What can I say. The HD800 being 300ohm have a pleasing response with otl tube amps. After being in the hobby for over 10 years and this being my first audiophile headphone I ever bought, the combo of a (modded) HD800 and an otl tube amp is just something amazing. Hd650 with tubes are also a great combo (well it's a meme at this point for a reason)