The 1973 Paperface VCF is a state variable 2-pole resonant filter that offers lowpass, bandpass and highpass outputs simultaneously.
1973 VCF Panel
The two CA3080's are not included in the BOM. This part can be purchased HERE
Input a sawtooth waveform into the audio input of the VCF with the cutoff frequency control fully counter clockwise. Patch a cable out of the lowpass filter and monitor the output level. Adjust the FREQ ADJ trim pot on the back of the module so that that the audio just starts to fade out and can't be heard.
J201 SMT Replacement (included in BOM)
The J201 JFET transistor in a TO-92-3 through-hole package is becoming harder to find. In this instance, it is possible to use the more common MMBFJ201 SMT SOT-23 package in place of the through-hole package. The photo below shows the proper way to install the SMT package in the through-hole footprint. Please check your manufacturers datasheet to provide the proper pinout for your specific part.