After recent preamp tube change in my Bluesmaster...  I have found my preferred 12AX7's ...

Here's what I got going on:

Mullard ECC83 R.I. (in V1)

Tung-Sol 12AX7 (in V2)

Mullard ECC83 R.I. (in V3)

The Mullards have a really,really balanced tone but , they can be bright given certain applications.This is the first AX7 that I have turned the Pull-Bright Switch off (on the preamp vol). I am yet to find a tube  that is superior to the Tung-Sol 12AX7 that is under $20!

I believe I also have a Sovtek 5751 in my D-lator

Hope this helps some of you!

I've tried several EH tubes and never had any success with them. The lows were always boomy ( if thats even a term? )

 Yes it's New Sensors Reissue, @ almost $18 I think they're worth the dough ,fo sho

Regarding recommendation of tubes in preamp

V1+V2 = JJ 83s,
V3       = Sovtek LPS 83,

V5+V6= TAD 6L6 small bottle (RCA Blackplate copy) or SED Winged C

What is every1 been using in their D-lators? I was thinking I'd invest in a few NOS tube's to try out.

Interesting subject
I have no idea what's in mine. Maybe Erwin can shed some light.

 Two Rock has multiple proprietary circuit designs, that being said tube changing won't necessarily get you there.

  Most of their amps are based around the non-hrm vein although. The Classic Reveb has a buffered loop and that will change the sound also, not to mention the reverb circuit is crucial to the design platform also.

 And to note:

The 50w Classic Reverb is tube rectified;
 the 100w solidstate rectified.

 The Classic Reverb is also a Steel String singer influenced amp having tweaks from the John Mayer sig amp/ The Sterling Sig ( Exact SSS clone ) and the Custom Clean ( Two-Rocks take on the SSS/150w Dumble Land Special " The white glove SRV amp") ala "texas flood" in a can
 

 ....... I don't know, maybe I'm wrong.

 What are you using for speakers?