Pictured above is the preliminary assembly of the first two sections of a three section noise generator. The initial prototype is essentially a lifted collector white noise section cascading into a low pass section which in turn feeds a malformed state variable filter (not yet stuffed, obviously). I can't really call it that, because while it began life as a state variable it became mangled. I'm not going to elaborate further, because with the second generation prototype that section is facing a deep revision. The sonic goal of stage 3 is a pop-corn type crackle with adjustable intensity, please stand by.
Let's fast forward the initial build and actually listen to it:
Something of an acquired taste, perhaps. Seems also to have aggravated the youtube compression algorithms, I can provide a clean recording on request (but seriously, the second generation is shaping up to be improved, so why bother!)
Guts! Nothing much more to add here. I have slapped a primitive voltage regulation into it because I built it with a spot on 9 volts supplied by my bench supply, and every single wall wart I tried once built made it go haywire. Here's the believed to be accurate schematic of the initial prototype:
If you're a lunatic and want to build one yourself, I would advise contacting me instead of going off this schematic - unless you want to be saddled with all the issues that are under resolution with the current build. Amongst design flaws that are resolved at this point: the loading down of the low passed crumble output control when other stages are turned up got cleaned up with a common collector buffer.
Layout on the proto-board is also taking a more direct path.
With the exception of the initial noise source stages, I identified gain stages and buffers - then settled on a uniform configuration of values to simplify assembly. This created additional problems with the triac, but since the operating characteristics of each and every one seems different (I'm pulling from a really old bag, so it's anyone's guess if this is due to my circuit conditions or age/sloppy manufacturing tolerances) I needed to allow for calibration anyway. Now I can dial the triac up to the point where it's *not quite* stuttering and cutting out, which has improved the crumble of stage two substantially.
So there you have it, I may update on stage three once I get it sorted (lower right knob needs more travel/interaction), or we might take a look at something else. I'll try and touch base before another season goes by...