Since I have a fairly long history with Pass gear and many brands of tube gear, I would like to offer my two cents. I also owned an X 350. Thsi was after owning a Sonic Fronties Power 2. I felt that I was missing a little with the SF am so I went to solid state. I felt that I was missing a little with the 350. So I upgraded to the 350.5 and wow! For the first time ever I felt that there wasnt a comprimise. The .5 gives the best of both words. It has thundering bass with sweet and delicate highs, and a midrange to die for. To me the .5 upgrade is a no brainer. Secondly, I mated it with an XO.2 preamp and the combination is a match made in heaven. The transparency, musciality and dynamics are jaw dropping. For the first time I have no desire to change my electronics. I am using this setup with 94db speakers, Tyler Acousitcs Woodmere. Source is a Levinson 31.5 and 30.6 combo. So what I am trying to get across is that the .5 upgrade with the X-1 preamp (because most say there isn't a significant sonic difference between the XO2 and the X-1)might just be your path to nirvana.
Enjoy your hunt
Enjoy your hunt