Hi Justin, I own both. I have the M2 on my laptop at home (BabyFace Pro on my tower) which I use with DT 990 Pro 80-Ohm cans, and I'm listening to After the Storm by Norman Brown as I write this. If I crank the M2 up to 10 I'll be doing ear damage. By the 1:30-2:00 position the volume is huge and punchy and I'm loving it. If my wife called out to me, no way would I hear her. The other night I plugged in my new 48-Ohm 770 Pro X's at the same volume without lowering it and my head almost imploded. The M2 has
plenty of juice for the DT series. If my 80-ohm open backs are this loud, your 770 closed back will probably be that much more.
So last year I bought a Volt 2 because of all you are reading... the charts and graphs showed it was somehow superior. Used it for a while, sounds great, and yeah, maybe I only need to go to 12:00 for the same volume, but I ended up putting the M2 back on my rig. Instead of selling it, the Volt 2 is now on my work PC tower with DT 990 Edition 32-ohm cans to listen to music there. Sounds great as expected, but the M2 is the winner in my book for a $200 interface for a few reasons:
- Sound quality is totally there
- Drivers work excellent on a 12th Gen 10-core/16-thread running Win 11 Pro and Cubase 13 Pro (and that's coming from a Babyface Pro owner)
- The Meters. Woof. 'Nuff said. Now that I have 'em, the two green/yellow/red blips on the Volt are a joke.
- LOOPBACK: easy-peazy on the M2, shows up as an input choice in Cubase. Volt 2 does NOT have it.
- The knobs: feel awesome on the M2 with a great grip surface. The Volt 2 has plastic smooth "yeah I guess they're OK" knobs.
- This may not matter to many but I like having separate 48V on each channel. M2 has it, Volt 2 has one button for both.
- The look of the M2 and the case with rounded corners just works. I've leaned my hand on those sharp Volt 2 corners by mistake, and believe me, they let you know they are there.
I've had the M2 for over a year and the Volt 2 for several months. My vote is M2 all the way. Ohhhh mannnn, those meters!!
So for the sake of testing, I just switched from the 80 ohm 990s to my 250 ohm DT 1990s which are my BabyFace pro cans, and I didn't need to push the M2 volume up due to the type of drivers in the 1990s. The charts are fine but really don't tell the whole story. Something else: These 1990s are quite amazing on the Babyface Pro, but I like the 80-ohm 990s on the M2 more... a bit better punch IMO (I also don't have the 8.5KHz 1990 spike corrected on the M2 right now). Point is, I don't believe you have to upgrade your 80 ohm 770s. Try the M2 first and just see how it goes, because to me, 80-250 ohm Beyerdynamic DTs are a totally sweet match for the M2. There is one member on here I talk with that got the M2 and 250 ohm 990 Pros and loves it, so I think matching your 770s to the M2 will not disappoint.