1. GE 5751 black plates & triple micas. These babies did it all. Great extension both ways,great soundstage with lots of air. It just sounds right.
2. RCA 12ax7 grey plates. Very close to the GE 5751. Not quite as much "air'.
3. Sovtek 12ax7LPS. Nice tube. Not on the level of the RCA or the GE in my opinion anyway. I felt it was very listenable though.
I also tried out a set of Amperex Bugle Boy 12ax7's but I didn't like them. They had great highs and low end but everything else just wasn't right for me. I also have a set of Amperex 12ax7's with the orange world globe on them but I fell in love with the GE's and never bothered to try them out. When I do try the last Amperex tubes I'll post what I think.