I agree with Dr. E(MP)I agree with Edison, the sound of the EMP with top-flight, NOS EU tubes (mostly) and some select USA is wonderfullllll--esp. with Senn HD650/Cardas and good interconnects. The trick with interconnects are neutral and detailed. I am itching to try the silver cryo'd HP cable recently advertised on Agon.
When I have a bit more time, I'll rank the 'middle' tube and the 6DJ8 types. Suffice to say that for the 6DJ8, I agree precisely with Joe's Tube Lore. While he missed on some of the great 12AX7 and 12AU7 and only focused on the great 5751s--of which there are only 3-4 really, Joe is SPOT ON with his 6DJ8 assessments. I have just tried Siemens E88CC, and I am impressed. Better than Dutch---not sure, different. More air, more detail. Thin? Not sure. Amperex 7308 white shield USA '65 (matched NOS) are a little thin to my ear as well, but have not balanced/rolled with Mullards or CBS7728, for example, to flesh out the mids.
In deference to Edison, I need to try TFKs in outer position. The Early TFK ECC801S is spectacular, to my ear. I need more time to compare again to others. So far, the earliest 12AT7 types I have are Harleen '56, Hamburg '55 and some funky Mullard with super solid construction and funky D-getter that is part of a 'cage' over the top mica, and the tube is 3-mica. Early Tung-Sol (1953, Grey Plate) not bad for a USA tube.
EOS, the EMP with the right tubes beats a PPX3-6CG7 with the best 6CG7s--thoughs its a close call. The EMP is soooooooo musical, detailed, airy--and fairly transparent--but for musicality per se--defined by being able to listen for hours on end with admiration and no fatigue--it's hard to imagine better, though I hear the SP Supra just slays the EMP, and for the price, it should.
EMP is like my CJ-MV52--mybe not the MOST detailed (not always a good thing), maybe not the tightest bass (but very tuneful), maybe not neutral as a Switzerland, but so MUSICAL you melt into the sound and imagine the vocalist singing to you straight on and the band laid out in space backing him/her(it??). "It just sounds right", and what a stage! I feel the same way about the EMP.
While I really liked the ASL MG Head OTL III with the best of the best tubes, esp. for its price used, and my Sansui 1000A with the best of the best NOS, I knew I would sell both after 1 hr. with the EMP. I was lucky. Mine came with NOS Adzam E188CC and TFK ECC801S, and Siemens and old Tesla E88CC as backups. Good deal! Even the stock Ruby 12AT7 large chrome plate was not too bad, not bad at all in fact--but I need to go back and hear again, if I can find it.
PS. It was Edison's posts that got me into a frenzy buying rare 12AT7. Thanks, Edison, I think. I believe I have just about all of the great ones, +/- a year or so in vintage--except for the GEC2900--toooo expensive.