I put this info on the Mic lab forum, but though it would be helpful to put it here too. I have been working in my studio with the Valvet for several days and have been very impressed with it. I have a project studio which is a serious hobby for me. The best mic I have is a Blue Blueberry.
When I A/B the two mic's into a Langevin DVC, the best way I can compare it is by comparing converters. If you have a Motu converter, you may feel it has given you good results. It sounds better than the Behringer and Presonus converters you had heard in the past.
But when you then try a Apogee converter, you hear more detail, depth, and clarity. This amount of clarity is something that surprised me. It does not have the silky top end of a Blue Kiwi but with that mic being transformerless, it lacks the fullness of the Valvet. The U87ai has that classic low mid character which many including myself love. But the honkyness that many claim the U87ai has, the Valvet does not have. Instead you get a glorious full, clear, detailed sound that gently smooths the top end without adding a lot of color.
For adding more color to the mic, I ran it through my Voxbox. It does not add more character, but if more color is need, the Voxbox did it well. The people who record in my studio mostly do Gospel music or music where the vocals stand in front of the music. I think this mic would be a good fit.
Now this does not mean that all my other mics will collect dust. People like API pre's for rock n roll. It has a character that many like while it at the same time lacks the high end detail of a Neve 1073. I found in my short test so far that the Blueberry is more like the API. It lacks the high detail of the Valvet, but it also at the same time pushes the vocals through a mix very nicely and may be better on certain types of rock n roll type music.
After working with acoustic guitars, and more vocals, there is one word that really came to my mind with working with the Valvet.......refinement. In comparing it to some other mic's including another tube mic, the Valvet shown it's refinement that was very appealing. Again the refined sound may not be best for some rocker songs, but breath taking with other types of music. My other mic's seems a little corse compared to the Valvet. Depending on the type of song, that was either a good or bad thing. What the Valvet lacks is texture. It has a large clear,detailed, sound. I am not sure if I want a mic that lacks texture, then again if all my other mic's have it, this may be a great alternative. I found on acoustic guitars the full spectrum of the guitar was heard best with the Valvet. The Lundahl transformer adds some weight and fullness to the guitar. Unlike the U87ai I have tried on acoustic, there seems to be a more balanced character from the low's to high's. For rock music, I found my Neve Portico pre sounded best with it on vocals and acoustic guitar. On ballads, or Gospel depending on the vocalist, I preferred the Manley Voxbox or Langevin pre.
The first part of the chain is the microphone, and this is a great mic to start with. With it's full, detailed, and refined sound, you can experiment with different pre's, EQ's, and compressor to get different character, and sound. I read a review where they said the API did not match well with the Valvet. Most likely because the API top end is not as wide and extended so you don't hear some of the quality of the mic. All in all this is a very good mic very high end workmanship behind it. I found the high end easier on your ears compared to some decent Chinese tube mic's out there.