I received Tom’s RA-4 power conditioner two weeks ago and have been totally satisfied with the results. The unit requires 200 hours to burn in. That being said, I noticed wonderful results the moment I plugged it in. It creates an extremely quiet background for my audio research equipment and brought out details in the music that I never knew existed, very exciting. I have tried many other power conditioners and this is the only one that has not sacrificed the sound, it only made it better. Tom suggested auditioning his power cables too. I had Tom send me two of his new Isis power cords. I had such dramatic results after putting in the new pc’s that I immediately called Tom and told him what I was experiencing. First off the sound had more authority throughout the whole range. Symbols had much more texture and realism. Clarity in the bass notes, from the kick drum to the double bass, very clean. Can’t wait for the cords and conditioner to become totally burned in. Needless to say I have gained great respect for Tom Vu and his products. I think he is one of the few guys out there that really understands audiophile’s and there equipment.