Yoo Yeh 250B
This is Yoo-Yoo (Yo-Yo) Yeh's 250B page
today Sasha let me borrow the small Radio Shack amplifier+speaker and i tried to get my roommates to listen to my heartbeat through a piezoelectric disk. not as good as a stethoscope.
on a side note, though, Radio Shack still sells those things, for about $15. i'm going to buy one of my own. very handy little thing, both amplifies, outputs, and has a headphone jack! powered off +9V external or battery.