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calibration testing - julow - 08-14-2023

hello, I plan to do the cv calibration, I don't know much about electronics, would you have any advice and material to advise me to do the best calibration (without spending a fortune) thank you


RE: calibration testing - mgd - 08-14-2023

Which cv calibration?
The one for the main module as described in the manual?
If yes then just follow the instructions, it is straight forward and when you follow the instructions then basically nothing could go wrong (ignoring the question why you think you should calibrate in the first place).

If you wish to calibrate the 16CV expander then you need a proper voltage meter (don't do it with a cheapo multimeter!).
It then is a somewhat time consuming process (you need to perform 11 measurements for each of the 16 outputs) but pretty straight forward as well.


RE: calibration testing - julow - 08-14-2023

(08-14-2023, 10:43 AM)mgd Wrote: Which cv calibration?
The one for the main module as described in the manual?
If yes then just follow the instructions, it is straight forward and when you follow the instructions then basically nothing could go wrong (ignoring the question why you think you should calibrate in the first place).

If you wish to calibrate the 16CV expander then you need a proper voltage meter (don't do it with a cheapo multimeter!).
It then is a somewhat time consuming process (you need to perform 11 measurements for each of the 16 outputs) but pretty straight forward as well.

i understand but when i saw the making sound video (in french at 59.00) obviously it's better to re-calibrate to use the midi, link here : 
oblinhttps://www.youtube.com/watch?v=AKRB0osvj0o
he recommand the disting'ex or mordax data voltmeter but i would like to know if there are an other cheaper and reliable solution. thks


RE: calibration testing - mgd - 08-14-2023

It's your call.

Not everything you find on the internet in general and on Youtube in particular is good advice.

Seriously:
Do you know the precision and the resolution of the Mordax Voltmeter?

The manual does not say anything about the precision but to calibrate it the manual suggests to use a fairly high precision voltmeter (as in 5 digits).

The resolution of the Mordax is 0.01 Volt. That's about 13 cents. Your call if you consider that "precise".

W/r to the DistingEx:
No idea which of the many modes would be used as a Voltmeter. If it is J-5 Oscilloscope:
Oz says about that "...simple Oscilloscope to visualize things rather than do precise measurements".

You need to decide for yourself how much trust you put into a source that suggests either as valid instruments for calibration.

'nough said,
Michael


RE: calibration testing - julow - 08-15-2023

(08-14-2023, 11:31 PM)mgd Wrote: C'est ton appel.

Tout ce que l'on trouve sur internet en général et sur Youtube en particulier n'est pas forcément de bon conseil.

Sérieusement :
Connaissez-vous la précision et la résolution du Voltmètre Mordax ?

Le manuel ne dit rien sur la précision mais pour le calibrer le manuel suggère d'utiliser un voltmètre de précision assez élevée (comme en 5 chiffres).

La résolution du Mordax est de 0,01 Volt. C'est environ 13 centimes. Votre appel si vous considérez que "précis".

W/r au DistingEx :
aucune idée lequel des nombreux modes serait utilisé comme voltmètre. S'il s'agit d'un oscilloscope J-5 :
Oz dit à ce sujet "... un simple oscilloscope pour visualiser les choses plutôt que de faire des mesures précises".

Vous devez décider vous-même du degré de confiance que vous accordez à une source qui suggère que l'un ou l'autre est un instrument valide pour l'étalonnage.

'pas dit,
Michael

thanks Michael for your answer 

Ok i understand for mordax and disting, do you know a better solution for making a good calibration ? 
Voltmeter, multimèter or other solution ? Modèle ?


RE: calibration testing - mgd - 08-15-2023

(08-15-2023, 11:23 AM)julow Wrote: Ok i understand for mordax and disting, do you know a better solution for making a good calibration ? 
Voltmeter, multimèter or other solution ? Modèle ?

I'd get me a good Multimeter. You could go for a Voltmeter but unless you try to be extremely precise, a good multimeter should do.

Next question to answer is required precision.
That depends on what you wish to use it for, aka what is it that you wish to measure. The NerdSEQ uses 12bit DACs for a range of 10V, i.e. about 2.5mV is the difference between adjacent voltages. For that a precision of 1mV in the range of 0-5V seems good enough. That is about 4 digits or something like 10000-20000 counts (the later being the measure of precision given on many online websites).
If you wish to calibrate 16bit DACs found in some quantizers you probably should have a multimeter with at least 5 digits precision, i.e. 100000 counts or better.
There's a limit to what makes sense in the context of modular analog synths though (your patch cables will have a resistance of 0.1-0.2 Ohm and the impedance of inputs is in the range of 10-100kOhm which results in the loss of 0.001-0.01mV per Volt via your cable - small enough that you can ignore it but big enough that calibrating to e.g. 8 digits precision would be pointless).

Models:
There are lots of decent vendors. Fluke, Brymen and quite a few others.
I own a Brymen BM869s (about 180/190€ a few years ago) which IMO is at the upper end of the scale that makes sense in the context of modular synths.
Basically everything with enough precision (see above) for your intended purpose should be fine.
If you happen to own a decent oscilloscope that should be fine as well. You then would not need a seperate multimeter though having both is convenient as well.

I still don't understand why you think you should calibrate in the first place though.

HTH,
Michael


RE: calibration testing - yrn1 - 08-15-2023

Also note that precision multimeters need to be calibrated too. Most of the time, new ones come factory-calibrated, but I had a 100€ Fluke a couple of years ago that was 5mV off. Recalibrating it would cost another 20-30€. I agree with Michael: there is usually no need to calibrate a nerdseq. Any analogue oscillator would be waaayy more off than the nerdseq.