I auditioned both of these preamps and went with the 6.5 MK II. There simply was not even close to a $5k difference in the sonics of the two. Maybe if you had some super revealing stuff downstream, you could talk yourself into the justification of the extra money. In my case, I used the savings to buy interconnects and source material. The 7.5 has a bit of additional slam, but it was subtle, at best in my experience. Re. using nos tubes, VTL ships the 6.5 with NOS GE tubes. I assume they do the same with the 7.5, at least in the audio chasis. I experimented with some NOS Mullard/Blackburn tubes which I found to be very sweet, but perhaps, a bit soft. I've now replaced the Mullards with some NOS GE Broadcast grade tubes that make the unit really sparkle!
