Good question, I've often wondered this,
often wonder what djs (radio) and musicians etc listen to when they get home, I always imagined the late great John Peel had an ancient and very low tech hifi .....
I once saw ad in a hifi mag for EAR (yoshino) amps years ago that listed their famous customers and the only one I remember is Kate Bush......
Slightly off topic but I've know many a musician (non famous) that have been really into music both live and recorded but have invested very little in their hifi, the last one of these was a guy that loved music and his hifi but when I saw it and spotted he was using an acient PYE amp I asked if he had every considered ugrading as it might make his record collection sound a bit better , but he just looked at me like I was mad....... maybe he had a point !