Introduction. The CP909 is Roland's TR-909 analog clap sound generator adapted for modular synthesizer use. The front panel contains all of the controls found on the original TR-909 drum machine, allowing you full control over the sound’s volume levels to mix with other drums, and accent levels. In addition to those original controls we have also added the unique TRASH knob, further enhancing this circuit. About the Making of the CP909.
Dynamics and Gain. Accent and Levels: Dynamic Accent and Level control of any drum sound in the mix is a big part of making a beat sound right. Dynamic Accent provides emphasis on a particular note through loudness. In analog circuits like the CP909, the accent pulse physically "hits" the internal envelope circuit harder and provides not only a louder sound but also slightly more attack (much like if you were to hit a real drum harder or softer with a drum stick.
TRASH Explained. The CP909 is based around a quasi-random logic-based noise generator and the TRASH knob controls the speed of this generator. When set at the max position (fully CW), pointing at the 909 dot, the generator is set at the original speed of the TR-909 and the typical clap sound can be heard. The TRASH knob gives you the option to lower this clock down, “trashing” the noise source which adds greatly to the spectrum of sounds that can be generated with this circuit.
