||I need some help with the midiDAC/VCO combo
| br>I managed to finish up building the VCO the other day and last night I hooked it up with the midiDAC.
Things went pretty well, but no cigar yet I'm afraid.
VCO and midiDAC respond to the 1V / oct (I have not done precise calibration yet). However, when I release the key the last played note just keeps on going and does not stop playing.
I also noticed that gate output is 4.47 V instead of 5V. R32 should be 10k. I checked all the components before I powered the midiDAC up the first time.
I'll check that resistor out again.
I have also connected the buss wires for KCV. Pins 1 and 3 (midiDAC) and pin 1 (VCO). VCO normalizing is handwired. The other end of the wire is connected to 1V/Oct NC lug.
I'm new to modular synths so there are a lot of things that I don't quite understand yet so chances are that I have done patching and normalizing wrong.
I patched Pitch to VCO's 1V/Oct and then Tri to my mixer (not the module). br> br>
|catatemycaps wrote: |
|However, when I release the key the last played note just keeps on going and does not stop playing. |
VCOs produce sound continuously. The only way to shut them up is by putting their audio output through a VCA or other volume changing device like a VCF or ring mod.
The classic synth chain is:
Midi controller -> midiDAC -> VCO -> VCF -> VCA -> monitoring system
The VCF and VCA will usually have their own envelope generators (ADSR or VRG) to control their cut off frequency and output level respectively. The Oakley ADSR already has a VCA included in it so you don't necessarily need a separate VCA module for this duty.
It is the envelopes that are controlled by the gate signal and turn on and off the sound when you press a note.
|catatemycaps wrote: |
|I also noticed that gate output is 4.47 V instead of 5V. R32 should be 10k. |
That does seem a little low. It should be closer to 5V but it does depend on the voltmeter you have. 4.47V would be enough to trigger the VRG and ADSR modules.
What's the voltage across D3? This is the +5V power rail and should be 5V give or take 0.25V.
Tony br> br>
| br>Ah! See! I am a total newbie as far as modular/analog synths go.
So far I have only been playing digital keyboards (lately Korg M3).
M3 has filters, envelopes etc that you can fiddle with but I had not really given that much thought about how they all really work. They just do and I just play.
99% of time I just use presets and perhaps play with the KARMA engine and don't bother digging deepr in the settings. The basic sliders with cutoff, delay and so on suffice.
But then I got bitten by the analog bug and after that my M3 has been collecting dust.
I also used to build all kinds of electronics kits and thought that hey building my own modular would be so cool. It's just a kit...a big one....a veeery big one. And now I'm obsessed with this project.
I will get it done eventually. I just wish I had more spare time...
Oh, and I'll check that D3 as soon as get home from work.
Thanks a lot again! br> br>
| br>Gate output is ok.
The only mistake was using my model El Cheapo multimeter. I think it is only capable of guessing values.
I was too lazy to setup my desktop meter last night (should sleep at the wee hours and not calibrate a VCO).
Today I used the desktop meter and it shows gate output is just a tad under 5V so all is well.
When I read the instructions on how to calibrate the VCO I thought wow that sounds complicated. Well, it proved to be even trickier.
I think I have it setup at acceptable level now. Woohoo!
Next up: ADSR br> br>