Rebuilding my old analog console

[Kevint]

It a slight variation to that one. It's on page 14. Ronhip posed an attachment of the FXCY schematic - very helpful. The fixed quadrature oscillator section is in the upper left of the drawing.

[lasermaster1977]

It a slight variation to that one. It's on page 14. Ronhip posed an attachment of the FXCY schematic - very helpful. The fixed quadrature oscillator section is in the upper left of the drawing.

Ah ha, found it. It is quite similar to this one from Walter Jung's "IC op-amp Cookbook" here:



Thanks @Kevint

[Kevint]

Lasermaster1977: Exactly. Somewhere in another post, I think I saw a Texas Instruments version. I believe it was from their data sheets.

Thanks for posting the cookbook version.

[Kevint]

The AD633's will be here Wednesday, and I'll attemped to build the AM modulation circuit but I still need to get help with what to use for the envelope generator portion of the circuit.

[Greg]

I still need to get help with what to use for the envelope generator portion of the circuit.

I would suggest that the ramp generator you are looking for is in the CYGN-A schematic. The CYGN-A is a bank of three oscillators exactly like the one you built from the FXCY schematic, except their frequency is set by hard to get ganged pots instead of fixed value resistors. But there is also the ramp generator section of the schematic. Most of the schematics I have came from Ron's archive. Ron seems to have a way of evaluating when and to whom information from the archive is bestowed.

[laserist]

...when and to whom information from the archive is bestowed.

I'll take a guess:
The when is simply when someone is ready to use it. The whom is someone who isn't an asshole.

[Kevint]

Thanks Greg. For this effect I think I'm looking for some type of adjustable sawtooth wave to drive the AM (I'm guessing 0.1Hz to 2Hz range). There's a Laserium video where the image grows from nothing to a given size and either disappears or holds. I see that there is blanking going on but I can tackle that latter. Really trying to see if I can get independent master XY AM gain working. Here is the video clip.

https://youtu.be/NLWL1YQ8DNo?si=2Nn3IcSK6mYaQjy2

From the discussion on page 10, it looks like the AD633s would do this given the proper envelope signal. Laserist mentioned the signal comes from the 351 data. I'm hoping for an analog solution if possible. Here the drawings posted by Laserist. A5 - A8 are the AD633s that do the AM stuff to the selected input signal is my understanding. Also, back in one of the CYGN discussions was the colormod II and there was a scope picure showing an adjustable sawtooth wave and I thought that would be a good starting point. Let me know if I am totally off my rocker.

[Kevint]

Laserist: truly hoping I'm not in the second category.

I bought a signal generator . Never owned one before. I'm thinking I can play around with different wave forms as the AM signal for the AD633s.

[DZ]

Not sure if you'd be interested but I have a couple unpopulated boards that would handle AM quite well. The first has a pair of LFO's that outputs triangle and square. With a symmetry pot the square wave goes from 1% to 99% duty and the triangle goes from leading edge to falling edge ramp. The other board has 3 dual channel VCA's. These aren't using multipliers IC's, instead it's using a transconductance amp, the CA3080. A bit hard to find the CA3080's but they're out there. Synthcube.com usually has them.

[Kevint]

DZ: Thanks for the offer. What's the frequency range of the envelope generator of the AM? Can it go down to 0.1Hz for a very slow ramp?