Can't believe it took me so long and that I haven't seen mention of this, but tried to run CV into the Xerograph Dlx today... WOW. The 5v CV out from my Rucci 8-bit box totally works, in a limited but very cool way.
If you're unfamiliar with this 8-bit synth thing, it basically has a number of preset sequences that you can adjust the speed and pitch/range of. The speed knob works also as a depth control with the Xero. In different modes I got slow to mid-tempo tremolo throb effects with the signal cutting out between the pulses, or resonance popping in if I set that high. Other modes or tempos gave a shallower fluttering in the higher frequencies. Most settings were very pronounced with the sensitivity off, some also yielded interesting effects with it turned up more, which usually made the fluttering go away as I was playing and come back as the sound decayed.
I'm sorry I can't make a demo of it right now or explain it better, but try it if you have a suitable CV able thingy, really expands on the possibilities! Filter trem!