[english] [CS-80]: need an opinion from a skilled expert

Dieses Thema im Forum "Analog" wurde erstellt von omissis, 24. Dezember 2006.

  1. omissis

    omissis Tach

    Hi all, first post here, and have you all a Merry Christmas

    I'd like to get any answer from an expert about something going on the CS80 and every other CS synthesizer but it's not often recognized: there's a sort of continuous tracking from the vco to both the filters, these tend to lower the cutoff in sync with the pitch: you can notice that especially if you have a resonating sound and bend down with the ribbon to 0 Hz or next; by the way this is not connecte with keyboard tracking at all; does anybody know why this happens or can anybody point me to somebody who can giveme explainations??
    Thx a lot
     
  2. Moogulator

    Moogulator Admin

    :hallo:
    Hi, hmm I am not sure if I understood it correctly,..
    sync?
    we are talking about each channels VCO .. ok, but 0 Hz?
    what?
     
  3. Britzel!

    Britzel! Tach

    No i think what he wants to tell us with sync is just, that he noticed, that the Pitch of the OSCs affects the Cutoff frequency. (so nothing to do with syncing oscs to each other or something..)
    So for low notes the Cutoff is lower than for high frequencies. So like a cutoff follower. Am i right omissis? :)
     
  4. omissis

    omissis Tach

    yes, you are, Britzel! I know the CS synths so well and have made some tests with Synthedit which seem to confirm my speculation , I only would like to know if anybody who has technical skill or could read the diagrams well could share my thought, if is this really, the CV determining the pitch (which is shared also by the ribbon controller and the key tracking circuitry ) affects even the filters' cutoff. This effect is of course shared by each single voice card among the 4/8/16 avaliable respectively on the CS50/60/80. What I seem to understand is this: the KBC board ( coder from the Keyboard ASsigner) sends a CV to the voice card; this CV is sent at the same time to the HPF and LPF filters, so I should end up that there *is* a following....now I need someone to tell me that I'm not crazy!
     
  5. eminent

    eminent Tach

    I'm not an expert, but looking at the diagram you can see that at the "K" (Key) input of the voicecards, the Key-voltage, goes to the vco but also to both vcf-chips. These chips have an "KV" input too ! The manual says:
    "in order to change the tone color according to the tone range of keyboard, the degignated voltage of the key will supplied to the pin (0.25-4.0V)"

    The signal from the ribbon is decoded by the DA-convertor on the KAS-board, just like the keyboard, so it has the same affect. In other words: the ribbon-voltage is part of the "K" signal.

    The other source for the pitch ("V") at the voiceboards is fed only to the vco and not the vcf. Voltages for "V" come from the LFO, initial pitchbend and detune-slider. They don't affect the cutoff frequency.
     
  6. omissis

    omissis Tach

    :lieb: :kussi:

    thx Eminent, I'm not crazy!!! And, too bad, Arturia didn't emulate this on the V so it's far more incomplete than what I was expecting; the V still misses it as it misses a proper KAS arrangement, as well as the "expression circuit", as well as the phasing effect on the chorus, as well as a decent ringmodulator with the typical overdrive effect at full depth..... :toktok: :pckill:
     
  7. Britzel!

    Britzel! Tach

    any chance that some1 posts that diagram in here? :) i am really interested in that stuff :cool: .
     
  8. omissis

    omissis Tach

  9. Britzel!

    Britzel! Tach

    wow, thx a lot :).

    Let's see if my electronic knowledge reachs far enough to read that ;-).
     
  10. omissis

    omissis Tach

    Excuse me , eminent, what manual and where did you find that info on KV voltage, is it the User manual or the Service manual?
     
  11. Feinstrom

    Feinstrom aktiv

    Where is ppg360 when you need him most? :D ?
     
  12. omissis

    omissis Tach

    heh, Stephen runs a galaxy away from me when he reads my name 'cause he knows I'm a CS80 maniac ;-)
     
  13. eminent

    eminent Tach

    It's in the service manual, page42
     

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