I've fancied playing around with a Pi for a while.
And I wanted a better DAC for playing mp3 files through the hifi.
And a better means of creating and playing playlists.
The Pi 4 looks like it should be a viable base, and with 2 USB3 ports on it, that's a lot of mp3 storage just plugged in. The extra board is essentially a DAC, but with some extra bits (incl a small screen) for touch control of whatever software I use for the playlists.
Might get some time to put it together and set it up tomorrow