Should drive those without any issues, they're not that hard to drive. You want a little overhead in the power to enable you to play around with EQ as well, but I think you'll be fine with the adi-2 dac fs.

Atom II has a metal case :)

Yes, including in a very quiet listening room at my local dealer. I'm convinced any differences you heard are not from the hardware, but from your own expectations. Let's look at what a power cable does. Power is likely generated a great distance from your home, it then travels down uninsulated...

What utter nonsense. I'm an electrical engineer and there's no way a power cable could do any of that. I'm sure iFi will be happy to back up their claims with some sort of measurement? Those characteristics are really easy to measure.

I'm not having any of these problems. The ANC is not class leading, but works well enough for me. My main use is at my desk at work in an open office and while it's not a total blackout of background noise, with some quiet music on it's totally fine. The Momentum 3 Wireless was released 2...

Modern measuring devices are orders of magnitude better than the 'human hearing nerve'. Citation needed on where an unbalanced connection sounds different to balanced. There's no science based reason for this to be the case (except of course where chip amps can produce more power, and thus play...

Per manufacturer specs: DX300: G5: So if you're using a single ended cable @3.5mm then the G5 wins by some margin. Closer if you're using balanced on the DX300.

What is your gain set at?

Heaps of power for Sennheiser HD650

Does anyone know if the crystals are compatible with the galaxy buds 2 pro?

Check to make sure it's not set to only the balanced/single ended port (depending on which one you're using)

If it's pass through it should be totally fine. That's what the pass through function is for.

Define 'thicker notes' in some way that's not just audiophilese or the whole exercise is meaningless. Like checking which amp is more sour.

I've tried it with my Schiit Ragnarok 2 which can easily put out 20W+ into a 16 Ohm load - not that you would ever want it that loud! I'm sure it would bust the headphones before reaching anywhere near that.

That would absolutely be visible on a FR plot.