I've been able to download mp3's just fine from my Samsung Tab 2 with JB 4.2.2.
However, I can't download mp3's on my Nook HD+ running KK 4.4.2.
It seems as thought KitKat is intercepting mp3 calls. It always launches a player in FireFox or Boat when I click on a link ending in .mp3, even tho I have disabled plug-ins in those browsers. It will not let me "save a link" to an mp3.
I'm guessing this is a default behavior somewhere. But even though I've frozen Apollo, the mp3 player in KK, I still get this behavior.