The 3340 VCO category is for all things 3340, from our EU and discontinued MU modules, to the submodules, and the IC itself!
I built one of the Electro-Smith VCO modules and am trying to calibrate it. I set the frequency to C2 and then pressed the C3 key on my keyboard and ended up getting C#3. I turned the trim pot to lower the frequency to C3 and then pressed the C2 key and got B2. I adjusted that and went back to C3 and again got C#3. I did this many times and just go back and forth between these two values without converging. How many iterations should I expect to do?
10+++ iterations, if you truly meant what you said and only tried it 2-3 times then you need to do it a lot more.
One tip is that you don’t need to have it tuned perfectly to a C to know it is in tune.
Just need to see that the frequency doubles for each volt.
I use the built in tuner in Ableton Live on Hz mode and just make sure that 1 volt is 2x the frequency of 0 volts. Then I do the same for 2 volts and make sure the frequency is 4x 0 volts.
Then I tune the oscillator to C
Wondering if you ever figured this out as I’m having the exact same problem…0V tuned to C, 1V gives me C3 so I trim to C, then back down to 0V and I’m at B. I got pretty frustrated so I left my system on and walked away for 2 hours to make sure it was properly warmed up. I then proceeded to do this exercise back and forth for 30 minutes and it never got any better. Hoping someone has the magic solution to this because otherwise the oscillator functions perfectly and sounds great! I also built the Electrosmith filter and got it tracking a few octaves without issue which makes this even more perplexing.
I haven’t tried it yet but one of the descriptions I found for calibrating the VCO used the trim pot to adjust the high end but the normal module frequency controls to adjust the low end. Maybe with that technique the values will converge.
Are you referring to the HF trim pot? I believe that is for the higher frequency tracking if I understand the calibration procedure in the manual correctly. I never even got that far as I couldn’t even get C1 to C2 to track using the V/Oct trim pot.
No, I’m talking about the frequency adjust knobs on the front of the module. As I mentioned, I haven’t tried this yet.
Ok - Please let us know your results once you try.
There are two different types of tuning for an analog oscillator.
Using the knobs on the front you can tune the overall pitch.
Using the trim pot on the back you can tune the pitch scaling. By pitch scaling I mean the octave per volt scaling. The trim pot is used to make sure the frequency doubles (same thing as increases by one octave) for each volt.
If the octaves are out of tune from each other then you MUST tune it using the trim pot on the back. The manual explains how to do this. Make sure you use the trim pot that says “v/oct”
You can most likely ignore the HF trim pot, this is only used to tune REALLY REALLY high pitched notes and I’d say 95% of people will never need it.
What I do is send the oscillator a slow sequence of 0 volt and 3volt over and over, you then turn the **slowly ** turn the trim pot on the back until 0v and 3v are the same pitch. You can use your ear or a tuner to do this. A high quality strobe tuner will make it easier, but it is possible with your ear alone if you are a musician.
I’ve got two of the VCO submodules tuned perfectly over 7 octaves, but it did take a little patience and I’ve been a musician my whole life which might help
Just wanted to say thanks and report back that this method worked. I’m tracking over 4-5 octaves easy. Only took about 10 minutes to dial it in. However, I do think the calibration procedure in the build guide is not very clear…I always read that you used the trim pot on the back of the PCB for all of the calibration - not switching between the trim pot and the fine tune knob.
I’m glad to hear it worked for you. I haven’t tried it yet myself although I recently purchased 12 of the ElectroSmith VCO submodules so I’ll have a lot of calibrating to do soon!