WAW, looks super nice.
What kind of batteries did you put in ?
Very nice boombox . Looks quite heavy (mine weighs 9kg and is therefore only semi “mobile”).
I like the fact that you did not go the bumpy road of trying to desolder the original encoders but just connected a second pair of encoders in parallel. I also thought about this but I was not sure whether they would interfere somehow. Nice to learn that they wouldn’t.