[sdiy] Dual oscillator cores?

[Ian Fritz]

At 06:36 AM 10/19/2009, Jerry Gray-Eskue wrote:

><<I'm not sure how triangle cores
>switch the direction,>>
>
>Take a look at this, it is near to a classic Integrator / Comparator setup
>and may help clear up how triangle cores operate.
>
>http://www.musicfromouterspace.com/analogsynth/NewAugustRampLFO.html

A typical Tri VCO is current-controlled and uses transistor switches to 
reverse the input current direction.  My version uses analog switch ICs to 
do this (as well as to reverse the threshold voltage) and is quite fast. 
Compensation of the IC's capacitance according to the manufacturer's 
suggestion really helped with the speed. It switches in about 300 us, 
actually quite comparable to my best Saw cores.

Ian
http://home.comcast.net/~ijfritz/sy_cir4.htm
http://www.electro-music.com/forum/topic-28713.html&postorder=asc