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Thread: WANTED - DAC for 15k scanner

  1. #21
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    Mecheng3;

    I haven't seen any testing done with anything other than the Mamba Black and Easylase USB combination. (Well, and the Pangolin setup of course.) However, I can't see how a change is software is going to solve a hardware problem. The DAC should be able to output points at consistent intervals regardless of the software. (The key is that on a USB DAC the timing signal that controls the point output speed is generated locally on the DAC and not slaved to the computer's clock like it would be with a parallel port DAC.)

    To test the EasyLase DAC, we loaded up the ILDA test pattern and hooked up an oscilloscope to the X output of the DAC. On the scope you could clearly see the wave shifting from side to side. It was especially easy to see when we zoomed in on the large square wave that is just past the middle part of the pattern. The trailing edge (vertical section) of that square wave would move from side to side on the 'scope. This would manifest in the test pattern as a blurring or slight trembling of the pattern from side to side.

    When we hooked up the Pangolin board, the problem went away. (Still using the same scanners and amps.)

    Damn - I wish I had thought to take a picture of the 'scope when we were doing all this... ops: Would have made it a lot easier to explain. (D'oh!) I'll try to remember that in the future. (sorry...)

    It would have been nice to be able to test other DACs (notably, the JMlaser USB DAC that Jimbo was asking about), but we didn't have one at FLEM to play with. Also, no one at FLEM was running the LDS software, though honestly I don't think it would have made any difference. (see above)

    Don't get me wrong; the effect was subtle and only really manifested itself when we looked closely at certain portions of the test pattern. When displaying shows, you would probably never recognize that there was a problem. But when looking at the static test pattern, you could tell that something was wrong.

    Bill immediately identified it for what it was (sample jitter), but he had to hook up my oscilloscope before the rest of us fully understood his explanation. (Well, I think some of the more experienced guys (Dzurcher, Clandestiny, etc) also had it figured out right from the begining, but I know that *I* didn't truely understand what was going on until I saw the output on my 'scope.) It was about then that Fred has his "I feel like taking a hammer to my DAC now" moment...

    Adam

  2. #22
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    sample jitter
    Yeah, I know what that is... I get it every morning before I have my coffee.

    David

  3. #23
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    Hi ANDY ....

    If you have really made up your mind on an alphalite Pro .... go for it .... i can recomend it as it was one of my first intros to software
    and Rick who wrote the software is very helpful and it is a great stepping stone to pangolin


    If you are interested i can sell you my Alphalite Custom system ..... and software

    This is a complete 19" rack mounted alphalite unit that also has the PSU built in
    the Enclosure also Contains a Chameleon Geometric converter
    ( which allows you to put the projector in any position and still have a perfect image say you could only put the projector high up in a corner of the room
    the coverter will allow adjustments to the image to project a perfect square on a centre screen )
    and also a 4 way source selector ( which allows to to switch the projector to other control signals ... say if you get a pangolin in the future )

    The alphalite Pro unit is the second 19" rack from the bottom ( a 2U ) in the flightcase
    and just to clarify the flight case, lasergrafix desk and switch panel are not included ....

    Just the middle 19" rack whch contains
    Alphalite Pro DAC
    Chameleon Geometric converter
    power supply (internal) for alphalite and Geometric
    4 way ILDA signal switching unit ( 4 ILDA inputs and 1 Projector output )
    All 25 way Cables ( PC paralell and ILDA )
    240v Mains cable
    and all my copies of Alphalite software and ILDA frames


    and nothing else

    http://www.esnips.com/imageable/medi...c-63b27ea041a8

    http://www.esnips.com/imageable/medi...f-c1e8adad84ca


    some bigger photos here .....
    http://www.esnips.com/webfolder/f133...5-bc1894caa66f
    Im willing to sell for £200 + Postage (The geometric corrector cost over £500 on its own so the whole thing has a value of about (£900)


    all the best .... Karl

  4. #24
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    Quote Originally Posted by Banthai
    Hi ANDY ....

    If you have really made up your mind on an alphalite Pro .... go for it .... i can recomend it as it was one of my first intros to software
    and Rick who wrote the software is very helpful and it is a great stepping stone to pangolin


    If you are interested i can sell you my Alphalite Custom system ..... and software

    This is a complete 19" rack mounted alphalite unit that also has the PSU built in
    the Enclosure also Contains a Chameleon Geometric converter
    ( which allows you to put the projector in any position and still have a perfect immage )
    and also a 4 way source selector ( which allows to to switch the projector to other control signals ... say if you get a pangolin in the future )

    The alphalite Pro unit is the second 19" rack from the bottom ( a 2U ) in the flightcase

    http://www.esnips.com/imageable/medi...c-63b27ea041a8

    http://www.esnips.com/imageable/medi...f-c1e8adad84ca


    some bigger photos here .....
    http://www.esnips.com/webfolder/f133...5-bc1894caa66f
    Im willing to sell for £200 (The geometric corrector cost over £500 on its own so the whole thing has a value of about (£900)


    all the best .... Karl
    wow that looks a beast...
    one problem, ive no idea what you said or what it is LOL. I know nothing about DAC's could you explain again in simple terms for a simple person???
    Eat Sleep Lase Repeat

  5. #25
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    Hi andy

    have added some more details to my above post ....

    I have had a couple of PMs requesting if i can ship this unit to the states .... But this unit has a 240 V transformer fitted internaly
    and wont run in the US unless you rep-lace it with a 110V unit

    also to clarify a question that someone asked ..... The laptop, the Lasergrafix desk and the switch panel is not included

    Just this Bit .....

    http://www.esnips.com/doc/c05d541d-f...259/laserrig6a

  6. #26
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    i cant view that pic, as i need to sign up.

    im very interested, but need to hold off for a week or so, if thats ok. im being sent the dac so let me see how it is
    Eat Sleep Lase Repeat

  7. #27
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    Hey Karl;

    What is that top rack for? Looks like some kind of Live control board... With maybe some scaling/position controls on the right, and maybe a sequencer/chaser and a speed control? Did you have it made custom for you, or is that an actual retail product? Either way, it looks cool.

    As for the middle rack with all the geometry controls - all I can say is WOW! Very cool. No way the Alphalite came with all that extra hardware!

    Adam

  8. #28
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    Dec 2006
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    im getting stresed now, got the alpha dac but cant get it to work, it might be my setup.

    I may have to spend more money than i want to here, is the easylase USB and HE-Scan software any good???
    Eat Sleep Lase Repeat

  9. #29
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    Andy, open a thread in the Lounge and I'm sure you will get help on setting up and running the Alphalite.

    Jim

  10. #30
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    ok cheers
    Eat Sleep Lase Repeat

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