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Q106 Calibration/tuning
MUFF WIGGLER Forum Index -> 5U Format Modules  
Author Q106 Calibration/tuning
LoveHertz
Does anyone know an alternate way of calibrating the Q106 without access to expensive test equipement? I mean apart from the technique in the data sheets that requires a $3000,00 frequency counter?
nerdware
Chromatic tuner and/or your ears. thumbs up That's the cheapest hardware method I know. Really very cheap! Effective, too. There are free software apps that will do an equally decent job.

A scope can also be used. (Ray Wilson has a 2-part video tutorial on his YouTube channel.) Some multimeters have a frequency measurement function. As with tuners, you can find free frequency counter apps. (About a month ago I wrote a simple one using Csound and the ptrack opcode, just to see how well it worked. It worked very well!)

Has anyone tried using tuning forks to calibrate their VCOs? lol
Xero
aren't there various multimeters that have frequency counters? like an old fluke 8060a? they're not that expensive, maybe 50-60 bucks on ebay, assuming its all working and calibrated. I did get one on ebay that was horribly off, but I think it was an exception not the rule.

I have a newer fluke 289 now and it's fine, but it's also more $$$, I also got it used on ebay though for like half price.
Just me
I use a strobe tuner and a dvm. As accurate as anything.
The Hamburglar
I use Guitar Toolkit on my iPhone.
KnobHell
LoveHertz wrote:
Does anyone know an alternate way of calibrating the Q106 without access to expensive test equipement? I mean apart from the technique in the data sheets that requires a $3000,00 frequency counter?


Please... You don't need 3 k in test equipment to calibrate an oscillator....

Both my 4 1/2 digit DMV and frequency conter were less than 1/4 that combined.

Also... My DIY motm 300s tracked better than my q106's.

Iow.. You are never going to make it perfect with a million dollars in test equipment.
LoveHertz
Ok thanks for the advice on the gear everyone...its good to know some easy to get equipment is all thats needed...

but some alternate proceedures and techniques apart from the dotcom data instructions page would be good to hear and how reliable they are..that is if others think they have another way thats just as good. thanks
Tronman
How can you tell if your Q106 is in need of calibration? I have a few that I need to set the Frequency knob about half way between 0 and +1 for them to be in tune. Is this considered within acceptable tolerances?
nerdware
Tuning and scaling are very different things. It's like the difference between addition and multiplication. Some VCOs have a trimpot for the tuning offset. You can adjust that to get your prefered frequency when the freq knob is midway. However, I can't tell if the Q106 has such a trimpot. It has something labelled "100K BASE" in the manual, so that might be it.
Savage
Tronman wrote:
How can you tell if your Q106 is in need of calibration? I have a few that I need to set the Frequency knob about half way between 0 and +1 for them to be in tune. Is this considered within acceptable tolerances?


I'd like to know how to tell that Q106's need calibrating, as well. I have a few years on some of mine, and I, too, have to turn the Frequency knob to between 0 and +1 on some of them to get them in tune. They all seem to track just fine across at least five octaves. I'm guessing that if they cease to track properly that they need calibrating?
megaohm
Savage wrote:
Tronman wrote:
How can you tell if your Q106 is in need of calibration? I have a few that I need to set the Frequency knob about half way between 0 and +1 for them to be in tune. Is this considered within acceptable tolerances?


I'd like to know how to tell that Q106's need calibrating, as well. I have a few years on some of mine, and I, too, have to turn the Frequency knob to between 0 and +1 on some of them to get them in tune. They all seem to track just fine across at least five octaves. I'm guessing that if they cease to track properly that they need calibrating?


Set all your Q106 range switches and fine pots to the same setting and adjust the "base" trimmers until they match.

For adjusting the scale/ 1V/OCT response you can go ultra simple and use a synth/instrument/whatever and tune you VCO to that with your ears. I often use a simple VST plugin sine synth for this.
Putte
Two of my oldest Q016CRS seems to be out of scale, and I did a lame attempt to calibrate them yesterday. They outcome says I need help. I Think I tuned them quite well, but I never got to the scaling as Iwanted.

Thing is I got a simple tuner and an oscilloscope, with a freq. counter. I realize a voltage calibrator would do the trick, but how do I manage without one? I use a 37 note keyboard, with a boult in Kenton Pro solo (So, it sends CV/gate to the modular).

I´ve used the .com instructions, and got to point 5. What does it mean to center the pots, setting them parallell to the board (straight up and down)?

Then comes the core of the process. I´d like to know what the three pots involved do. Is it like this?:
-Base freq. sets the very bottom of the whole range, stretches it down all the way down to the cellar (basement).
-V/Octave seems easier. It has to be the pot adjusting hertz per volt, stretching out the octaves correctly.
-High freq. must be to opposite to base freq., setting the very highest possible note.

Finally, "check for 32, 64, 128," and so forth. It may be a ridiculous question, but what are those numbers? Does it simply mean I shloud check every octave for accuracy?
burdij
There was a thread a while back about a tuning program that uses the MIDI/CV and an input audio channel on your computer to test and graph the tuning of a VCO. The thread is here: VCO Tuning

This might provide a "no test equipment" method of tuning for you. I was able to use this program even with one of those cheap $3 class compliant USB audio modules from eBay. You do need a fairly accurate MIDI/CV converter. I also found that avoiding clipping in the audio input is important.

EDIT- I just checked the Github link for the binaries which appears to still work. Also, there are now versions for Windows, OSX and linux.
burdij
Putte wrote:


Then comes the core of the process. I´d like to know what the three pots involved do. Is it like this?:
-Base freq. sets the very bottom of the whole range, stretches it down all the way down to the cellar (basement).
-V/Octave seems easier. It has to be the pot adjusting hertz per volt, stretching out the octaves correctly.
-High freq. must be to opposite to base freq., setting the very highest possible note.

Finally, "check for 32, 64, 128," and so forth. It may be a ridiculous question, but what are those numbers? Does it simply mean I shloud check every octave for accuracy?


The Base pot sets the position of the scale within the voltage range. I believe the base is adjusted with the octave switch at 8' and the fine control knob at the center of its range. This corresponds roughly to middle C (263Hz) with a zero volt input to the 1V/Oct input and zero volts on the FM inputs.

The V/Oct is then adjusted for the span by inputting +1V, +2V, etc. This should be done first with lower octaves as the setting will need to be tweeked slightly when the High Freq or HF Comp setting is adjusted. This setting accounts for the bulk resistance of the transistors in the exponential converter. The effect of this is that as the frequency goes up (more current) the output current does not go quite high enough to get to the next octave. This pot adds a small amount of compensation depending on the input voltage to give the current output a little kick in the pants.

This is usually adjusted by going between a pair of low voltage octave intervals and a pair of high voltage ones and slowly increasing the HF Comp setting on the high pair until they track the octave changes. This is a difficult adjustment and takes time but is simplified by the tuning program to a considerable extent.
Flareless
burdij wrote:
There was a thread a while back about a tuning program that uses the MIDI/CV and an input audio channel on your computer to test and graph the tuning of a VCO. The thread is here: VCO Tuning ...


VCO Tuner is an outstanding utility!
Putte
Thanks for helping out. I´m more than lost when it comes to electricity, and should probably play the fluit instead…. or claves!
There might be something close to a voltage calibrator in the physics department at work (college). I sneaked in and messed with one of these, a power supply that seemed to generate between 0 and 30 volt:

https://www.alega.se/images/2.31122/spanningsaggregat-ac-dc-0-30-v.jpe g
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