Fwd: [sdiy] RE: WP20 VCA

[ethan tripp]

sorry, i did it again. i'm not used to this yet.

> can anyone recommend any other mini synth projects that are fairly 
> simple for beginners and are finished as far as development is 
> concerned.
> and please don't say fatman, i'm well aware of the paia stuff and am 
> trying to ignore it.
>
> thanks,
> -et-
>
> On Friday, September 12, 2003, at 12:42 PM, Scott Gravenhorst wrote:
>
>> Is this a contest or a dare or what?  (c:
>>
>> Grant Richter <grichter at asapnet.net> wrote:
>>> Hi Ray,
>>>
>>>> I just went and did some breadboarding to see what I was thinking 
>>>> 20 years
>>>> ago. The answer... not much. At best the circuit is very 
>>>> non-linear. In
>>>> other words if you start with a triangle wave in you get a severely
>>>> distorted triangle wave out. While experimenting I had to double 
>>>> the gain
>>>> (200K instead of 100K feedback resistor) so that the signal was a 
>>>> little
>>>> more above the noise level of the chip. I recommend that you find 
>>>> another
>>>> VCA circuit. I have a couple of pretty low parts count VCAs on my 
>>>> site but
>>>> the WP20 stuff was the misguided effort of a much younger and not 
>>>> very
>>>> electronically savvy man (me). I can't even remember if I had an
>>>> oscilloscope back then.
>>>
>>> Somebody used the term "anti-synth" a while back. That go me 
>>> thinking about
>>> a synth deliberately designed from nasty, distorted, non-conforming 
>>> and
>>> imperfect modules. (kind of like a PAIA Gnome, only deliberately 
>>> this time,
>>> just razzing you John!!!)
>>>
>>> So let's call this circuit, part of the "anti-synth" collection. 
>>> <grin> I
>>> found a VC waveshaper that sounds like a train wreck (not 
>>> literally), I will
>>> post an "anti-synth" design at some point.
>>>
>>> Like that CA3096 based VCO with 10K of DeFranco compensation. While 
>>> still a
>>> VCO, it has the most waveform shift with frequency. Bad in the 
>>> traditional
>>> sense, but a design win for an "anti-synth".
>>>
>>> No offense intended here. The brilliant people on this list who are
>>> dedicated to producing ever improved designs, have my complete 
>>> admiration.
>>> But it is kind of fun to reverse your perspective, and see how BAD 
>>> you can
>>> design, while still making a module function.
>>>
>>
>> =========================================================
>> - Where merit is not rewarded, excellence fades.
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>>
>> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>> -- Linux Rex         | RedWebMail by RedStarWare
>> -- FatMan: home1.gte.net/res0658s/FatMan/
>> -- NonFatMan: home1.gte.net/res0658s/electronics/
>>
>>
>>
>