I pretty much disagree with Shadorne. Nice system! I owned 150s. It should be in Ultralinear and you should be using KT 88s. Also I found tube bias needed to be adjusted regularly. You could have some dead (or near dead) tubes.
Power cords, interconnects, and speaker cables all make a difference. I really like Morrow Audio MAP2 power cords, Either PS Audio Transcendent silver interconnects or DH Labs Revelation. Get XLR if the preamp has XLR I/Os, if not replace it with a differentially balanced preamp! Ditto the Consonance. The Raysonic 165 is killer and the balanced tube outs are so good you can eliminate the preamp all together! Clear Day solid core silver shotgun speaker cables. If after doing this you still have speaker issues look at Usher, Triangle, Reference 3A...
Power cords, interconnects, and speaker cables all make a difference. I really like Morrow Audio MAP2 power cords, Either PS Audio Transcendent silver interconnects or DH Labs Revelation. Get XLR if the preamp has XLR I/Os, if not replace it with a differentially balanced preamp! Ditto the Consonance. The Raysonic 165 is killer and the balanced tube outs are so good you can eliminate the preamp all together! Clear Day solid core silver shotgun speaker cables. If after doing this you still have speaker issues look at Usher, Triangle, Reference 3A...