I have the Sennheiser HD600, Neumann NDH-30, Audeze LCD-X.
I use these with my SSL2 hp out, and with Qudelix 5K.
I spoke to someone about my impressions and his first question was: which dac/amp? and when I told, he just winked.
So my question is: is the difference this obvious with a more expensive dac/amp combo? Should I spend another 6-800 euro to get one? Do your headphones open up/perform that much better?
Get an RME ADI-2 and call it a day. The feature set it has will make it sound like whatever you want. The loudness feature is to die for. Everything is customizable. I freaking LOVE this thing. You have an IEM output in addition to the standard phones jack. If you have a PC with 2.1 it auto-switches PEQ and audio playback when you pop something in the headphone jack. Bass treble knobs to make quick adjustments. Worth every penny.
When people say things like “This dac/amp is warm” or “This dac/amp is analytical,” I cringe. With the RME you just dial it in to whatever you want.