Mendota 98: I have the Sennheiser 600's with the upgraded Cardas 10 Ft. cable. I've owned the following headphone amps: Musical Fidelity X-CansV2; Creek OBH-11 AND OBH-11SE, Grado RA-1, Earmax, and Sugden Headmaster. The one I have kept is the Sugden Headmaster, connected to my preamp with Cardas Neutral Reference interconnects. We all have our preferences of course, but I found the Sugden to outperform the others by a fairly wide margin. The Earmax basic version, in my opinion, does a fairly poor job of driving the 600's. If you decide to go Earmax, I'd purchase the Earmax Pro. Good Luck.