I bought used last month. This amp/dac combo sounds analog and smoothing. You could check review here: https://www.head-fi.org/showcase/audio-gd-r2r-11.22707/reviews Don't buy it if you care too much about measurement. I am selling for upgrading.

The condition is ok with two scratches on the top.

An important thing is that this is mk1 without new firmware. This means if you use usb connection, you will hear pop noise when you switch the application. However this is not a problem if you just play a long playlist.

One solution is to use a separate usb interface/ddc. If you don't have one, I could add a topping d10s with box for $50. Or you could get a usb blast for firmware upgrade.

Price:

$90 for audio-gd r2r 11 including g&s + shipping conus
$140 for audio-gd r2r 11 + topping d10s + some rca cable including g&s + shipping conus