vc wave select

[tomg]

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From: jorgen.bergfors at idg.se
To: vco at mindspring.com; synth-diy at mailhost.bpa.nl
Subject: Re: vc wave select
Date: Monday, March 29, 1999 1:24 AM

>The wave selector is not a true adc. I rearranged it so it would
>switch waves in the order I wanted. Ruins it for adc applications.
>But your 4532 idea might work fine on this version. I though
>somebody might be interested, so I converted it to a more
>proper adc.

Is this really such a clever idea? The Simonton 4 bit converter does the
same with just one IC (TL074) indead of three. It does need a bunch of
resistors, but they are easier to make a board layout for. It can be done
on a single sided PCB without wire links.

/Jorgen
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I think so! I guess it depends on how you want your waveforms to switch.
We'll assign waves like this saw-a pulse-b tri-c sine-d

Binary works like this....

a  b  c  d
-------------
0  0  0  0 
1  0  0  0 
0  1  0  0 
1  1  0  0 <- everything falls apart here if you want to turn your waves
                  on in sequence. 

My idea works like this.....

a  b  c  d
-------------
0  0  0  0 
1  0  0  0 
0  1  0  0 
0  0  1  0
0  0  0  1 <- everything in sequence, then the mixing starts 
                  first 2 wave combinations in sequence.
1  1  0  0
1  0  1  0
1  0  0  1
0  1  1  0
0  1  0  1
0  0  1  1 
1  1  1  0 <- then 3 wave combinations in sequence.
1  1  0  1
1  0  1  1
0  1  1  1
1  1  1  1<- and finally everything

Let's see you do that with a flash converter...If you are talking about
the adc it's just a little extra good luck life threw in. Kinda like
turning the Moog hi-pass into a phaser, I just looked beyond what 
was in front of me. Doesn't mean it's useful, just that my brain is 
working.You should try it sometime, you could start with counting. 
It's 7 ics  (5 for the adc) if you include the analog switch and worth 
every one of them. The M5 will have at least 2 of these maybe 3.

There were low-pass filters before the Moog made his ladder. I
guess we're all thankful he built his 16 transistor monster I'm
sure there were others that were easier to build maybe 
even "easier to make a board layout for". duh!

I guess you don't think about this stuff before you write it huh?

-tg ( wondering why I bother.....)