Here’s a very good (possibly a classic now?) filter and VCA combo module from Manhattan Analog. The MA35 is based on the Korg MS-10 with absolute care taken to get the circuit as authentic as possible. Even the slight noise from the single chip VCA is authentic MS-10 noise! It has a two input mixer that you can overdrive and saturate your input signals with and switchable high pass and low pass. Lovely stuff! 🙂