video comparator circuits

heres some schematics for the comparators. type 1 is used for sync processing. feed any h or v sync signal in, patch the outputs to the sync input jacks on some vcos, and twiddle the knobs and flick the switch till you get sync lock. easy. no pcb layout for these as i built them on stripboard.

type 2 grounds the negative side of the threshold pot, and takes the +V side through a switching jack, so you can insert an external signal to be used as the threshold voltage. useful for making a pwm squarewave or various other patches. both circuits have hysteresis controls to clean up the output a bit.

both of the above circuits are run from plus and minus 12 volts. the 3k9 pull up resistor means the output swings rail to rail, so it can trigger either of the 2 vco designs (one syncs on a -12 volt spike, the other on a +12) with ease.
cheers
s/p

new stuff

hello.
ive been away from teh internetz for a while. but i have been busy. looky---->

i played a gig, which prompted me to not sleep and solder alot in order to have something worth showing. so the synth is now way bigger. 6 oscillators, mixer, rgb and sync interface, dual comparators and a freshly finished cabinet. and an ms10, all sitting on top of my old diy audio modular. and a bloody great big TV. and a camera. it was at the Vanguard Exhibition in East London, and was it was a great experience. im hoping to get some video from the gig soon, but otherwise here are some stills from some recent home jams:




fractal feedback

comparators and camera feedback:

and some straight RGB mixing of waveforms:

the comparator module is new, and great fun. im still tweaking it, but i hope to have it finished and a schematic up soon. also i have just completed the RGB and Sync interface module, which also needs a bit of work. lots of bleed due to unshielded 'done in a hurry due to impending gig' wiring. doh.
be seeing you
s/p