9/2/2013: RoHS has changed a lot of the parts. I found a good-enough FET for the time being, PF5102.
1/2/2012: Updated list quite a bit. Resistor part numbers might be a bit stale; just use a nice 2% tolerance metal film.
Transsound capsules can be purchased from JLI Electronics: here.
Also, the 1Gohm resistor (yes, that's 1000 Meg) can be hard to find, and is usually expensive (more than $3 each). If you're looking at a different supplier, check for the 1Gohm resistor first. Mouser does carry them, and Digi-Key sometimes has them as MOX200J-1000ME-ND. I'd recommend the MOX200J if you can get it, since it is the size of a regular 1/4watt resistor.
|1||78-1N5242B||12V Zener Diode||512-1N5242B|
|2||0.47uf||50V Polyester Capacitor||140-PEI2A474J-RC|