I upgraded my Sennheiser 598's to Oppo PM-3's. I had been using both with my Schiit Modi 2 Uber, and found my PM-3's took the largest advantage there, as they are natively more accurate, faster, and full-bodied as a transducer. They were much more capable of transforming the more accurate signal into a huge improvement in SQ. I had begun to let my 598's to gather dust. Enter the Schiit Vali 2. It drives both of these easily driven cans with absolute authority, but we're not here to talk about something as simple as watts/ohms. I admit I drove my Oppo-PM-3's for weeks relishing every new detail. I enjoyed the new layers of detail and completeness of the sounds (We're talking 320 Kbps MP3's here). I will not deny that the sound I get out of my Oppo's has to be the best I've ever heard after getting my Vali 2, competing with my $3,000 5.1 theater (Comprised of Polk Audio and Yamaha amplification). I decided to brush off my 598's, and was VERY pleasantly surprised. The openness and detail in the highs remained, the acceptable soundstage was still present, but the Vali 2 introduced a fullness and detail of sound I had never heard out of them! If it were not for the slight graininess of the 598's upper register, they would compare with the significantly more expensive Oppos, as a direct result of the Schiit Vali 2. Point is, don't frown on a $169 amplifier just because it isn't a Ragnarok. If you own nothing better than a Fiio product, look nowhere else but Schiit for their Vali 2, and their likely as-impressive Magni 2 Uber. You'll be spending $169 plus shipping for something that takes $150 dollar cans to $400 can levels. $400 cans will sound better than anything under a grand. Don't hesitate, and buy some Schiit!