I would avoid the 1980s Russian "Rocket"Voshkods 12ax7's. They are usually quite microphonic in my experience. I have some Philips Miniwatts which are identical to the Bugleboys and sound good. I also have experimented with rectifier tubes and found they play a role as well.
What are some favorite NOS 12AX7s for phono?
I recently bought a new phonostage here on Audiogon. I wanted something made right here in the States like my last tube preamp,so I pulled the trigger on one made by Jenison Audio;the Perpetuum model. I checked and he(seller: dividebytube) doesn't have one listed for sale right now, but I have been really happy with it. I have a VPI table w/ SME 309 arm, and right now I'm running a Dynavector 10X5 high opt. MC phono cart. I have tried Sovtek LPS 12AX7 tubes and liked the treble detail and "crisp and clean" sound they offer, but I am definitely looking for more of a 3-D sound. I am open to suggestions for NOS (or modern production) 12AX7 tubes that balance detail and warmth, sort of an "updated vintage" sound. I welcome any suggestions.