Caustic Song file (optional):
This is, very much, related to, and inspired by Nitro 27's KS resonators thing. Something in the OP, there. You don't need a noise generator. The Decay envelope would do it.
This K-35 filter. It's based on a, classic, simple, analog design, but it is digital. But it's doing all sorts of things that are, usually, the reserve of analog filters. Slew, LFO, Track and Hold. And also, it would seem, self oscillation ( with a little bit of a kick start). And you can use it to play tunes.
Don't let anything, like this, anywhere near an audio output, until the oscilloscope says 'Yes'.
And keep the master output gain low. Any change of parameters can take a while to stabilise, and could, possibly, scramble.
You have been warned.
And this is new territory for me, so a lot of this is observation and speculation. OK?
So, let's get a sine wave out of it. No feedback loop for this. Front panel Cutoff down, Resonance up. The shortest Decay envelope. And a bump of DC into the Resonance 'mod' input. This is the 'critical' bit. Too much will scramble. If that happens, front panel Resonance down and up will reset. The Resonance bump, kind of, behaves like the Decay control. That's why 'short envelope Decay'.
It would seem that some kind of signal needs to go into the Cutoff 'mod' input. I'm using note CV in most of this file. Don't waste any time trying to scale it. That won't happen. You can use the front panel Cutoff control to tune these things, but, I wouldn't bother. And too much of that can scramble. Don't spread notes from the sequencer across too much of a range. I suggest you write them first and go with whatever happens.
Feedback. This one doesn't need the Resonance bump. It's stabler without it. It does, however, need that front panel Resonance control turned up. I left it down so you can see what happens. Turn it up and press play. This one needs a lot of attenuation.
Activate. As it's name implies, that's what you have to do. I haven't found any automatic way to do it. This one's pretty wierd. It's the same setup as 'feedback', but the result is very different. Press play, and turn Resonance up. It will scramble. Turn Cutoff down. There's a lot of 'derailing' going on here, but you can get rid of most of that. By turning the feedback mixer output right down (?). There's a blank mixer by the scope. You could run that output into the filter, and it wouldn't stop oscillating.
But, I suggest that you turn 'input 1' from the Decay envelope, down and leave a bit of feedback in there. It sounds nice. LFOs are running this one. Play around with them.
And once the machines with feedback are up and running, they won't stop unless you reset them.
A few other K-35 things.
LFO output Depth is a bit unstable. On the other hand, 3 units of rack space for an LFO with random Depth is, pretty good, value.
The lag processor will outlag the lag processor.
For control signals, the Track and Hold system is as good as any. The Decay envelope sets track time. Or, use the DC Square output of an LFO.
Mixer 2 seems, pretty stable. I think :)