I use this as my primary 2 music system. Have not experimented with SETs yet. Amps run in triode mode at 60W a piece. Have plans to add Ultra platforms under all components with the exception of speakers and crossovers. Tungsten grade 3 balls sourced from third party supplier at $60/per intead of $115/per from symposium. Very open, natural sound. Incredible soundstage and imaging - no fatigue at all with 6550s in amplifiers.