Back then...this is what we did...

[TheHermit]

It=laser shows, planetarium laser shows...

Thanks for clarifying. I've learned the importance of ensuring that we're on the same gig, before shooting off my mouth about the best effects and choreography to use ;-)
"Everything depends upon everything else."

Hmm, "I see piccolos as light hues and tubas in dark purples"...there might be a song there.

Horns are warm oranges,
electric guitar solo is a thin, sleak, lead cycloid with color mod,
sequential synth rhythms are fine webbed cycloids with blanking or beam zap sequences for stage gigs,
backing choruses and orchestras are diff pairs,
a kick beat is an AM ramp or ADSR trigger
mirror ball on the cymbal crash.
Projected imagery? Fog bad.
Spatial beams and scans? Good fog.

easy peasy.
😎

[Greg]

Oh hell yes! One of my greatest complaints about stuff I've seen is when bad music just continues on in mind numbing repetition, but the laser imagery changes multiple times with no excuse at all. I'm not suggesting the laser part should match the mind numbing music - pick different music! And don't think that cycloid development means changing to a new cycloid each measure. And for God sake get get a joystick. And Greg's RGB TO RYGB colormod, there's some real potential for artistry there...

There is wiring charts for this too if needed.

[lasermaster1977]

There is wiring charts for this too if needed.

Thanks Greg, and thanks to laserist for mentioning it. Very cool circuit.

This looks more like a RYGB to RGB colormod to me. (I'm not trying to be nit picky)

[laserist]

;-)……...................

[TheHermit]

There is wiring charts for this too if needed.

Thanks Greg.
I'm only just getting my head wrapped around using op amps and have overcome my phobia of designing my own circuit variations. Just completed testing a TL084 quad op amp circuit for RGB laser diodes (+?). It has single-ended outputs, 0 to +5 V p-p, because that's what I've seen others doing. So, I'm wondering why your schematic has differential outputs.🤔

Also, I've just received the OPA188 auto-offset-centering op amps that you previously suggested and will start breadboarding a prototype tomorrow for the single-ended bipolar x/y signals. My DAC outputs are 0 to +3 V p-p, so I've tested the TL084 with a 1k ohm resistance (Ri) and a 5k trimpot set @ 3.8k for feedback resistance (Rf). With offset correction, that provides an output of -6V to +6V p-p.
Am I correct in assuming that the gain of the OPA188 is still Rf/Ri? The circuit you showed had no Ri. It also shows Rref connected to the DAC, which my DACs don't require. Should I simply eliminate the resistor and DAC connection?
Thanks for your guidance.
Also, thanks to Lasermaster1977 for encouraging me to learn Kicad. Watched the 1st 2 lessons of John's Basement tutorials, skipped ahead to #9 to learn how to import the Digikey libraries. Within only one day, I'm already 1/2 way finished with the schematic design and have started my github repo to share with folks. WooHoo!
😎

[laserist]

Greg has some of his op-amp configured as voltage followers. A handy circuit that doesn't invert the signal and has a huge input impedence. The huge input impedence is useful for buffering potentiometers among other things. Any wiper based noise due to additional resistance at the wiper is minimized by the op-amp's huge input impedence.

The output of an op-amp simply tries the bring the two inputs to the same voltage. Circuits constructed with op-amp's can be really simple for laser shows because our images signals are relatively low frequency.

[laserist]

You might want to be careful using low resistances for your input and feedback resistors. Typically op-amp's have a pretty low max output current.

[TheHermit]

You might want to be careful using low resistances for your input and feedback resistors. Typically op-amp's have a pretty low max output current.

Oh yeah, I've heard something about math being important. Reckon I'd better try it sometime soon & figger out how much juice is flowin, before ordering PCBs. I'll probably need to fetch my pencil sharpener and the big eraser before tackling that-un. Now, where did I leave the dang ole slide rule?
Perhaps that explains the slight noise I'm starting to see at the peaks of the signals. I've only been copying others' circuits, then adjusting resistances to achieve the desired gain and offsets.
Thanks for the warning, Laserist.😎
But, what's up with Greg's circuit driving LDs with differential signals?
🤔

[laserist]

I believe the idea is to output RYGB colormod to an ILDA RGB projector rather than build a custom projector from scratch.

[TheHermit]

I believe the idea is to output RYGB colormod to an ILDA RGB projector rather than build a custom projector from scratch.

Ahh.. I see (said the blind man). Are ILDA standards for +/- differential RGB signals still a thing, for noise suppression on long cable runs, but only the + side is used on the LD driver board's inputs, with common grounds for RGB?
Thanks again for the hand-holding, guys. I'm getting there, but still playing ketchup.