Interesting. I was actually going to go with something like this:
I've ordered the chips already, but not placed the other for the caps and all the rest yet.
I also tested a straight 9v battery across the pins and it worked too. It slammed the head all the way one way (and I would presume it would slam it the other way if I sent it -9v).
I've not used an H-bridge before.
What I want to do is get the voice coil to bounce around (hard), so it makes an audible clacking/clicking. Using the audio amp as a driver seemed to have the cool side effect of actually amplifying (acoustically) the squarewaves I was sending it, so you would hear the squarewaves as the head moved around on the platter, and if it was loud enough, that would move the head around enough to hit the end posts, which would then make an even louder click.
So would I hook the L293D up something like this?
http://luckylarry.co.uk/arduino-projects/control-a-dc-motor-with-arduino-and-l293d-chip/
Also it looks like the L293D has 4 outputs. Does that mean I can control 4 voicecoils with it?