[Re-posted from the Formula S thread)
I finally had the chance to do a volume-matched comparison between the FS/P (TT2/M-scaler on DAC duty via superconductor V RCA) and the TT2 dual XLR3 output (with Moon Audio female-to-female XLR3 adapters). The headphone is the 1266 TC + Superconductor HP cable. I struggled with whether I should sell my FS/P stack to free up some funds and try something new (maybe the CRBN?) but I don't think I will be doing that anytime soon.
I used a sound level meter and several test tones (40hz, 250 hz, 1 khz, 2.5 khz ) to make sure the TT2 and FS were matched.
Bass. The FS just gives more present and impactful bass than the TT2. You can feel the oscillations of bass tones and even more sub-bass rumble. It just seems the FS is more interested in delivering the sensation and tactile experience of bass than it is in the tonal accuracy of bass. It's on full display here and bordering on supernatural. Some people talk about bass "grip" and I've always wondered what that referred to. I think I'm starting to understand now, maybe. This doesn't appear to be related to pure power, as TT2 outputs many more watts from its dual XLR compared to the FS. The FS just does a better job squeezing out that last drop in TC's bass technicalities and prowess, and it does so effortlessly.
Mids: Vocals feel slightly warmer, and slightly more forward. Tonally, I'm hearing more body overall. The TT2 conversely does mids with a tiny bit more brightness (and probably correctness) and seems to have an edge in microdetail. The TT2 has a better ability to render actual vocalizations (word-forming, spit bubbles popping, etc). I suppose the slight loss of transparency is the price you pay.
Treble: I'd give this to the TT2, which treats treble a little more delicately. Let's take the hi-hat for example. On some tracks, the TT2 really nails the metallic vibration and coarseness of a drumstick against the hi-hat. The FS seems to focus more on the impact itself with less of the sizzle (more attack, less decay if you will). It might as well be a wooden spoon against that hi-hat. Again, not as delicate as the TT2's handling, and not as realistic. Keep in mind this is with the superconductor HP cable, which to my ears, already imparts a smoother and more subdued treble experience compared to the stock cable, which allowed a little too much energy in that region for my tastes. Who knows, maybe the Formula S actually tones down the stock cable treble juuuuust the right amount and inches it closer to the TT2's handling.
The Formula S / Powerman combo really makes a lot of sense in the context of the TC. I can see why it's been said that this amp tuned for this specific headphone, since it augments its best feature (the bass), while improving on its main two sonic flaws: the distant and slightly cold mids; and the (occasionally) excessive treble energy.
As for other factors like soundstage dimensions, I honestly can't tell the difference -- it's like comparing humongous vs enormous. Let's say it's a tie.
[edit: I went back and assessed the spatial qualities of the FS. I honestly prefer the TT2's overall abilities here. I agree that the TC does have more instrument separation and a wider stage. Also the image seems taller, as well. But the stage on the FS is sadly flatter in the anterior-posterior direction. I can offer a potential explanation for this loss of depth: maybe it's a combination of the mids being brought more forward, along with the stereo separation between instruments/sounds increasing mostly laterally on top of an already wide stage. On the song Lake Street Dive - Use Me Up and Postmodern Juke Box - Hey Ya!, the effect is that the back-up singers sound like they're at your 9- and 3 o'clock, instead of in front of you at your 10 and 2 (on the TT2). I hope that makes some sense. Overall the TT2's spatial handling seems to preserve more realism, which I do value over the stage being wider.
What all this means to me is that as long as I own a 1266 TC, the Formula S / Powerman will stay with it. The TT2 is still impressive and very capable of driving the 1266 (not to mention, being better at showcasing the TC's detail and imaging prowess) but we're talking about obtaining that last 3.298% of peak performance, and I'm fairly confident the Formula S unlocks that (without my having to pay an absurd amount for a WA33). YMMV of course
