"This is quite a unique VCF module, and my Music Lab contains three of them. The filter cutoff frequency can be adjusted with ultra-precision using a 10 turn lockable potentiometer, usually only found on VCO's. The filter Q (resonance) is also switchable between normal (fully resonating) and limited. The outputs are low pass, high pass and band pass with both level and +/- phase adjustable. The inputs are duplicated to nuclear physics spec Lemo connectors which connect to the virtual earth inputs on the module, allowing input signals to be summed directly on the Pin Matrix module. Also note that two of these modules are designated ML1501, although they are actually ML1502's underneath. The ML1501 panels have a slightly different layout which includes a voltage controlled Q input, although this is not connected internally and the PCB's are all designated as ML1502."
