When I lived in a part of L.A. where a good deal of the movie studios were located, I had maybe three or four nearby retail outlets where I could buy the tubes I required to power my stereo. This was especially important during the days of my 8417 equipped Quicksilver Mono Amps which, for whatever reason, regularly ate tubes and spat 'em out. The tube nightmare came to an end, though, when I bought my 6550 powered Primaluna. Ninety percent of the sound. Five percent of the aggravation.