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Thread: CYGN-B

  1. #261
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    Quote Originally Posted by Greg View Post
    I certainly noticed those (photo). They're in a bank vault for now.

    I figure might as well make the colormod2 signal available to the axis summing input of the CYGN-B. Attached schematic shows the plan for this.
    The six buttons over the beam torquer knob on the Mark 6 control panel selected the CYGN-A Osc 1, Osc 2, Osc 3, Spiral ramp, and color mod 2 ramp to the color mod 2 gain control. The last switch ( as I recall) killed the color mod 2 output and shunted it into the color mod 1 Vco input for frequency modulation of color mod 1.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  2. #262
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    Default 2QMM photo

    Hey, Brian,

    I've never seen one of these unpotted. I'll add the photo to the archive. I think I still have a few of these around somewhere in my Laserium detritus.

    Ron

    Quote Originally Posted by laserist View Post
    The spiral, multiplier, multiplier summing, multiplexer multiplier, and fixed cycloid boards all used a two quadrant multiplier module that Laser Images designed. I assume they went to the trouble because the AD533's they used on the audio mod board needed three trim pots, were a pain to adjust, and took up a fair amount of board space. All in all Ad532's at $25 each in 1980 dollars always seemed a better choice. Today the AD633 is even more economical.
    Attachment 57309
    Last edited by ronhip; 11-22-2020 at 11:40.

  3. #263
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    Brian,

    I remember, as you do, that the 6th button for CM2 applied FM to CM1. I believe the source for the FM signal was either the sum of the CYGN-A or just the C oscillator of CYGN-A. Hard to remember these details after 22 years NOT performing shows! The wiring may be in the blue-binder.

    I always thought it was a shame they never provided a way to do AM of CM1 (except with the potentiometer). We missed out on many interesting looks.

    Ron

    Quote Originally Posted by laserist View Post
    The six buttons over the beam torquer knob on the Mark 6 control panel selected the CYGN-A Osc 1, Osc 2, Osc 3, Spiral ramp, and color mod 2 ramp to the color mod 2 gain control. The last switch ( as I recall) killed the color mod 2 output and shunted it into the color mod 1 Vco input for frequency modulation of color mod 1.

  4. #264
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    Quote Originally Posted by laserist View Post
    The six buttons over the beam torquer knob on the Mark 6 control panel selected the CYGN-A Osc 1, Osc 2, Osc 3, Spiral ramp, and color mod 2 ramp to the color mod 2 gain control. The last switch ( as I recall) killed the color mod 2 output and shunted it into the color mod 1 Vco input for frequency modulation of color mod 1.
    That's good to know, thanks. Even without regard to function, those iconic illuminated buttons may be the most attractive element to appear on any control desk.

    Other News:
    With fresh gratitude to the small group of elite contributors (of knowledge and hardware), I can announce that I have had my first look at another magnificent schematic of a classic Mark 6b module. And related to that, apologies if I am re-starting a discussion that has occurred elsewhere, but there seem to be a couple of vendors whose sites say that while the Burr Brown 4302 is discontinued, it is in stock and available. I have requests in to follow up on this.
    Attached Thumbnails Attached Thumbnails six_buttons.jpg  

    bb4302.jpg  


  5. #265
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    Quote Originally Posted by Greg View Post
    That's good to know, thanks. Even without regard to function, those iconic illuminated buttons may be the most attractive element to appear on any control desk.

    Other News:
    With fresh gratitude to the small group of elite contributors (of knowledge and hardware), I can announce that I have had my first look at another magnificent schematic of a classic Mark 6b module. And related to that, apologies if I am re-starting a discussion that has occurred elsewhere, but there seem to be a couple of vendors whose sites say that while the Burr Brown 4302 is discontinued, it is in stock and available. I have requests in to follow up on this.
    There was exactly one 4302 in the Mark 6. It was one of the mods that were done over the years. It was a ramp shaper for the spiral ramp signal. I didn't like the shaped look and almost always kept the control at 5 to yeald a linear look. I have one of them, I'll put it in the next shipment...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  6. #266
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    Quote Originally Posted by ronhip View Post
    Brian,

    I remember, as you do, that the 6th button for CM2 applied FM to CM1. I believe the source for the FM signal was either the sum of the CYGN-A or just the C oscillator of CYGN-A. Hard to remember these details after 22 years NOT performing shows! The wiring may be in the blue-binder.

    I always thought it was a shame they never provided a way to do AM of CM1 (except with the potentiometer). We missed out on many interesting looks.

    Ron
    I think color mod 2 was bipolar so amplitude modulation would have been interesting. With a 4qmm you could either modulate with the reversal or put a precision rectifier in the signal path. I want to build a box to do laserium style color mod slash chopper with The Radiator - I'll post it when and if...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  7. #267
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    The sillyscope agrees: color mod 2 is bipolar. Do I understand correctly from previous posts that that the 4QMM is either AD533 or AD532 chips, and the 2QMM is a two quadrant multiplier module that Laser Images designed?

    I'm going to post a discussion found online that mentions the AD
    811 and AD821, and gets all the way to an interesting technical gripe about a mission to another planet.

