Rensek
Headphoneus Supremus
Many peoples hearing is altered due to damage from work or loud concerts--if you've attended one raucous concert, your hearing is permanently damaged. But the HD 6XX are a very popular headphone based on cost vs. return. I A/B'd them at Canjam on the same DAC AMP combo to be absolutely sure, and they are good sounding headphones, in fact they sound similar to my Sony's, but for my hearing my Sony's were better because I couldn't stand the bright sound of the HD 6XX's. It shouldn't be hard to believe that some people find certain combos unlistenable. Our hearing does vary THAT MUCH.
After looking at the DFR's specs, I would definitely, suggest getting a Magni 3 because it will serve as a great platform to try other headphones in the future. And will obviously, supply copious amounts of power compared to the DFR by itself, which is important with many headphones. AND it can be used as a pre-amp for amplifiers. Lots of bonuses involved.
It makes a great pre amp for powered monitors. I have a cheap set of Logitec 2.1 computer speakers. The magni and modi combo makes them sound much better then just running off the phone or PC like I did in years past.