Tiptop Audio BD909 (used)
Bassdrum synth
Just like the TR-909 this bassdrum module has controls for tune, level, attack and decay but with an extendede decay range.
In addition there´s an adjustable accent with accent socket (prepatched to the gate input), attack and decay parameters for the tuning, voltgae control of the tuning and a voltage controlled overlaoad for distorted sounds.