I'm a big USB DAC/amp dongle fan, finding that for IEMs they often have the best SQ/dollar ratio compared to DAPs. They also have the portability advantage. I didn't see a thread on these, but mods please correct me if I'm wrong. In the past I've had the Geek Out USB DAC/amps, which were good except the infamous Sabre glare. Powerful and detailed. I recently tried the Lotoo Paw S1. It is sweet, smooth and detailed sounding but lacks power, resulting in limp bass and dynamics. Now I'm onto the Luxury and Precision W2, and it's the best I've heard so far. It's got a neutral to slightly warm signature, with plenty of detail but little digital nastiness. It's got plenty of umph, with deep full lows, but also plenty extended highs. All in all it sounds pretty tonally balanced to me. It's got a remarkably black background: Orchestral pieces that start quiet and swell gradually can be heard from the very starting moments. The stage is relatively wide and precise. It's not as powerful as some of the GOs, so I wouldn't bother trying to use it with full sized HPs, except maybe balanced with easy to drive HPs like the Verum 1s. All in all it has better sound than my Cayin N3Pro, excepting the tube magic idiosyncrasies. The size is tiny with the length just slightly longer than the width of a credit card. The firmware works mostly fine from all my sources including my phone, with a few glitches here and there. For example, occasionally on foobar I have to restart a track to hear it and with my Shanling Q1, it cuts off the first half second of new songs when switching. It works perfectly with my Pixel 3a.