The CP909 by TipTop audio is a clone of the hand clap sound from Roland´s TR-909. Sound-wise it´s like the original but there´s an additional Trash parameter for creating a rougher sound.
The CP909 clap effect is made by a special triple-saw envelope generator that controls the gain of a VCA. The sound source feeding into the VCA is made by a quasi-random logic based noise generator; some might call it "digital noise" though this term might be misleading in today's world of microcontrollers and sound samples. What really makes the noise generator is a ring of logic gates, so primative, so 80's, and that's the sound of the 909 Clap!
A trimming potentiometer on the PCB allow you for setting the balance between clap and clap reverb. the default setting is exactly the same as on an original 909.