I've been doing a lot of home recording lately, thanks to Fifty-Two Folk Songs. I'm using a Zoom H2 digital recorder and transferring tracks to Audacity for editing.

Lately I've been getting into multi-tracking, putting down instrumental accompaniments and layering vocal tracks (a couple of recent examples). I've very rapidly run into a problem with timing: my internal metronome is pretty good, but it's not accurate down to tenths of a second, particularly not between verses! I can get mismatched tracks lined up by wielding a virtual razor-blade in Audacity, but it's an awful lot of work; it would be a lot simpler just to keep in time by singing/playing along to what I've recorded already.

But how? The Zoom records onto an SD card (I'm using a 512 MB card at the moment, which is workable as I don't need to keep very much on the card at any one time). So I need a device that (a) takes an SD card and (b) has a headphone socket, and preferably (c) is cheap. I've got one such device already, but it's called a PC - which seems like overkill, as well as (more importantly) carrying the risk of unpredictable fan and disk noise. My phone is one of those primitive ones that let you make calls and send texts, and I haven't got an iPod (even if that would even work - iThings aren't renowned for their openness).

Any ideas?