The SL9018 Headphone Amplifier USB DAC is a great product, well made, sounds fabulous. I tried it with the Sennheiser HD800 and the Audeze LCD-3 headphones. Sennheiser was amazing (holographic imaging), but too bright. The Audeze is smooth as silk. My source is a modified Wyred (new precision clock) Sonos with a LessLoss digital cable, and a NAS dive with high-rez FLAC rips.