Doepfer

Hi Mickey

I am coming back to your question regarding a Delay for CVs.
>> Dumb question.. What is a simple way to delay a control voltage?  say 
>> I have a CV coming in from a source (analog sequencer) and it feeds to 
>> an OSC, and I wish to delay the same CV and feed it to another OSC.. 
>> Any idea>>?

I wrote then:
> I could imagine a patch consisting of two S&H Modules, CV-Switches and 
> some digital control (Flipflop that switches between the S&Hs). This is 
> not really a final thought, but I think it should work. But(!): this 
> won't delay any continous CV-changes.

Then I wrote a message with an patch suggestion, that assuminlgy never
left my computer (I did not find it at yahoo). I tried it yesterday and
could refine it to the following setup:


Gate -------+-----------+
             |           |
             |          1/2  <- this is a divider
             |           |
             o           |
            / <----------+   <- this is a VC-switch
        +--o   o-+       |
        |        |       |
  CV-+------+--------+   |
     |  |   |    |   |   |
     |  +->S&H1  +->S&H2 |
     |      |        |   |
     |      +--o   o-+   |
     |            /<-----+   <- this is a VC-switch
     |           o
     |           |
     |        Quantizer
     |           |
    VCO1        VCO2


The basic idea is:
S&H1 stores the actual CV while VCO2 is controlled by S&H2 (the first
step will be something uncontrollable...). The next gate causes the
divider to toggle. The toggle switches the VCO2 to the S&H1 out and
stores the CV of the second step in S&H2.
Next gate toggles the divider. VCO2 gets again S&H2 and S&H1 is loaded.
And so on...

The Quantizer before the VCO2 is required, at least for the use with an
old A150. The problem is, that the A150 (VC-Switch) has a lot of
influence on the CV. I think it is cuased by the CD4053 CMOS-Switch,
which is used by the old  version of the A150. This has still a 100 Ohm
resistance when closed.

I don't know whether the new version of the A-150 (with DG-409 instead
of CD4053) makes the Quantizer obsolete.

The patch itself works really fine. If you play a single line of
harmonic steps you get nice chords.
The patch could be extended assumingly to an two-Note arpeggiator by
adding an A-156 with harmonic quantizing at the CV-Input of the whole
patch, which is fed by a triangle or saw from a LFO.




Florian