What Effect is Frank Zappa Using Here???

So I've been collecting Effect pedals for about 6-7 years, and I've personally collected about 50 pedals or so.

That being said, I'm absolutly baffled as to what effect Frank Zappa is using in this track:

https://www.youtube.com/watch?v=zg19hjBuGq8

^Finally found this tune after hearing it about a year and a half ago, and not knowing the title of it...

I've heard a friend say that he's just "Plugging his guitar straight into the console..." whatever that implies. It sounds to me like some sort of envelope-filtery... thing, but much more 'harmonic' for lack of any better discription.

So... "What is it Batman?"

Okay, without listening let me point out that Frank's console was a custom job made by Paul Buff of Alison Research, later Valley People/International. It wss loaded with Gain Brain and Kepex dynamics modules which can do some wild things. So direct input to his desk has a lot of colorful processing available.

Okay, without listening let me point out that Frank's console was a custom job...

Not to be a pain in the neck, but the effect is right there from the first few seconds, so no skipping needed.

FWIW: the internet says Oberheim VCF-200, which has a sample and hold function, as heard here and here. Whether or not he had that circuit built into his console, and whether or not you believe these hearsay sources on the internet, a filter being modulated by a sample and hold circuit is a highly plausible explanation for the filtery-bit of what you're hearing.

Oh yeah, the lesser known brother of the oberheim phaser pedal. 2 pole filter with sample a nd hold modulation, you could probably do something similar with any mono synth with an external input and the ability to open the vca up to bypass the envelope gen... or eurorack.