[sdiy] Buchla 258

[elmacaco]

> This brings up one of my pet peeves.
>
> An oscillator produces a sine wave (from the Latin root, oscillare,
> swung).
>
> If a VC? does not have a sine wave out, it is a function generator
> (VCFG), not an oscillator (VCO).
> Total nit-picking, I admit.

Nice!!  I like that kind of thing.

FOr whatever reason I always prefer the since from a filter self-oscillating
than a VCO, it always sounds filtered from vco's, yet the filter sine is so
nice and open.

I remember reading about a modular manufacturer that actually had a sine
generation circuit and didn;t just derive it from another waveform for this
reason.  I think it might have been the technosaurus selector system
oscillators that did this, but I am not sure.

It probably isn't too practical, but I loved it when I heard about it.







>
>
> On Feb 7, 2006, at 12:04 AM, mark verbos wrote:
>
> > Aaron,
> >
> > be careful. In the modded verison on my site, I replaced the
> > discrete OTA with a 3080, Don didn't do that. The discrete
> > comparator allows him to derive a sawtooth in the waveshaper. There
> > is a discrete comparator circuit very much like this one in "The
> > Art Of ELectronics." He switched to 311's in his later oscillators.
> >
> > Mark
> >
> >
> >
> >
> > Aaron Lanterman wrote:
> >> As an addendum to my last e-mail asking for triangle VCOs - my
> >> comments about Buchla before (the discrete OTA) was in regards to
> >> a 259 I think (or maybe it was the Easel 208, I don't remember now).
> >> Anyway, the 258 is different - looking at Mark Verbos' version, I
> >> see the 3080, and the LF356 forming the integrator - and then
> >> there's three transistors forming - what is that? I'm guessing
> >> it's some sort of discrete comparitor, but I'm not sure why Buchla
> >> would want to use that if he had 311s available...
> >> I need up look up discrete BJT comparitors to figure out what's
> >> going on, I think...
> >> - Aaron
> >> ---------------------------------------------------------------------
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> >> School of Electrical and Comp. Eng.    Fax:    404-894-8363
> >> Georgia Institute of Technology        E-mail:
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