Hi Guys,
I own The T1 for about a month ago, and now that I have some time listening with it, I would like to update my impressions.
I Have a k271mkII and I got myself a hd650 for a nice price. I have the rocket logo 6n23p the 6922EH and I've found a used E188CC from RTC( suresnes factory ) early 70's.
First I must say the T1 drive the Hd650 very well, it is clear in the high, beautiful mids, bass is controlled ( depending on the tube ), with the fiio e11, my hd650 sounds very dark and somewhat dull, clearly underpowered. It still plays very loud, but it doesn't have the control of the T1.
For tubes now.
The 6n23p is very close/front sounding, it manages a good separation in instruments, but doesn't feel open, it's almost like the hd650 was a closed can. The mids are very good, a little grainy with good presence in the lower mids, male voices sounds very good !, treble are a bit too much some times with the akg. Very present and bodied bass, but muddy and not so controlled, sounds pleasing at first, but becomes unreadable with some fast metal for example.
I have to say, that i feel my tube is not a good one, because I have a lot of microphonics, if I tap gently with a pen on it while playing, i can hear a ringing, also when not playing i have crackling noise with volume to 11o clock for example. And i Can't put a +3db equ on any frequ without distortion...
The 6922EH is a more clean tube, still microphonic with resonance in the treble, but definetely more soundstage than 6n23p.
It lacks the body of the russian tube, bass is less present, but more controlled, mids are nice, but less than the russian, and the treble is too much with hd650 and overwhelming with akg. it sounds good with calm electro like the panta du prince ( thanks for that link
)and some atmospheric music.
The E188CC wow That's the real deal guys !
soundstag is amazing, it keeps the front presentation, and add width and depth to it, really cool, mids are wonderful, voices are so natural, no more harshness in the treble, very detailed and smooth presentation, bass is tight and goes deeper, but a bit less present, dynamics are better also, no more microphonics or noise thanks to it's mica springs, With both the senn and the akg, these are the winners to my ears, no doubt about it... with any kind of music
Remember it is subjective, and only my ears impressions
and from my experience, my E188CC is my best tube too. the more detailed , balanced , natural , tamed trebles , bodied and textured mids , clean and extended bass ... it's not impressible but it just seems this tube plays music the right way 
