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Lowrey Cotillion formant filter schematic

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  • tucsondave
    replied
    Here's the parts list.
    Operation in a nutshell:
    Audio in is a sawtooth wave from the keyers. Voltage controlled filters are varied by the voltage divider consisting of the resistors to 14 volt supply and the resistors that are connected to the PIC chips which connects them to ground as needed.

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  • andyg
    replied
    The Cotillion was maybe a little to far ahead of its time - with the result that it gained a reputation for unreliability. I don't think we're into sampled sounds here, AFAIK it's all done with filtering.

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  • tammynono
    replied
    andyg Thanks! I will check out that kawai. The Cotillion trick is really what im interested in. because i would like to
    A: do as you suggest and allow it settle on one sound
    B: give manual controls for the filter itself
    C: add a control voltage input so that the adjustments can be modulated by an external lfo

    Im not sure what the base oscillator for the choir sound is. Whether its just cycling through various states of the 3 filters @TusconDave posted in the schematic, or if there is some kind of a rom holding the various voice waveforms. It seems like everything between 1979 and 1985 was a hybrid of everything.

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  • andyg
    replied
    If you're just looking for analogue vocal sounds like OOH and AAH, it might also be worthwhile considering the electronics from the Kawai DX900 as well as the Cotillion.

    I remember our engineer at Kawai taking a brass sound from a Kawai E550 and filtering it into AAH. Not sure how he got the OOH, but he predated the Cotillion and DX900 by a year or two. Alas I have no idea exactly how he did it!

    The Cotillion's trick was to cycle through the various vocal sounds it could produce with each key press. Fun for five minutes but became irritating when you only wanted one sound to stick!

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  • tammynono
    replied
    At the risk of sounding like an Ingrate, do by chance also have the parts list so i can figure out those op amps?

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  • tammynono
    replied
    WOW thank you so much! I can't believe it. Thank you, Thank you!

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  • tucsondave
    replied
    Here's the filter schematic.

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  • tammynono
    started a topic Lowrey Cotillion formant filter schematic

    Lowrey Cotillion formant filter schematic

    Hiya,
    I am trying to build a eurorack module that approximates the Choir function on the cotillion D-575. I'm digging through patents etc. right now, but i was wondering if anyone had a cotillion schematic, or knew when that function first appeared in lowrey organs. I imagine its just some kind of poly formant filter, but being an early 80s thing, im not sure if theres a basic little processor in there with code or if its done with some CEM or SSM chips.
    So really any information about the early 80s Lowrey choir effect would be great! thanks so much to anyone who takes the time to respond.
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