In this video I review the Fosi Audio ZH3, which is Fosi’s new DAC + headphone amp, and I’ve been using it both as a DAC in my stereo system and as a headphone amp for a couple of weeks. I also compare it directly to the ZD3, since that’s what I was using before. I go through the specs and I/O (AKM4493SEQ inside, 1/4" and 4.4mm balanced headphone outs, XLR/RCA outs, plus RCA analog in), and then I spend a lot of time on the user interface—because that’s honestly the biggest surprise here. Fosi engineers clearly listened to feedback. The ZH3 menu system is more mature than the ZD3, with useful quality-of-life features like screen brightness/timeout and auto power-off, plus filters and tone controls (in headphone amp mode). Sound-wise, the differences versus the ZD3 aren’t huge, but I did hear the ZD3 as wider in soundstage, while the ZH3 had better center focus and a bit more body and mid-bass impact. The ZH3 is almost perfect, but there is one real problem: with sensitive IEMs, I can hear background hiss when tone controls are enabled (bypass off). Flip bypass on and the hiss goes away immediately, so my recommendation is simple—don’t use tone controls with IEMs. If you need a headphone amp, the ZH3 is the pick; if you need HDMI ARC or Bluetooth, that’s where the ZD3 makes more sense.