The Back To The Future Delorean has its radio mounted on top of the TCD (Time Circuit Display). It was made by Coustic and is virtually impossible to find in the wild.
We did our best to bundle all usable occurances of the radio in the 3 movies here
For the A-car restauration (on display in the Petersen museum) the team used a Kraco KID 581 which is pretty similar but that has a a couple of differences (like the silver trim). You can compare both here