Original songs only?

[Ricklh]

Just a basic question: is it standard practice to only post MP3's of original material? In other words, if I did a cover of an old instrumental or something along those lines and posted to a site, is this a violation of copyright laws? Just curious, so I'll know what I can post and what I can't.

 

[Nate74]

I posted an old Johnny Cash song that my band covers and no one jumped down my throat about it...