Triangle VCO help please

[Magnus Danielson]

From: mark verbos <a0284520 at addcom.de>
Subject: Triangle VCO help please
Date: Sun, 26 Nov 2000 01:17:59 +0100

> Hello,

Hi,

> 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

Ah, haven't seen that before...

> 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.

Try to fool around with the R29/R30 divider. It forms the feedback
path through Q7, Q8 and Q9.

Cheers,
Magnus