@Yoram Diamand The Mjolnir for sure, but SQ wise they are both very good. You won't miss anything with your T1 as far as detail goes. The T1 is a smoother sound while the Octave is more dynamic sounding. Faster, crisper, more lively, gets quite a bit louder. The T1 has a smoother sound signature and doesn't match the gain or dynamics of the Octave but all in all the T1 is surprisingly good and provides all the detail one would expect from a Stax amp.
I use a preamp to control the volume on the T1 and of course, the Octave as well since it requires a preamp or amp with gain control. If I'm listening to the Octave with the gain set to let's say, 30 on the preamp, I'd have to crank the preamp up to 45 when using the T1 to get the same sound level (estimated due to doing this with my ears) and the octave has a lot more headroom. The T1 starts to break down at higher volume while the Octave keeps pushing out clean music. The Octave can go as loud as I want...until it hurts and still is clean sounding while the T1 starts to fall apart before reaching any blistering levels.
At lower volumes, though the T1 is great and I love it. So is the Octave though and it sounds livelier. More energetic.
If I only listened to my music at lower levels then I'd be hard-pressed to pick one over the other. They both sound great. I suppose it would depend on if you prefer a smoother tube sound or a solid-state sound. I'm a big tube guy so I dig the T1 but I admit the Octave is the better amp.
Hope this helps! If you have any more specific questions let me know.
/edit just tested them together and the T1 needs to be at 43 on the volume of the preamp to match the Octave at 30 on the preamp.