Hi I've only had this new DAC/Amp for a day, but I felt compelled to write an initial review of it as I'm astounded by the sound coming out of this tiny thing! I currently have it connected to my iPhone 6+ using the Apple Lightning to USB camera connection kit and the supplied short USB to Mini-USB cable, but have also tried it with my Lenovo Yoga 2 8" Android (KitKat) tablet using an OTG adapter. Both work perfectly and sound fantastic! I have my Ultimate Ears Triple.Fi 10 (with ACS custom silicone moulds) connected to the NX2 and position 4 on the volume dial is comfortably loud enough for me. Without any music playing, the amp is virtually silent; only a slight (and very quiet) click is heard through the headphone when toggling the power switch, but otherwise there's no real white noise to speak of. Music played through this unit sounds very detailed but not over analytical, instrument separation is great, there is no sibilance at all and it appears to have plenty of power on tap (at least for these IEMs). I'll try with a selection of other headphones later, but for now I'm really happy listening to albums using this combo. Build quality looks and feels good for this price point. Since upgrading from my iPhone4 years ago and losing the 30pin dock which allowed me to use my Qables LOD cable, I've not been happy using an amplifier with my phone as I don't like the thought of amplifying an already amplified source rather than as line-level signal, so the NX2 with its built-in USB DAC at a fantastic price is just what I've been looking for! Great work Topping!