A few questions from a newbie synth builder

[volting]

Im new to syth building. Ive messed around with some basic 555 based designs, but now Im looking to something a little more sophisticated.

Iv bought a bunch of XR2206's which I plan to use for VCO's and LFO's
I will use an MCU(probably an Atmega16L) and DAC for control voltages, ADSR's and sequencing.

The block diagram below is the basic idea for the synth, -is this ok? any suggestions ?

My problem is I have no knowledge of VCF and VCA design I'm also unsure how to configure the XR2206 to be voltage controlled.

I have studied all of the basic opamp circuits including integrators, differentiators. Iv also studied the wein bridge , phase shift, and squarewave oscillators, comparators, clipping circuits, dc restoration, peak detectors, active rectifiers, opamp based Pulsewidth modulation circuits, ICL8038, ramp generator , LM566 & LM331.

So I dont think I should have *too* much of a problem learning VCF & VCA design if I could find some online tutorial or similar.

So is there any where that is good place to start to learn about basic VCF & VCA design ?

Also I'm hoping to be able to build these out of basic components I have at hand i.e. discrete components + op-amps.(to begin with atleast, if thats possible)

[volting]

I had a closer look at the datasheet for the XR2206 and out how to control voltage it.

I also found some OTA's in my chip inventory.
2x CA3080's and 2x LM13700

Looking for some simple circuits to start with for VCF, VCA and maybe ADSR Are any of the VCA / VCF circuits in the LM13700 worth bothering with?

[Sound]

Hello Volting,

Seems that the book "An Analog Synthesizer for the 21st Century" by Thomas Henry, will fit your needs.
It is a collection of schematics for a complete synthesizer, that uses chips that you are mentioning (xr2206 VCO, LM13700 VCO...)

Also interesting is the book "Making Music With The 3080 OTA" That explains and show diferent circuits with the OTA CA3080, same circuits could be applied to the LM13700. I think.

http://stores.lulu.com/magsmoke

The VCO chip cookbook also by TH explains how make a VCO with the xr2206 as well the 566, the 8038 and VCO test gear like forexample a Tenstep voltage reference.

I think that State Machine has it available.
http://electro-music.com/forum/topic-18659.html&start

[volting]

Thanks those books look great, is there much explanation of how the circuits work though as thats what I'm interested in rather than just blindly copying circuits component for component.. anyway I'm a little short of cash at the moment so there not an option for me right now.

[Sound]

Hi Volting, look at Scott Stites site:
http://www.birthofasynth.com/index.html
There are explained some circuits by TH like a VCA and VCO with OTA, the XR2206 oscillator and also the very interesting circuits by Scott Stites like the Klee sequencer.
Hope it helps.

[volting]

Thanks, just had a quick look, looks descent, I'm working on a few other projects at the moment, when I'm finished Ill have a proper look.