sound interface

[z812]

do you need a sound interface to have an aftermarket stereo in a '86 nissan 300zx GLL Model? Stereo works, but there is no sound. this car has a factory amp with cables coming from it to the stereo instead of speaker wires.

[GlassWolf]

if you want to use the factory amp and speakers you'll need an adapter yes.
otherwise just bypass the amp and replace the speakers with new ones.. the factory ones are paper with foam surrounds anyway.. probably dry-rotted to dust by now.. they weren't meant to last 20 years when they were made :)