[sdiy] Basic core designs of commercial analogs

[Grant Richter]

Merry Christmas Jurgen,

Some more crackpot speculation on my part.

I was thinking about the effect of linear FM on the two different cores.

In the sawtooth core, you have a continuously increasing ramp for the entire
cycle. For a triangle core, you reverse the slope during the cycle.

Now if you consider linear FM of the two cores, with a frequency near the
VCO frequency, would it produce the same waveform?

To rephrase it. Would a sawtooth core with a triangle waveshaper, produce
the same waveform under linear FM as a triangle core alone?

The reason I ask is because of the relative polarities of the waveform
slopes. In the sawtooth case, the FM always modulates a positive slope (in
the core itself), in the triangle case, the waveform modulates both a
positive and negative slope (in the core itself).

Thank you!

> From: "jhaible" <jhaible at debitel.net>
> Date: Sun, 22 Dec 2002 12:54:34 +0100
> To: "Grant Richter" <grichter at asapnet.net>, "Synth-DIY"
> <synth-diy at dropmix.xs4all.nl>
> Subject: Re: [sdiy] Basic core designs of commercial analogs
> 
> Just a few that immediately come to mind:
> 
> Oberheim OB-Xa, OB-8
> SCI Prophet 5 Rev. 3
> Moog Memorymoog
> Roland SH-01
> Synton Syrinx
> 
> I'm sure there are many more.
> 
> JH.
> 
> 
> 
>> Can anyone help me out?
>> 
>> I'm pretty sure that most commercial analog VCOs are based on a sawtooth
>> core.
>> 
>> Does anyone know of any commercial synth VCOs based on a triangle wave
> core?
>> 
>> I believe the Buchla 258 is a triangle based design, are there any others
>> that you know of?
>> 
>> Thank you and Merry Christmas.
>> 
>> 
> 
> 
>