Voltage controlled oscillator with three waveforms, modulations and low frequency mode.
Documentation: modules — oscillator
Product page: microrack — oscillator
2 Likes
Hi. I would like to ask what is voltage range for the Pitch input? Is it bipolar or unipolar?
And what voltage corresponds to A4 440hz wave?
All CV voltage is in range from -5 to +5 volts, 1 V/oct.
Base oscillator frequency is tuned by pitch knob.
2 Likes
Any chance we might be able to get a sync/reset input? Would come in handy in lfo mode and who doesn’t love some hardsync.
Yes, we plan to add sync input in release version. Adding the hardsync will be simple, but I will think about softsync input also.
2 Likes
Would be there anything for a sine wave, btw?
Maybe we should have made a stretch goal out of it 
Hello!
We have a great update on the VCO schematic. I found a current leakage of about 20 µA through the Schottky diode, which caused the 1V/oct law to go out of tune, even at the second octave. After changing the diode to a BAV99, we now have 6-7 octaves perfectly tuned!
Also, the LFO range has become wider, and the oscillator can produce an ultra-long period of up to 1 minute!
Now I’m working on the triangle converter, hard sync input, and output levels.
5 Likes
After a lot of work, we’ve finished debugging the VCO module!
So, triangle output is implemented, hardsync works, output levels is 0…5 or -5…+5 with 5% accuracy!
7 Likes
I don’t want to spam the jams thread with technical tests, so I’ll post this here, as it is about the oscillator: a playful way of testing the limits of oscillator stability, and… yup, there they are! 
Two oscillators, very slightly detuned (by a fraction of a Hertz), to get this flanger-like comb filter effect.
The oscilloscope shows one oscillator at the bottom (yellow) and the mix of the two at the top (blue).
The LFO (bottom right) triggers the envelope (bottom left) which controls filter cutoff. No VCA, as I didn’t want confusion on the scope screen.
The oscillators are obviously pretty stable, but they seem to have slightly different ideas about intervals (the phase difference changes much faster at higher pitch).
At the end of the video I blew it I blew on it a few times (you can see the wires shiver) to change the temperature, and the beat frequency immediately changed. This is one setup where a good sneeze could destroy everything! (well, at least it would require ten minutes for temperature stabilisation and half a minute or so of tuning)
Edit: I made another video at a higher pitch, where the beat frequency drifts off rather faster.
2 Likes
I watched both videos and everything seems normal behavior for voltage-controlled oscs. You could try syncing them but then you would probably lose the detune, but worth trying either way
2 Likes
You’re right, oscillator is not perfectly stable: at first, you need to wait about ~2 min after power up before frequency become stable
and also it changes with temperature.
In next version I prefer to add thermistor to compensate temperature drift, we already received a prototype and I’ll check new version soon
1 Like