[sdiy] Temperature stable lin-exp converter with a CA3086 or CA3046

[mark verbos]

sounds like an E-mu modular!

mark

Sowa Roman wrote:

> All this talk about exact compensation got me thinking.
> Does it really matter if overall VCO performance is 50
> or 100ppm/K because of not exact tempco, or other components
> temperature response? Standard crystal oscillators are specified
> to have 50ppm (not talking about those expensive 2ppm here)
> and they are the source for 'boring' DCOs. So are we going
> the right path? Someday one may say "those VCOs we have
> nowadays are so boring, DX7 - this had a drift!"
>
> And now about Tim's idea of coreVCO. I'm thinking about
> same thing for some time now. I want to make it even more
> simple. Just expo converter, integrator, comparator, FET.
> CV with response 0.5V/oct able to cope with multiple inputs
> summed before getting into coreVCO and fitting inside +/-12V
> rails, one output (saw). Cap would be external, so one could
> use it for VeryLowLFO as well as RF VCO ;)
> All squeezed on small PCB size, say, 1x1cm. And dipped in epoxy.
> Premium components of course.
>
> Then why stop here. coreVCFs, and others, similar blocks
> with waveshapers, output buffers, input bipolar attenuators
> and we have LegoLikeSynth :)
>
> someone stop me please...
>
> Roman
>
> __-----Original Message-----
> __From: Tim Ressel [mailto:madhun2001 at yahoo.com]
> __Sent: Monday, May 27, 2002 8:17 PM
> __To: Sowa Roman; SynthDIYmailinglist
> __Subject: RE: [sdiy] Temperature stable lin-exp converter with a CA3086
> __or CA3046
> __
> __
> __To all,
> __
> __All this talk about expo converters got me thinking:
> __It would be nice to have a core VCO design. Just an
> __expo convertor and a sawtoth oscillator. Question is
> __what features would be needed to make it ultra-useful?
> __
> __My personal list:
> __
> __* Cheap as possible
> __* At least 5 expo ins, with at least 3 super-matched
> __* Linear in
> __* Hard and soft sync
> __* Ready for stand-alone use
> __* Scalable for any system (CV and sig levels)
> __
> __I'm sure there are others. I think having a PCB like
> __this would be a great goodness. An add-on board would
> __do the wave-shapers.
> __
> __--TR
> __
> __
>
>
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