I wanted to be able to stream from my record player to ... well, to wherever, actually! Thanks to openwrt, ffmpeg and icecast, now I can.
I thought that I wouldn't have to worry about RIAA equalisation, because the sound card I have says it has a built in RIAA preamp (Behringer UFO202). Unfortunately, as it turns out, my one is broken - line in works, but phono doesn't. Fortunately, as it turns out, ffmpeg can take care of RIAA equalisation in software - problem solved!
Further details here: https://competitionlaw.gq/audio/streamingrecordplayer
The hardware choices were dictated by what I had around the house - but this, I reckon, has to be about the lowest spec hardware possible.
Suggestions for improvements welcome!