I would like to buy a g natural but I want to be sure that I won't loose the balanced signal coming out from my 814ce Taylor guitar when plugging it into the G Natural with Trs-Trs cable.
In fact, I want to be sure that the instrument input is really balanced.
The Mic input and the Line input are balanced - but not the instrument input - The outputs are balanced. If you want to keep it balanced, use either the Mic input or the line input.
If the level of your guitar is too low for the line input or if the Mic input is distorting, you can still use a balanced to unbalanced cable to the instrument input. (connect pin 1 and 3 on the G-Natural side).