This mod is available for Afterbirth†, view it here:
http://steamcommunity.com/sharedfiles/filedetails/?id=893364253

Classic sounds and music for veteran TBOI players!
https://www.youtube.com/watch?v=aUPvtJyXPxc

All sounds and music tracks have their classic counterpart from the original Binding of Isaac.

It brings a very nostalgic experience for veteran fans!

If you own only Afterbirth, you can get this mod for it!
https://moddingofisaac.com/mod/3059/pure-classic-isaac-mod-afterbirth-ver

Cheers,
39Gamer39