Something new(ish)? (Re: 1970's again? (was Re: [sdiy] pro EQs))

[Scott Bernardi]

This might be the Electronotes circuits you were talking about - Bernie 
called it a "Timbre Modulator".
http://home.comcast.net/~sbernardi/elec/og2/og2_timbremod.html


Bill Felton wrote:

> There's also a very nice ElectroNotes circuit that, IIRC, had 
> back-to-back diodes in the feedback path of an op-amp, (output being 
> then basically center-clipped), then amplifying and adding the normal 
> (or inverted) center-clipped signal back in to the original.  At full 
> effect on triangle wave input, this gave frequency tripling.  But the 
> intermediate stages from tri (or other continuously varying, ie, no 
> pulse wave inputs allowed) to the 'full effect' setting gave a sound 
> transform that was rather the inverse of typical synth filtering -- 
> you went from a low-harmonic to high(er)-harmonic content sound, under 
> vc of center-clipping amount and mix.  Since this needed no exp. 
> converters to track, it was significantly cheaper than a filter 
> circuit, gave an effect similar to, but different from, the 
> time-variation in timbre from a filter, and thus played a comparable 
> role in the patching ecology.
> (I've got two I built and love them; Cynthia is panelling them for me, 
> along with my EN MultiPhase Waveform animator.  )
> cheers,
> Bill
>
> On Dec 31, 2004, at 8:35 AM, John Loffink wrote:
>
>> Look here:
>>
>> http://www.oldcrows.net/~patchell/synthmodules/shaper.html
>>
>> and here:
>>
>> http://www.wavemakers-synth.com/motm/dws.html
>>
>> for examples of diode waveform shapers.
>>
>> I find my shaper useful for adding gradual degrees of distortion to
>> waveforms, or making "composite" tones by modulating with waves from
>> multiple VCOs or VCFs.
>>
>> You are correct that these circuits originated with analog computing, 
>> yet I
>> have never seen an implementation in "classic" (i.e., Moog, Buchla, 
>> Serge,
>> Emu, etc.) modular synthesizer format.
>>
>> John Loffink
>> The Microtonal Synthesis Web Site
>> http://www.microtonal-synthesis.com
>> The Wavemakers Synthesizer Web Site
>> http://www.wavemakers-synth.com
>>
>>
>>> -----Original Message-----
>>> From: owner-synth-diy at dropmix.xs4all.nl [mailto:owner-synth-
>>> diy at dropmix.xs4all.nl] On Behalf Of Anthony Ankrom
>>> Sent: Friday, December 31, 2004 8:09 AM
>>> To: Paul Maddox; Synth-Diy
>>> Subject: Something new(ish)? (Re: 1970's again? (was Re: [sdiy] pro 
>>> EQs))
>>>
>>> I have read about something that I don't think anyone's ever applied to
>>> synth work, but it might be
>>> interesting.
>>>
>>> Just the other day I stumbled across an old article about "non-linear
>>> transfer functions". The circuits in the article
>>> used very large arrays of "forward biased" diodes in the feedback 
>>> loops of
>>> op-amps. It said forward biased but
>>> the diodes were "pointing" the same way as the op-amps so I would think
>>> this
>>> would be reversed biased, but hmm
>>> maybe it was because it was in the inverting input?
>>>
>>> And the arrays seemed to be strings of diodes of varying/increasing 
>>> length
>>> in parallel. Like the first was one in
>>> parallel with a string of two in parallel with a string of three and 
>>> so on
>>> -
>>> with variations on this theme.
>>>
>>> The aim here was some analog computing application, but isn't that what
>>> analog synths are in a nutshell?
>>> They're analog number crunchers with audio user interfaces.
>>>
>>>
>>
>>
>>
>>
>
>