My Boss DR-110, a probe, and oscilloscope software - Visual Analyser 2011. You can short the different individual oscillators to ground, and they'll come out the audio & headphone jack.
There's a great breakdown of how the circuitry works at http://www.sdiy.org/richardc64/new_drums/dr110/dr110a1.html - but some of the frequency values there (related to the cymbals) didn't sound right to me - though it's possible I misinterpreted what's going on at that page.
I started out with a sample-based version in 2011 or so, but the link I posted uses synthesized sounds, in updates I made last year. Have a closer look at the javascript as referenced in index.html and take a look at dr110_synth.js
This is probably most evident if you play a roll on the snare or the handclap. A free-running LFO on the noise sources for these instruments prevents "machine-gunning" like you get when you roll a sample.
https://github.com/leviathant/BossDR110/blob/feature/synthes...
To the parent, what did you use as the reference for the synthesis patches and parameters? I wouldn't mind trying something similar in ChucK.