The T1 is a different beast altogether. The impedance hump actually reaches a massive 1400 ohms - so if you don't have enough voltage on tap, the first thing you are going to notice is no real body to the bass. And this gels exactly with what you've described so far - about the T1 being too bright, and not as big a difference with your other cans. IMO the T1 shines with amps able to output higher voltages, and OTL tube amps particularly.
You don't have to spend megabucks for the T1 to shine. I think I already mentioned the Audio-gd NFB-15, or for tubes, something like a LD MKIV does very nicely. But if they are underpowered, you won't know what they are really capable of. You'll get the volume - but not the whole (correct) balance of frequency spectrum.