelf guitar+headphone cable I found in an earlier search got bad reviews for reliability...
My question is what raw cable stock to use. I initially figured standard star quad mic cable would do, but am now concerned that cross-talk between the headphone signal and the high-Z unbalanced instrument signal would be problematic. So, now looking at two-pair cables with separate shields, such as this Gepco 6600:
http://www.gepco.com/products/proav_cable/analog_audio/singdual_2prshielded_M.htm?v=1I assume that wiring both conductors of one pair to the tip of the T/S instrument line will be functionally equivalent to a standard unbalanced coaxial instrument cable; is this a fair assumption for a ~15' run? One member plays sax with a bell mic, so I could use this same cable for him, with one pair as a plain ol' mic cable and the other as his headphone return.
Is there some other bulk cable stock you'd recommend for this purpose? Any 'gotchas' I may be overlooking?
Thanks as always!