Thanks project86 for this detailled review. Especially for explaining some of the technical background and comparing to some competitors.
From the specs it should be possible to drive a 880 600 Ohm, we´ll see.
I did not expect that you don´t hear large difference using the psu or not. If this thing can be used on the road too - even better.
What you think about changing the OPA2227? Could be worth the try or wasting time?
I stumbled upon a thread here quoting a japanese site:
That was of course for the AMP-HP.
So if anybody has some free time and bucks - that´s a list of options to try.
And I would not necessarily think that 50$ is an obstacle as some buy RCA-Cables about that budget - and I trust more in the ability of an OPAmp to change interesting things than of an cable.
The opamp in the AMP-HP is more directly responsible for powering the headphones. So it makes sense that swapping it would lead to audible changes. In the HUD-mx2, the OPA2227 is part of a differential amplifier circuit, which is used to improve common mode rejection among other things. It doesn't seem wise to swap that chip out since we don't know what parameters the circuit calls for. Frankly I'm surprised Audinst went with a socketed chip in that spot.
The OPA2134 on the line-out is another matter. Swapping that out could very well bring improvements, and it would be worth investigating.
Depends on the implementation of each. If we are talking about potential alone, I think properly done asynchronous USB clearly has the advantage. But there are so many variables that it can never be a blanket statement.
Anyone have any views on how the audinst hud-mx2 compares to the NFB 11.32 , or the schiit magni/modi combination?
In my area, the audinst hud-mx2 and the schiit magni/modi are both around USD250 whereas the NFB 11.32 is around USD337.
Likely setup would be laptop with hifiman he-500. (but do give views on how these dac/amps perform on paper)
[edit: would also be nice to hear what you guys think of the build quality (how sturdy/robust), and weight/portability]
seems the audinst hud-mx2 are pretty portable and of substantial build quality.
I can't speak to the comparisons, having no experience with the Audio GD or the Schiit. But I would think if transportabiliy was a concern, you would not be considering units like those which require AC power. In that case USB powered devices like Audinst or HRT would be the way to go.