Best answer by Ken_Griffiths
Ah right, you can perhaps also try the below, to see if it works for you. That’s if you prefer to not compress the line-in audio. It may work in some instances:
In the Sonos Controller mobile app, switch back to 'Uncompressed', and in the 'Line-In Source Name' for your turntable's Line-In, choose 'Airplay Device'. This changes the buffer depth to ~500ms, which may be enough to deal with temporary interruptions you were seeing with your turntable.