> >I'm in the process of assembling my 410 and am wondering about the >optional 100k resistor at R68.
Imho, it's a no brainer. Add the resistor so you can use it with other modules. Without the resistor you still won't be able to use it with a guitar or mic without a pre-amp, and the the notion that "signals in a studio" are only 1Vp-p doesn't have much basis in reality. I added the resistor to my 410, and it works fine with all of my studio gear.