HATS909 is an open / closed hi-hat generator using a clone of the Roland TR-909 circuit. The lo-fi 6-bit samples are passed through various analog circuits such as filters and envelopes to create the sound.
OH and CH decay control, tune, level, and accent can be controlled. If both OH and CH gate signals are input, OH is output.
As an additional function, tuning (FM) or volume (AM) voltage control is possible, and it is switched by the switch on the center right. The switch on the center left is normally used for "909", but if you switch to "RAW", you can output a sound that skips all circuits except the sound source part.
The point is that the volume is designed to be very loud so that it can easily respond to various distortions. Fine adjustment of the volume is possible with the accent knob. Simple, but recommended as a modular, high quality drum sound source.