this amazing filter originally comes without CV control…but that’s what I didn’t like, so I grabbed a few vac paks (synthrotek) to create variable resistance via CV…I added 2 controls over different areas of the frequency of the first filter stage, which I can also put in series via a switch…then I added 1 CV control to the 2nd stage (frequency again)…works and sounds really good…especially well suited for weird percussive sounds and rhythms…