Rebuilding my old analog console

[Kevint]

For the past weeks I have just been playing around with the circuits to see how things interact and what various waveforms do to the image. I'm hesitant to put anything together yet until all the pieces/effects are built. At that point put a plan together on how to attach things. I've gotten really good info from this forum on how others have done this and thank you for that.

Currently:
4423 oscillators work well
Fixed cycloids working well (does not include the PDM sigal)
Arduino driven solid state relay board for signal selection is demonstrated
KQO working well
AD633 as VCAs working for AM
Summing Amps working well
Scan amps are good enough for now

Next I would really like to add the SPGN effects (which I think includes Diamond Spirals and the offset Spiral tubes) . I know that Greg has done this on his threads, but it doesn't seem to be documented. Any support or guidance would be greatly appreciated.

[swamidog]

video, or it didn't happen... thems the rules!

For the past weeks I have just been playing around with the circuits to see how things interact and what various waveforms do to the image. I'm hesitant to put anything together yet until all the pieces/effects are built. At that point put a plan together on how to attach things. I've gotten really good info from this forum on how others have done this and thank you for that.

Currently:
4423 oscillators work well
Fixed cycloids working well (does not include the PDM sigal)
Arduino driven solid state relay board for signal selection is demonstrated
KQO working well
AD633 as VCAs working for AM
Summing Amps working well
Scan amps are good enough for now

Next I would really like to add the SPGN effects (which I think includes Diamond Spirals and the offset Spiral tubes) . I know that Greg has done this on his threads, but it doesn't seem to be documented. Any support or guidance would be greatly appreciated.

[laserist]

Laserium’s spiral used a nice little circuit that generated a linear waveform that would ramp up and ramp down at a rate determined by 0-10V signals called “in” and “out”. (Because that’s what the image does…) A third 0-10V signal called Sweep could be summed to either the x or y axis. (Not both at the same time.) As you approached max sweep the image on the axis the sweep is summed to clips as it hits the power supply rail until at Max sweep the only signal getting to the scanner is the sweep voltage ramping in and out by the spiral ramp. (The axis not getting the sweep is just spiraling with the ramp like normal). One of the nice features of the spiral ramp circuit was it could be reset to 0V, and then restart from 0v when the reset went away. Another feature was an inverse ramp. When reset the inverse ramp when high. Diamond spirals were simply the spiral ramp driving the multiplier on one axis and the inverse spiral ramp feeding the multiplier on the other axis. The Inverse spiral ramp is not just the spiral ramp inverted. These were 2 quadrant multipliers. The inverse spiral ramp was the spiral ramp inverted and then offset to put it on the right side of ground.

[Kevint]

Swamidog: good point. I'll put some short video clips and post some images. I'm doing this with my phone so the video quality is terrible but you will get the idea.

[Kevint]

Laserist: Thank you for taking the time for the detailed description. Very helpful. when the signal hits the voltage rails like you described, is that when the image looks like a D instead of a circle. I have seen the D shape image in some of the Laserium videos on YouTube.

[swamidog]

Swamidog: good point. I'll put some short video clips and post some images. I'm doing this with my phone so the video quality is terrible but you will get the idea.

awesome! thank you

[laserist]

Laserist: Thank you for taking the time for the detailed description. Very helpful. when the signal hits the voltage rails like you described, is that when the image looks like a D instead of a circle. I have seen the D shape image in some of the Laserium videos on YouTube.

If it's happening with an offset it could be a inv spiral in reset. Otherwise there was a clipper circuit that was added around Crystal Odyssey that the cycloids ran through. I never liked it, but I was pre-feedback scanners...

[Kevint]

Thank you. That makes sense.

[Greg]

Next I would really like to add the SPGN effects (which I think includes Diamond Spirals and the offset Spiral tubes) . I know that Greg has done this on his threads, but it doesn't seem to be documented.

You are correct much of the documentation does not appear on the threads. It's CYGN-A page 6 and on documenting when I was where you are. I put the KQO, an oscillator for an amplitude modulation source, AM using 4QMMs, and Brian's AD633 rotation circuit on one board in the 6B image generators rebuild. My own easily created with op amps and AD633s versions of sweep depth, sweep offset full +-10V for 4QMM, diamond, and direction controls, and image rotation, are all accessed through panel switches and and pots.

The SPGN as a whole features three analog and three digital control inputs which receive signals from the data track. Without the data track, having these inputs present in a system might serve little purpose, unless one were to undertake the task of creating something to take the place of the encoders. To my knowledge, the original encoders still exist and do function.

My version of the SPGN resettable ramp generator exists having been liberated from the rest of the functioning of the SPGN. This circuit receives IN and OUT control voltages, and a two bit reset signal for an added feature that was not accessible in the original.

This circuit provides ramp and PDM to the computer systems. All the functions of the spiral generator are then implemented in software. Keep in mind this means most of the functions are duplicated, the digital set downstream from the analog set. This expands the image generating capabilities of the system.

I have built the SPGN on breadboard twice. There are some difficulties involved in building this circuit. The most significant being that the 2QMM units need to be substituted with an equivalent circuit. Brian stated an equivalent circuit using the AD633. I eventually got every function of the SPGN working, but the "D" shaped clipping was present which, until now, I didn't know was a feature rather than being bugs in my version. I'm almost certain there were bugs, as I recall there was some asymmetry in the clipping, or some similar kind of distortion that didn't look right. It made sense to me at that point to do all the deterministic things in software. This was rapidly accomplished and has given the expected results plus any performance variations one seeks.

[Kevint]

Greg. That is a ton of work you have done and I'm at the beginning stages like you were. My goal for this project is to just create a mostly manual analog system with the help of a arduino to provide signal switching - pushing 1 button activates multiple things. It sounds like it is possible to build the SPGN functionality but is it possible to get circuit details?