Tunning of "free running" (0.000v) ocillators

[daveholiday]

Hey all, I thought this might be a more general modular question, but perhaps more suited here as there aren't quite as many various VCO modules in 5u.

My favorite Mr. Garrison quote from South Park..."There are no stupid questions, only stupid people"

Most, not all, of my oscillators "free run", no input, all tuning knobs at default 12 o'clock at "C" I assumed this was a "standard" as all three of my MIDI to CV controllers default at 0v,1v,2v,3v...etc on the "C" key

The reason why I ask is a have a couple oscillators that, with no input and default settings, are in "E".

It was a problem during calibration because I was expecting C at 0v and 1v.....

Is the 0v and 1v/oct based on C? I understand that this is all correctable with the fine tune knob, but I did want to get some clarification if there was a "standard" that most people follow.

[Flareless]

I don't know if there is a fixed Standard but I tune all my oscillators to C when I zero my modular.

For oscillators without quick Range Switching I will often tune to C in different octaves. Just to switch things up a bit.

[daveholiday]

Perhaps I should bust out the Minimoog.....as that would be the 5u standard right? Alas, it has only been out of the box once......a crime I know....

[Ockeghem]

The minimoog has a handy A440 tuning reference...
But, at the risk of seeming stupid, which oscillator or oscillators in 5U/MU are giving you the “E?”
Do they have red panels?

[KSS]

Is the 0v and 1v/oct based on C?

No. But see the next part of the reply.

but I did want to get some clarification if there was a "standard" that most people follow.

It likely has to do with the early KBD circuits where 0V was one end of the resistor chain. Since integer ocatave keybeds start with C, 0v = C was the easiest path. And since manufactured synths outsold DIY, it became a 'standard' as time went on.

Then you've got the minimoog entering with a 44note keybed. 0v is still the bottom of the resistor chain, but the bottom key isn't C anymore.

[daveholiday]

Is the 0v and 1v/oct based on C?

No. But see the next part of the reply.

but I did want to get some clarification if there was a "standard" that most people follow.

It likely has to do with the early KBD circuits where 0V was one end of the resistor chain. Since integer ocatave keybeds start with C, 0v = C was the easiest path. And since manufactured synths outsold DIY, it became a 'standard' as time went on.

Then you've got the minimoog entering with a 44note keybed. 0v is still the bottom of the resistor chain, but the bottom key isn't C anymore.

So to put it very loosely 0v=C is the "standard" that most gear CV gear is following these days?

[daveholiday]

The minimoog has a handy A440 tuning reference...
But, at the risk of seeming stupid, which oscillator or oscillators in 5U/MU are giving you the “E?”
Do they have red panels?

PM sent

[daveholiday]

The minimoog has a handy A440 tuning reference...
But, at the risk of seeming stupid, which oscillator or oscillators in 5U/MU are giving you the “E?”
Do they have red panels?

Who the Hell has Red panels in 5U? they should be dragged into the street and shot!!!!! Black and white is just fine for the old pony-tail wearing fuddy-duddys of the MU world....that is the TV we grew up with.

Gotta run.....there are some damn kids on my lawn that I have to go yell at!

[josaka]

I tune mine to C as well .. but isnt the standard A... ?

[Thalassa]

Normally VCOs with rotary octave switches like the q106 and with no cv applied and fine tune in neutral position , they are tuned to C. In VCOs without octave ranges like my C104 or the ones in the odyssey or the ARP 2600 they are calibrated to a base frequency when the frequency knob is at minimum. In the c104 and the arp odyssey they are tuned to 20hz in the arp 2600 to 10 hz.

In general when you calibrate the VCOs the first thing you do is the 1v/oct calibration. After that you define a base frequency without cv applied. In a VCO with rotary switches, normally you set the switch to the lower setting , (for example 32) and you tune the VCO to a base note , that is normally C, but you can set your VCO to any base note you want.

[KSS]

re: Thalassa just above
Contrary to this advice, I would suggest you *not* use the lowest note range of the switch. Better to use something in the low mid-range. Many times that lowest range isn't even labeled in 'footage' -and is labeled L.F. or similarly non-specific- because it's not expected to be as perfectly in tune as the higher ranges.

Fitting the ideal exponential curve to the analog reality often or usually means choosing which two points on that expo you'll use for calibration to get the best results for your use. For different VCOs the choice can be different. We fit the curve with two points and *then* check our results with the additional points arrived at by rotating the range switch. Sometimes you can get better results by using a different two points than the mfr. calibration calls out.

Ultimately it's this curve-fitting that matters more than what 0volts means. At least in the fully analog realm.

[KSS]

I tune mine to C as well .. but isnt the standard A... ?

Different ways of looking at the same thing. A 261.nn "C" equates to a 440.0 Hz "A".

If you think about it, the choice of 1st violin -concertmaster's "A" for concert pitch is a little like the reply I just posted. Because an orchestra or string quintet chamber group is nothing if not analog!

By choosing to let the 1st Violinist 'set' the pitch, the overall 'voice' is also somewhat defined. Using a different instrument as the 'setting' point would introduce a different 'match' to the expected results.

[hamildad]

Chris at Learning modular did a good post about VCOs that all have a different pitch at 0V.

I think My Moon 501s are neither C nor A, as I use a 440Hz reference (Q123) and have to tweak up a little to hit it.

[Faustgeist]

[/quote]
Who the Hell has Red panels in 5U? they should be dragged into the street and shot!!!!! Black and white is just fine for the old pony-tail wearing fuddy-duddys of the MU world....that is the TV we grew up with.
[/quote]

The only red panels I've seen in MU are tube based Metasonics/Zerosum. And those panels might have been custom anyway.

[Ockeghem]

Actually it’s the infamous Buchla LSD-laced red panel I must have been thinking of...

[josaka]

one bad thing about 440 is ... its only 440!.. no octaves.. + -