triangle VCO help please

[Grant Richter]

Very nice version.

Q7 and Q8 form a comparator. Q8 has to be the positive input since the
hysteresis is applied there. The collector of Q9 is the output. So the ratio
of R37 and R38 should set the switching points. Make R37 larger to increase
the waveform amplitude by moving the switching points further from ground
(set by R38).

----------
>From: mark verbos <a0284520 at addcom.de>
>To: synth-diy at node12b53.a2000.nl
>Subject: triangle VCO help please
>Date: Sat, Nov 25, 2000, 6:52 PM
>

> Hello,
>
> I have built a triangle VCO based on the Buchla 258 and the Electronotes
>
> Option 2 Triangle VCO. I have a small problem.
> http://www.simple-answer.com/258mod.jpg
>
> The waveforms looks  right at all the locations in the circuit (as the
> buchla design) however insted of being +/- 2 volts at the point
> indicated, mine is just under +/- 200 mVolts.
>
> Where in a triangle oscillator does that gain come from? Is that because
>
> of the 3080? The Electronotes one used a 3080 and the Triangle output is
>
> right off of it so I know that one has a bigger voltage. I have been
> trying all kinds of things with no luck.
>
> can anyone help me? All the waveshaping after that point depends on this
>
> level being higher.
>
>
> --
> mark verbos
>
> "if you want something done right, build it yourself."
>
> verbos at simple-answer.com
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>
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>