Snake Mod

I have a 50' snake I plan to run from control to booth. Here is the cover:

As you can see it has 6 TS jacks. 4 of those are dedicated to speakers. 2 simply say "M." The speaker wire in the snake is much heavier gauge as seen here:

The "M" inputs which use lighter gauge are wired up in the center and each speaker pair is wired together to have the same signal:

Here's what I would like to do... I would like to disconnect the internal wiring to the center two TS connections. I want to use those two jacks as instrument sends (guitar) to a nearby amp. That give me two spare wires in the snake. I want to use those two wires to convert the Speaker 1 & 2 jacks from TS to TRS with the aim of using all four of them as headphone jacks connected to a headphone amp in the control room? Of course I will have to rewire the ends as well. Will this work? If so, should I use the light gauge wire as the tip, ring or sleeve of the TRS jacks I put in as replacements? Any help appreciated!

the TRS really requires that the pairs (threes?) are twisted to ensure proper shielding, so having the TRS split across two sets of wires will probably not behave as expected. that said, you could try it and see if it works...

This most likely won't work. Speaker cable has a different impedance than guitar cable, so you'll likely pick up some hum. Second, the speaker cables there, appear to be unbalanced (2 wires). To run a TRS balanced signal, you need it to be a 2 conductor + shield.