I just installed a pair of Amperex 7308 tubes in my Pathos Classic One. There was a noticiable improvement in bass response and openess. However the most stunning upgrade that has affected the Pathos Amp. was installing a Richard Gray power supply. Particularly the 600s. Before this effort I was ready to get rid of this amp it had no life and no dynamics. A beauty with no personality. When I played the first song after plugging my equipment into this power supply my jaw literally dropped. I had to take back all the negative things I said about Sam Tellig of sterophile. Hope this is usefull.
