@ charles1dad, Hi, Did you see how many tubes the m-1 has?, If its as clear sounding as it is made out to be, I would not want to go thru the exspense of tube rolling all those tubes, LOL!, for what reason would I do that if the preamp has the spookey clarity its claimed to have?, dude, thats a boat load of funds to tube roll this baby to the quality tubes of my choice if it was needed?, I had a tube source componet that was an ayon one time, and the tube choice that I wanted was $1,200.00 for 4 tubes!, LOL!, No, I did not get the tubes, but you get the point?