Hi Ernie,
Back in 2010, after i bought the latest Franks with 100hrs new and before it was fully broken in, i started with tube rolling, it was my first tube amp (i was a SS person all these while). The stock EH300B was acceptable and reliable: it was good in the midrange but both ends were noticeably rolled off..then Sophia Electric Princess which after trying, i thought it to be lacking in bass but highs were very extended and airy, while midrange was a big improvement over EH300B.
I wrote to Israel if i should to try the Western Electric 300B which some says has the best midrange, OR the KR300B (there were others on the internet commented its poor reliability), his recommendation was simply "Shugang Black Treasure". Truly, it was the best among the few that i sampled. Black Treasure beats the Sophia Electric in everyway, especially the bass. If i remembered correctly, the background is even blacker.
However, this was my experience with Franks (i sold the black bottle 300B with the Franks) with 300B as output tubes. Frank (the amp) was honest enough that i could tell the difference between each brand of tube even before the amp was fully broken in. Well, my observation could be biased because the amps and tubes were all new but i could still tell their characteristics even when it was new. I think i had each tube running between 80-150hrs, switching back and forth. After the Franks was fully broken in, it was very open whereby both ends were more extended, soundstage is wider and deeper, and midrange is more transparent. Overall, a fully burn in Franks, would sound neutral, organic and 3D, and very much 'live'. Once i remembered that i was listening to a Jazz FM station through my Vintage Sansui Tuner, the music stopped and like there was air sucked out from the room. I dozed off at my couch and suddenly jumped out of it, thinking someone was at the door. I had goose bumps. LOL. My MK2 Dragons would sound very identical to the Franks though i never got the same goose bumps as i had with the passive preamp/Franks combo.
I am still using EH300B in my MK2 dragons. If i remember correctly, maybe i'm wrong, that Israel said the 300B driver tubes did not bring about a big change if i used the Black Treasure. This was in 2011. If you got a chance to try the Black Bottles in your dragons, please post your experience. Thanks
Jimmy
