This Module is discontinued.
Tuned twin-T percussion module
THIS MODULE HAS BEEN RETIRED - once these are gone, they're gone for good. It will be replaced by a 2HP module with the same functionality.
Once upon a time, I had a twin-T bass-drum module based around the CD4069 hex inverter - it was OK in that it did the job but tended to be a bit touchy with regard to tuning.
Fast forward a bit and there's a new version based around an op-amp instead - the tuning circuitry has been simplified (big time) and the whole assemblage is somewhat better behaved than its predecessor.
There are three controls on the front panel - two of which control the tuning and (to a lesser extent) the damping response of the twin-T filter and the other to control the level of the incoming trigger signal. In common with most twin-T circuits, it will trigger on both the rising and falling edges of a gate signal - depending on your use-case this may or may not be what you want.
For best results use an envelope generator (such as the DV3) to generate a decaying pulse - anything with a peak above 0.7V will do the job, otherwise the transistor on the input won't fire. The filter tuning has a fairly wide range, so you can generate anything from 808-style kicks all the way up to clicky woodblock effects; get two or three and you've got the beginnings of a modular drum synth.
NOTE: These units are fitted with Alpha pots, so they're a bit more expensive ...
Mounting screws (M3x10 machine screws) are also supplied, as is a suitable power cable.
