[Kiwiburger]

Sounds like a very fast tremelo effect (amplitude modulation). It's a bit too square-wavey and clicky sounding for my taste. I wouldn't be surprised if it's a virtual synth, and I didn't hear any rotory speaker or emulator.

I have plugins like Combosistor that could pull off that sound. Or a tremelo plugin could add that effect to a synth or organ. Square wave tremelo can work well sometimes - but some plugins are too perfectly square (sharp on/off) and clicky. The good ones round off the corners of the square wave - and analog circuits naturally are less sharp.