[sdiy] Dual VCO mixing. / first synth DIY project.

[cacofone]

Magnus,
Yes, sounds pretty clear :) Gonna get started on making some VCO's and go 
from there. I'll keep the sdiy list updated. I found a good VCO schematic 
on the Emusic DIY page that has  tri, sq, sine, and I think it also had 
ramp (might be wrong on the ramp) Can you suggest a VCO schematic that's 
versatile and not that terribly hard for a beginner, or is the one there 
recommended? I'd really like to have at least triangle, square, and I 
really want sine, even though I know, yes, tri/square are easiest, and 
perhaps I can add the sine in later after I've implemented square. I assume 
I'd start with square and get that to function, then add the triangle 
followed by sine.

Any advice is greatly appreciated.

I also assume that these can be compounded using the opamps to add more 
VCO's in the future? I've got a fairly large case that I'm intending to 
fill (used to be a tape deck cabinet), and this is my first DIY synth project.

I read somewhere to do the power supply first, though I've seen pre-made 
ones that are cheap, supposedly reliably, and wouldn't "waste" time. Any 
thoughts?

Can you or someone else elaborate a little more on what you mean by 
inverted? I assume the polarity (-/+) but if I wanted to re-invert it, how 
would I do so?

but I At 8/25/2001 06:32 AM, you wrote:
>From: cacofone <pulse8 at goodtimetribe.com>
>Subject: [AH] looking for schematic for dual vco
>Date: Sat, 25 Aug 2001 03:14:03 -0500
>
> > Hello, looking for a current (doesn't use CEM3340) Dual VCO, where I can
> > mix the VCO's (i.e. Pulse/triangle etc)
> >
> > Or, if I've got two VCO's, how do I mix the two? With an op-amp?
> >
> > looking for more details...
>
>This is really an Synth-DIY list question... but anyway:
>
>Take an op-amp. Hook the (+) input to the ground. Hook in a resistor
>(say 10k Ohm) between (-) input and the output. Connect your input
>signals through resistors (say 10k Ohm again) to the (-) input.
>This will give you a summing of the signals (VCOs or whatever) on the
>output. You should be aware that the signal is inverted, but maybe you
>don't care.
>
>If you want level controls, just damp the signals through pots and
>hook the tapper through the input resistors.
>
>Hope that came out clear.
>
>Cheers,
>Magnus

nKode / Pulse 8 / cacofone [aim:jkerseyVCSO]
Good Time Tribe / http://www.goodtimetribe.com
Dallas Regional Electronic Artists And Musicians 
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