power output levels are similar to the Gilmore Lite. around 15Vpp, 150mA discrete buffer. so it will definitely power the K1000 better than the regular Pico, which is limited to 8Vpp output. but, it's still a portable amp. the goal was to make the smallest 2x9V amp. "hard to drive" is more in the context of portable use, so think like Senn HD800, AKG K701