Also, it is common for people to come to this group asking for an X volt AC
adapter, when what they mean is an X VDC *AC adapter*, if you get what I
mean. It's a very common mistake so it's possible the OP meant an AC adapter
that puts out 3 VDC, but as he seems reluctant to take part in the thread he
started and give us some useful info on what he wants to achieve, we may
never know.

I'd put money on the OP needing a DC adapter, I can't see an MP3 player,
assuming it's portable, having rectifier/smoothing cap in it rather than in
the adapter, it'd be a pointless waste of space.



I don't think it's incorrect to call an adapter that puts out DC an "AC
adapter". It adapts the AC wall current to whatever the device requires.
It's a common term and one I've always used.