This quote from Enjoy the Music review of the Mercury 2 is spot on.
You should know that my favorite preamp tube has been the 6SN7, and specifically, its military specification RCA VT-231 due its big tone sound. Since deHavilland was and still is a supporter of the 6SN7, you might get the impression that the 85's sonics are pretty much cast of the same mold. That is definitely not the case. The 85 insists on greater tonal neutrality, lacking the 6SN7's robust upper bass and lower midrange. To my ears the VT-231 generates a vintage romantic balance that complements the power range of an orchestra and does wonders for the foundation of a jazz combo. The 85, on the other hand, excels in the areas of harmonic textural delicacy and clarity. As a result, the Mercury offers an exceptionally clean window on the soundstage. It gives the soundstage the "Windex" treatment. The chronic veiling that afflicts lesser line stages vanishes like smoke with the Mercury in the chain. There's a purity of expression that makes it possible to resolve low-level detail even at low-volume levels.
I initially was disappointed wondering where the punch was in some familiar recording but the more I listened, the more I came to appreciated the more neutral presentation of the Type 85 over 6SN7 tube
A very happy camper with my Merc 3
