Very versitle for the headphone/speaker thing but also the on the fly Ultralinear and Triode switch. It was on the warm side and in my opinion a little lacking in dynamics too. Per Dennis Had (Sp?), AMB changed a resistor that added more voltage to one of the signal tubes, don't remember which one, and then also used some SP Slam Adapters for using 5687s for the 6SN7s. These changes all helped but never got me satisfied. Headphone jack was just OK, not bad but nothing really special either.