I got this dongle after reading this article and Jkim's to replace the famed Apple Dongle (US version) for less than $19, to pair with my Samson SR850 for PC listening.
Since I mess around with BRIRs and surround sound virtualization, which demands severe preamp cuts to prevent clipping (upwards of -10dB), I sorely need more output than the Apple Dongle can provide. Enter the JM20 Max. It is an excellent headphone DAC that's worth every penny. Furthermore, maybe my ears are fooling me but it also sounds a tad cleaner and "fuller" compared to the Apple Dongle, which I suspect comes from not pushing the DAC to its absolute limit (or better noise rejection?). With approx. -12db preamp, I usually set the Windows volume slider at 30-40% for long-term listening.
However, there's one thing new buyers must look out for. This thing gets HOT under use. The moment I plug it in it becomes warm to the touch. After 30-45 minutes of listening, it becomes surprisingly hot (I estimate around 40-45C), not something you'd expect from a tiny USB-C dongle. Such a high output, I believe, comes with higher power consumption and heat generation. Since I was kinda worried about the longevity of the dongle (and learning that someone's dongle suddenly died earlier in the thread), I put a small piece of computer thermal pad (like
these) on top of where the chips are.
So far I'm pleased with this purchase and might write an update once I've spent some more time with it.