OldSynths

hi all,
i have a moog source with a control voltage input (CV), but i'm not 
really familiar with what it does and how it works.
i understand you can feed a signal in to the CV input, and somehow 
control the synth.

what kind of signal should be fed in to the CV-input(any audio 
signal??), and which parameters(pitch only??) are controllable with 
the signal?

thanks for any help!

/einar

To put it simply, synthesizers work with a one volt per octabe change.Adjust accordingly, whether you are feeding a solid voltage, an audio voltage, or some kind of a ramp. The control voltage will change accordingly.
 
Bonnie *:>

Einar_Ekstr\ufffdm <einarekstrom@...> wrote:
hi all,
i have a moog source with a control voltage input (CV), but i'm not 
really familiar with what it does and how it works.
i understand you can feed a signal in to the CV input, and somehow 
control the synth.

what kind of signal should be fed in to the CV-input(any audio 
signal??), and which parameters(pitch only??) are controllable with 
the signal?

thanks for any help!

/einar  


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Thanks for your replies, now I understand the CV thing a lot better, 
even though there was a lot to digest. :-)

The reason I ask this question is I'm doing some home recordings 
with my laptop, using Cool Edit Pro, and what I would like to 
acomplish would be to control the synth with one of the drum tracks. 

So, if I understood everything correctly: I could use the audio 
signal from the snaredrum, for example, to control the pitch of the 
synth. Because I'm using a drum machine, the amplitude of the single 
drum track should be very consistent, therefore the resulting sounds 
from the synth should be equally consistent.

I'm pretty sure the CV input is routed to pitch, since there's no 
indication of what it does, nor is there any routing possibilities.

Thanks,
Einar

Hi Einar and list .
I would add to Bonnies explanation .
vintage synthesizers (and most of the new analog ones) are having voltage
control inputs to able the user to control the parameters using external
devices , such devices can be analog sequencers , midi>cv converter ,
voltage quantizer or a CV keyboard .
some of this CV inputs are 1V/Oct and are used for controlling the
pitch/tune of the synthesizer as Bonnie had explain . usually you would want
to connect a controller that would generate this 1V/Oct format such as a
quantizer module or midi>cv .
other CV inputs that are not using the 1V/Oct format can be control by any
voltage source in order for example to control Frequency/cut-off of a VCF ,
PWM etc .
connecting audio in to the 1V/Oct would make an exponential FM of your VCOs
, nice sounds (-:

Hope that help .

Cheers
Gur Milstein
ANALOGIC Analog Control System
http://www.analogic-acs.com

----- Original Message -----

From: "Einar Ekstr\ufffdm" <einarekstrom@...>
To: <oldsynths@yahoogroups.com>
Sent: ??? ????? 19 ?????? 2003 16:18
Subject: [oldsynths] control voltage question


> hi all,
> i have a moog source with a control voltage input (CV), but i'm not
> really familiar with what it does and how it works.
> i understand you can feed a signal in to the CV input, and somehow
> control the synth.
>
> what kind of signal should be fed in to the CV-input(any audio
> signal??), and which parameters(pitch only??) are controllable with
> the signal?
>
> thanks for any help!
>
> /einar
>
>
>
> To unsubscribe from this group, send an email to:
> oldsynths-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>

Okay, I've been wondering about bipolar CV... I built a joystick 
controller for someone's Analogue Solutions modular, and I built it 
to have -9v/+9v outputs. When I was building it, I'd heard they used 
0-6v, then I heard 0-12v, and then -6/+6v. Not knowing for sure, I 
contacted the manufacturer, and they said the modules were 
controlled -10V/+10V, bipolar. From the hoarse's mouth......

I guess I didn't quite understand. I built the joystick to run off 2 
9v batteries, and calibrated the center X/Y positions to 0v. Left = -
9v, Right = +9v, same with Up/Down. I sent each voltage to an 
individual output. So there were 4 outputs total (-9, +9, -9, +9).

When I got done and sold it to him, only the + voltages worked. The - 
voltages had no effect on any module.

But it worked great, so there was no issue. Just redundant outputs!

The only thing I could think was maybe the CV inputs had stereo 
jacks? +/-/ground?? That seemed wrong though.

Can anyone explain bipolar CV?

Thanks,
-Mike Walters
www.mysterycircuits.com

> Can anyone explain bipolar CV?

Bipolar CVs are used in most modular systems. But it maybe that the
module in question does not respond to negative (-ve) inputs. Most VCAs
tend to work only with +ve input voltages. However, a negative input
voltage is also a good thing if your VCA has a gain bias (or initial
gain) control. Turn this pot up to half way, and your bipolar input CV
will now open and close the VCA.

A VCF and VCO will happily run with both -ve and +ve inputs. -ve inputs
will control the module's parameter downwards, and +ve ones upwards. So
a VCF's cut-off frequency will move downwards with increasing -ve CV.
But you will of course have to have set the VCF's cut-off to a point
where it can move downwards. If its already at its minimum, it probably
can't go any lower.

But I am puzzled by the fact that your unit had four outputs. Normally
one would expect just two outputs, X and Y. Both outputs would usually
be allowed to go either +ve or -ve.

Regards,

Tony Allgood                       Penrith, Cumbria, England

Oakley Sound Systems                   www.oakleysound.co.uk
Modular Synthesisers      www.oakleysound.co.uk/projects.htm

> But I am puzzled by the fact that your unit had four outputs. 
Normally
> one would expect just two outputs, X and Y. Both outputs would 
usually
> be allowed to go either +ve or -ve.


I can't remember... Looking now at the schematic, I originally 
intended just 2 outputs. I had a few issues once I had it built. I 
think when it just had 2 outputs, somehow it would combine to 0-18v. 
Then, I tried to send the + to one lug, and the - to the other, but 
then that caused problems grounding with the chassis. I think I may 
have just run out of ideas by then, and seperating them worked. Now, 
what's the simple solution? I know I'm going to kick myself...
-Mike Walters
www.mysterycircuits.com