I know some one that is going to have Frank build him a DU 550 and being with out an amp for his HT-3s. He could play around with his Hafler DH-200 that is stock, and I have a DH-200 also, but mine has been modded. Some one put two of these big old 25,000uf caps in there and who know what else? It does have a three pron grounded AC power cable, I don't know if this is a mod or stock? What I wanted to do was bridge them with one of Frank's older Fet/Valve bridges. Boy I sure don't want to blow up one of his HT-3s.