First use tonight at rehearsal with my rock band. This was a good test because I can use a wide range of tones with that band -- for some of the songs, overdrive, distortion, and even fuzz is appropriate.
I ran the VTRM straight into my power amp, which pushed a pair of Bergantino HS210 cabs (ported, with tweeters). I used my black Sadowsky P-bass... my favorite... strung with reasonably fresh LaBella Hard Rockin' Steels.
In short: I am really happy with this preamp! The Blend control is a powerful addition. It adds an extra dimension of tone compared to the VT Deluxe pedal.
In long, it's like the RBI on steroids. When the Character knob is fully counterclockwise you get that mid-scoopy thing going on, especially with Blend full up: think SVT Ultra-Lo. But as you rotate Character clockwise, you get more mids... and more distortion once you go past noon. I really like the RBI, but it only gave a relatively small slice of SVT. This preamp gives a much wider range of SVT mojo, and it definitely includes hot power tube mojo.
I A/B'd the VTRM with my Reiner (JGR) preamp. This is an apple versus an orange. The Reiner gives the pure tone of your bass, with four bands of EQ and nice overdrive that goes from clean to fuzz. The VTRM doesn't really do flat unless you keep Blend rolled way back. But I didn't get it for flat, I got it because I wanted SVT tones, and it does those extremely well... better than most all-tube preamps.
I kinda wish the VTRM had a vari-mid like the SVT: 200, 800, 3k (the VTRM mid is 1k). That said, it's fine as is... and easier to use. I was getting some tones that were really close to the 70's SVTs I owned back in the day. They seemed a little bright through my tweetered Berg HS210 cabs, but I was able to tame the highs with the passive tone control on my Sadowsky. I'm sure the VTRM will absolutely KILL through my Bergantino NV610... that's my "fridge killer" cab.
I'll probably wind up running the Reiner preamp into the rear input of the VTRM. I can then use the Reiner for clearer tones, the VTRM for wilder ones, and maybe volume boost. I also want to try the VTRM with RBI, and especially the RPM.
This Saturday's gig is with my "Motown band" where I'll be using my red P-bass strung with flats. More thoughts then, but I thought the pedal worked especially well with that bass, so the VTRM should too.