Speaking from experience, the HD600 scales up really well. The better the amp and DAC, the better the sound. With my pair, I toggle between a Levinson integrated and a Sony headphone/DAC amp. With good lossless source material, yowsa! For the phones themselves, you can try different pads and/or upgrade the cables to balanced. I’m not an EQ guy, but I’ve never been disappointed with these great phones. I have others as well, but I always enjoy the HD600.