Maybe I need to turn my audiophile card in, because I'm experiencing something ridiculously shameful
I finally upgraded my Arya to a Susvara because I've recently heard a Sus on an Oor, and thought it would be a good upgrade. It's a different sound (side-grade) to my Caldera, so I liked it.
After burn in, I customized the oratory1990 PEQ to my ears (-7dB preamp), then have been testing my new Sus on a Jotunheim 2 all day. Surprisingly, I felt that the Jot2 gets pretty close in quality to my memory of how the Oor sounded. I have tons of headroom on the Jot2 (6.0W@32Ω, ~60dB @9:30 on knob, high gain), so I figured I'd see how the Magni Piety (1.0W@32Ω) would do, fully expecting it to choke and die miserably - we all know how hard Fussy Sussy is to drive.
I had to put the Piety up to about @11 on high gain to get it to about the same volume. I didn't immediately notice a huge diff! Careful listening revealed a slightly collapsed sound stage. The Piety (on high gain) is extra bassy/warm amp, so I didn't feel like I lost any bass, but I felt like I could sense less dynamics – but not confidently enough to pass a blind test. Overall not as good, but it still sounded pretty good, I thought.
So what about going down to a weaker FiiO M11s (670mW@32Ω) DAP? I had to pump it to about 73% volume on high gain to reach the same volume. I finally noticed SLIGHTLY less bass, and maybe about the same of sound stage as the Piety. I think I might feel less dynamics, but not by a significant amount. I feel I could add a bit more bass in the EQ, walk around the house with Sussy, and not really notice a tangible difference to the Jot2 at all.
Ok, how about a Qudelix 5k (240mW@32Ω)? Sacrilige, I say. Well, it took ~90% to volume match. Umm... with A/B testing fatigue, I honestly can't tell between the FiiO and the Qudelix in USB DAC mode
To save time, I jumped to last place: Apple USB-C to 3.5mm adapter (13mW@32Ω). Volume matched at ~93%. To be scientific enough, I used a SPL meter + baffle to calibrate a 1kHz tone to the same 74.3dB on both the dongle and the Jot2. Subjectively... it was obvious dynamics suffered. The bass was flatter. Sound stage was much narrower. Imaging muddied. Compared to the Arya on Jot2, the Sus on the dongle is still a bit better on most metrics, but not by much.
However... Later, I was listening to music as I was researching the output power of other amps, and thought "man, this track sounds really good, just a bit loud"... when I realized my Jot2 volume knob wasn't reducing the volume: I was still plugged into the Apple USB-C dongle! The shame I felt – albeit my attention being elsewhere, this $8 dongle successfully tricked me into thinking I was using something literally 462x more powerful!
Now, I wouldn't claim the dongle sounds close to the Jot2. But the difference between a volume-matched dongle, Qudelix 5k, and Jot2 isn't as big as I had imagined it would be. I didn't get any noticeable distortion (I guess 50-60dB is "quiet"?), and anything > 100mW seems to have a "passable" enough experience. Of course, we don't pay $6k to just get a "passable" experience, so this is all moot point. Sorry for the long rant. I just found it funny that without critical listening, I couldn't even tell I was on a dongle! For shame...
I guess "Fussy Sussy wasn't really fussy, Was he?"
On a more serious note: Any opinions on Oor vs Bliss for Sus, for someone that EQ'd (at least on a Jot2) +7dB bass shelf, +2-4dB into mids, and -4dB the ~9.5kHz peak? This small experiment has seriously shaken my faith in whether I'd even be able to appreciate a difference on a Oor, Bliss, CFA3, etc. Are any of those a big noticeable upgrade vs a Jot2?