I just realized the link I posted got shortened so it ends in "anal ... oller.html". that's funny to me. Moving right along...
low-gain wrote:You press a key on your CV keyboard.. 2 signals come out of the outputs.
1. You press down on the key, it sends a Gate on (+voltage), which tells the oscillator to turn on. at the same time the note voltage is sent out to tell tell the oscillator what frequency to play.
2. you let go of the key. the Gate signal stops and the note shuts off..
I can't recommend ray wilson's projects enough! they're great. try the sound lab mini synth!
from there build his sequencer that you can run w/ the sound lab mini synth for more fun!
fantastic! thank you. the only thing keeping me from going forward with one of those is the price.
tacticalbread wrote:
what class do you build synthesizers in? I've taken classes on Synthesis, and analogue synths, but we never built anything. Sounds like an awesome class.
's actually a physical computing class. we're just doing some basic circuit stuff. I learned to solder and balance an LED with resistors! go me!
nitro2k01 wrote:theDutchess wrote:-is this interchangeable with all oscillators, (read: is the relationship between voltage output and frequency related mathematically?)
Low-gain answered most of your questions, but I'll address this one.
1 V/oct is a widely recognized and used standard in modular synthesis because it makes things easier if oscillators (and filters, not to be forgotten) follow a common standard. There are others, less common ones as well, such as Buchla's 1.2 V/oct, which elegantly translates into 200 mV/semitone. (Don Buchla is a famous pioneer in modular synthesis who started his career in 60's. Another name to look out for is Serge)
However, 1 V/oct (1 V/some arbitrary interval) is not a magic intrinsic property of oscillators. The oscillator needs to be designed and tuned for that standard in order to obey it. Often, a high precision oscillator has two trim potentiometers for tuning, of which one is for fine tuning in the higher octaves. This is needed because the oscillator is likely to deviate from its voltage/frequency curve at higher frequencies. Another problem is temperature instability - the oscillator detunes itself once it warms up. This problem is solved by thermocoupling a heat sensitive resistor to the critical transistor, to compensate for these effects. Thermocoupling means that the components are placed in such a way that they keep the same temperature, in the case of this resistor, by joinng it to the transistor with a blob of thermal grease.
Now I'm not expecting you to understand all of that immediately (hopefully you will one day 
) But rather I'm trying to explain that getting a high precision or even low precision a 1V/oct response is not a trivial thing but requires it to be a part of the design. Specifically, making an APC do 1V/oct would likely require some sort of voltage scoling.
I get how the 1v/O works. I love synthesizers and I was really excited to see NIN with a modular a couple tours ago. Buchla, to me, has a much more "electrical" sound than other electronic synthesizers. So, if I understand this, the oscillator has to be callibrated so that:
whatever the voltage per octave the controller was designed for, the oscillator will correspond to it
the tuning on the keyboard matches the tuning of the oscillator
in mathy terms, changing the frequency and phase of a parabola if that makes sense?
I don't even know how the first poly keyboards were wired.
