I'll be getting a modded HE-6 this week (LFF Code-6), this is going to be fun. The only other amp I've used the HE-6 with is the GS-X Mk2 though that was a stock HE-6, and the combo was great. - EDIT: The amp seems to drive the HE-6 fine as expected. I typically have the volume at about 2 o'clock. The detail retrieval, imaging, and mids are spectacular with this setup. Treble is not forward at all and mostly pretty clear but with some flaws (this is the Code-6, one of the mod's main goals was to tame the treble).