There's not a lot of information about this unit outside of the few reviews on Amazon. So I actually bought the thing, and I'm glad I did. I've been playing with it for a bit now. Here's how I tested it so far. Three sets of headphones from Three different sources:
Headphones
- Audio Technica ATH-M50x
- Audio Technica ATH-SR50BT
- Rockville Pro M50
Devices
- Alienware laptop
- Lenovo ThinkPad
- Samsung Galaxy S22
I've compared various tracks streamed from Amazon Music (Ultra HD only.) Whenever possible, I'd plug in the headphones directly to the device, and with the Fosi Audio DS1. I also compared with the Blue Tooth with my SR50's from my phone, and from my Alienware. In addition, I used my SR50's in Blue Tooth, plugged in, and plugged into the DS1 while playing games.
The DS1 definitely improved the sound over plugging in directly. Mostly in the high end (symbols, high hats, strings, etc.) I did notice more dynamics and liveliness in other frequencies. (Drum hits sounded richer, the attack of the bass in some Tool and Moonspell songs, etc. )
When it comes to build quality, I'd say this is fairly solid. It's got a metal housing. The USB-C cable snuggly fits in ports, and it even has a USB-A adaptor. It gets a little warm when listening, but not too much (body temp'ish.) It supports the two standard headphone jacks, and has a volume control.
At some point, I'd like to get myself some headphones that have a higher impedance (been looking at the Bayerdynamic DT770's at 80
Ω or 250
Ω .) That's not happening anytime soon... but when it does, I'll update.