Simplified 808 Snare
The real 808 snare has a more metallic bell sound. If you play with the tuning you can probably make it closer, but the real flaw is that you need a third envelope so the higher oscillator will have a faster decay.
The 808 snare is built out of 2 bridged-T oscillators and a white noise generator going through a high-pass filter. To get a really accurate 808 snare you would probably need either: A: 2 pingable self oscillating filters, and a high-pass filter modulated by an envelope, or B: 2 oscillators each modulated by independent envelopes, and a high-pass filter modulated by an envelope. So, Cascadia will probably never get exactly there, but it can get close.
The 808 snare has 3 controls: Level, Tone, and Snappy. The tone knob mixes the oscillators together. Adjust VCO-A sine amount in the mixer to change the tone. The snappy knob controls noise decay. Adjust envelope B fall to change the snappiness.
Page 14 of the 808’s service manual has a chart (shown above) that lists the pitches and decay times of all of its voices. According to this chart the snare has one oscillator running at 476 Hz (A#4 + 36 cents), and the second at 238 Hz (A#3 + 36 cents).