Thanks, Jason. So how loud do the rs2s get, with the 901? Nice works guys for putting aside a day to run this gear and post the helpful info.
the grace will easily drive the headphones loud enough to kill your hearing. seriously. I usually listen with the grace at 1/4 of it's max volume, and it's plenty. the thing is, the headphones are so detailed, you don't have to listen loudly to hear everything, as long as you're in a quiet environment. The grado's are all open design, so they provide no isolation from the outside.