For volume matching, I use two apps: Sound Meter, and Noise Meter on the Play Store. I place my phone between the drivers, and play pink noise. Was able to get basically the same decibel level on both programs, and both the Magni and SA-31. Not exactly the best tool, but I did this AFTER doing it by ear, and I was basically spot on with the app.
Listening to the differences on the Magni. The Modi is a little brighter than the ODAC. It's stupid to even put a number on it. The ODAC is just a teeny smidge more fleshed out, while the Modi is just a little sharper. You can tell in the bass as well. The HE-400 hits just a liiiiiiittle harder on the ODAC.
Is it enough to choose the ODAC over the Modi? Hmm... that's a tough call. Definitely not price-wise. I'd say the Modi is 99% the ODAC.
Believe it or not, I desperately want the Modi to be better than the ODAC, so I can put the ODAC for sale, but I can't lie. The ODAC is a very tiny footstep ahead.
If you're gonna get the Magni, just get the Modi. No reason to mismatch unless that price premium for that small micro percentage increase in body is worth it to you. The Schiit stack is definitely a fantastic combo for $200. If you're gonna nitpick over the details that the ODAC is worth it to you, then you should be looking at another amp anyways.
The difference really isn't enough to get a headache over. I'm sure the vast majority wouldn't even notice. Perhaps with the right headphone and super analytical listening, but who's gonna do that?
I enjoy the HE-400 off both the ODAC and Modi and both my amps.
In fact, I'll consider the SA-31+ODAC my warm setup, and my Magni+Modi my neutral one.
with flash, because I have horrible lighting in the room...
Don't let the image fool you. The SA-31 is 1.5x the width, and about 3x as deep as the Schiit stack. ODAC wedged in between them. Edited by Mad Lust Envy - 12/23/12 at 6:50am