Posting this here since I gave this big ol response to mikoss and figure it was relevant:
Honesty I'm still teetering on the fence. On one hand, the T1 does sound, in total, better. Wider soundstage, just sounds cleaner, but still at the cost of some low end. The bass is still there, but it's not as strong, like someone set the bass down a little bit on an eq. On a whim, I did order a different tube since it was cheap, an Amperex ECC189. This tube, in comparison to the one it came with (6922EH Russian), was boomier and looser in the bass, but still weak on bass(just got done testing this one again and wouldn't say it's weak on bass anymore, but is more boomy). The rest was similar but but just a bit more muted. It didn't sound bad, just the stock one sounded slightly better. I wanted to try a different tube, just to hear something different to see how much a tube affects things.
For headphones, I have an ATH-M50 as my best, also tried with Portapros(bassy) and some IEM Sennheiser CX300s(even more bassy). I am now wondering how much different headphones would play into getting what I want sound-wise. If the M50s had the bass punch of either of the others, then I think I'd be good with this setup.
Here's the other hand. Just wondering if I'm steering myself in the wrong direction since the T1 seems to take out some bass. Then with, IMO bass light M50s, it gets even further on the cool side than I'd prefer. If I knew that I could get a certain tube that woud bring out good bass, then it would be easier. Coil mentioned a couple tubes that would probably be great, but they're either not available or are very pricey just to gamble on. If I knew that woud get me what I'm after, then it would be easier, but how much f the sound signature comes from the tubes vs the T1 itself?
I realize the issue with the M50s vs another set of cans is a seperate issue, it just kind of complicates the decision process. On some songs, the M50s with the T1 and stock tube sound great as is. Then I'll do the same setup but switch to the Portapros, and realize there's still some tight thumpage being missed. Now of course, the Portapros are lacking the mids and highs of the M50s. So the M50 can sound really good, but I just want that plus the bass side that I know I'm missing out on.
So, I'm guessing I may need to find some headphones that will fill that bass gap. Or, decide all the expense of the T1 itself plus tube hunting isn't worth it. Make any sense?
I do want to say thanks for all the info you guys have provided.