  8. #268
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    D841 or AD811
    « on: October 12, 2007, 10:21:54 PM »
    Anybody know what an AD841 or an AD811 is? I'm trying to figure out some pre-amps that use these. They are 6 legged devices looking like a small transistor. The power supplied is positive only, 15V. I thought maybe they were dual transistors but my transistor checker refused to identify them.


    « Reply #1 on: October 12, 2007, 10:36:53 PM »
    I'm pretty sure I'm reading these numbers right. They are pretty old devices with a datecode of 1980 if I read that right. Silver can with goldplated legs. I know the 841 gets pos 15V. The 811 I'm still trying to figure out. They are in little modules that slide into a rackmount unit so it is rather hard to trace them with power applied.


    « Reply #2 on: October 12, 2007, 11:51:29 PM »
    I believe the 841 is a dual N-channel JFET, and certainly the AD811 you mention in a six-lead TO- case is a dual PNP. I used both of them around that date code time. AD ran out of part numbers, got out of the discrete business for the most part (except for the acquisition of PMI) and figured no one would care...


    « Reply #3 on: October 13, 2007, 12:45:09 AM »
    I did a search on dual N-channel JFET and came up with a LS841 at Linear Systems. They didn't have anything that was 811, but another module, I have 16 of them, has a MP311 in that position. LS has a 311 that is a dual NPN. What do you think? Are they the same things?


    « Reply #4 on: October 13, 2007, 04:14:22 AM »
    Wait I think you might be right about the 811 being a dual NPN. The AD821 was the PNP now that my memory is jogged.


    The AD840 at least was the dual FET I think, probably the 841 too. It was well-matched, medium voltage, not too much low-frequency noise, but otherwise unremarkable.


    Although I don't think I have any of the FETs I might have some of the 811s and could determine the pinout and see if it corresponds to the Linear Integrated Systems parts.


    EDIT: Yes LIS gives the LS840, 841, and 842 as subs for the AD parts, and the datasheet looks about as I remember, with things being characterized at 200uA.


    Also LIS gives the LS311 as the sub for the AD811, and it is indeed an NPN dual: http://www.linearsystems.com/datasheets/LS310-3.pdf


    « Reply #5 on: October 13, 2007, 01:15:56 PM »
    Quote from: "mediatechnology"
    OK, I'm pretty sure that I have an older Analog Devices data catalog that would have these. Let me look for them. Didn't realize that they re-used part numbers...


    Yes, I wonder whose decision that was. It does make things very confusing.


    They were quite high on their discretes during that period (circa 1973 btw), with the typical our excreta don't stink attitude of AD of the period. Before I began to understand how FETs really worked I bought it too---there's an embarrassing gush I penned in the middle of an NSF proposal for a silicon target vidicon areal photometer where I extol the supposed virtues of the AD840 for a preamp. I also talk about the configuration of using half of it as an active drain load (less commonly seen than the source follower configuration, with half as the lower current sink) and make the very wrong assertion that it only has the voltage noise of a single device ops: .


    Well, we didn't get the money, not because of that blunder, but mostly because of political naïveté. But it was probably as well, since not too long after a sharp guy did a really good analysis, supported by experiment, of how truly lousy the vidicon was---that its readout noise was horribly worse than almost any preamp's*. By then a stopgap instrument was underway using a linear photodiode array. When that system was finally working guess what?---the intrinsic detector noise was again much larger than the preamp's. See a pattern? But I had fun, learned a lot, and some science was finally done.




    *When I met the outspoken Andy Young at Table Mountain Observatory, I mentioned a paper of his about the vidicon photometry from one of the Mariner missions to Mars, in which he compares the quality unfavorably to some stellar photometry with gas-filled photodiodes in 1914. He laughed and said "Ahh that's the paper that got me fired from JPL!!"


    One of the problems was that the innards of the vidicons got perturbed inelastically on takeoff, which screwed up the lab calibrations; another was spacecraft system noise from power supplies that hadn't been adequately suppressed; and then the science team needed to show the public pretty pictures, and not do recalibrations.

  9. #269
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    Quote Originally Posted by Greg View Post
    The sillyscope agrees: color mod 2 is bipolar. Do I understand correctly from previous posts that that the 4QMM is either AD533 or AD532 chips, and the 2QMM is a two quadrant multiplier module that Laser Images designed?

    .

    I'm going to post a discussion found online that mentions the AD
    811 and AD821, and gets all the way to an interesting technical gripe about a mission to another planet.
    Yes, Laser Images used AD533 chips originally on the Mark 4, designed the 2QMM circuit and used it in many places, and built up the z axis rotators for the Mark 6 using AD532 chips
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  10. #270
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    Quote Originally Posted by Greg View Post
    The sillyscope agrees: color mod 2 is bipolar. Do I understand correctly from previous posts that that the 4QMM is either AD533 or AD532 chips, and the 2QMM is a two quadrant multiplier module that Laser Images designed?

    I'm going to post a discussion found online that mentions the AD
    811 and AD821, and gets all the way to an interesting technical gripe about a mission to another planet.
    I found this in a scan of an old Analog Devices newsletter:
    Click image for larger version. 

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    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

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