well the t50rp's are not that hard to drive in my opinion. i have harder time powering my df's than the fostex on mostly everything even when i use to own an ipod. fostex worked fine with enough volume and i had the enclosure stuffed to hell with fiberglass and polyfill to eliminate resonance completely in the enclosures. i liked the fostex and were very clean sounding but my friend was trying to get hold of one and i already have my df's so i just gave it away since i wouldn't be using it anymore. i did run them off of speaker outputs too when i use to have them but i found gain kinda ridiculous without any -20db button.