Time for new tubes.. which ones?

Parrot,
The original stock tubes are supposedly a Chinese Mullard double mylar knockoff T7.

Koestner,
Look up the thread in the Archives-"Tube Rolling for TAD-150". Lots of suggestions there. I just found it recently myself and am looking for suggestions also-mine was the last post. I have a pair of Sylvania 5751s on the way to try. I have a pair of x7 RCA black plates in mine now and they are an improvement over stock. I am also going to order a new pair of Groove tube 12AX7Ms to try.

Tube progression, so far....

Stock t7-flat sounding, rolled off top and bottom lack depth and width of soundstage
RCA x7a ribbed gray plate-better than stock
RT u7wa-ribbed gray plate-better than the RCAs but one was a bit noisy (couldn't stand it, wish I could have listened longer)
Brimar u7wa-gray ribbed long plate-better than any above-wider soundstage, increase in bass
Sylvania JHS 5751-wow, a direct hit, improvement across the board-Very nice soundstage width and depth, plenty of detail and prat! Gain match with volume control into my Mc DNA-125 is right on.
Mullard x7-short plates, halo getter-A MAJOR DISAPPOINTMENT-detailed but very flat-lost the soundstage completely (I hope everyone does not read this thread because these will be for sale soon!)
GT ax7m-playing now, just got them today-These are nice, very, very close to the 5751s mentioned above. They may lack some of the fine detail of the 5751s but not much. I can live with either.

I would like to try some nos 50s long plate Mullards or Telefunkens but I got to agree with Swampwalker, it seems a bit crazy to put $100 plus tubes in this pre (or does it?). For $50 a pair or so the 5751s or the GTs would seem hard to beat.

I have never fooled with cryoed tubes so I would be interested to get Stratosaur's impressions...

I have gone a bit tube crazier and have brought in several more to try
12ax7 RCA black long plates D getters-good air and soundstage in the can't go wrong with (CGRW) it category
5963 RCA long black plate D getters-also very nice, a little sweeter presentaion than above a tad less detailed
Amperex Bugle Boy 12at7 (made in France w/music clef on the side, big round getters-cream of the crop so far, for my preferences-very fine detail and air but tends towards brightness
Tele 12au7 ribbed plates-very well balanced sound does most things well, very livable
Amperex 12au7 med grey plates world logo-very interesting tube to audition finely detailed nice soundstage but may be brighter than some tastes allow.
I have some 5814 Sylvanias to get into the mix. I still would like to get a pair of tele12ax7 to try

Some of the CGRW others
Sylvania 12au7tw and 7twa
Sylvania 5751 grey plates-Tripple Mica
GT12ax7m gold series

Not making the cut
Mullard 12ax7 short plates
Mullard 12au7 short plates(better than the above Mullard)