A4 CV out is waaaay off

Hexeract · 2014-07-30T13:38:18.000Z

I have experience with manually calibrating analog synths, and tuning oscillators, and scaling them. All my synths are 1 volt per octave. I understand CV pretty well. The A4 is putting out CV that is out of scale, and out of tune. I looked through all the sub menus and there’s no way to recalibrate this.

To be sure, I check my synths pitch (moog sub phatty, moog sub 37, and future retro XS,) with Midi in from various controllers, they all checked out. Then I ran CV out from my other CV sequencer, not as dead on as the Midi, but still within +/-5 cents from C2 to C6. Acceptable. Then I ran the A4 CV output. It’s like -13 cents on C2, then jumps all the way down to -20 cents Bb when I play C3. C4 is like -33 Bb. Clearly the scale is wrong, and so is the tuning.

There has to be a way to manually calibrate this right? I ran the automatic oscillator calibration, but it didn’t help. I looked in all the CV sub menus and at all the options, didn’t see what I needed.

Is there something I’m missing?

analogback · 2014-07-30T13:47:03.000Z

trimpots, get in there!

Mihajlo · 2014-07-30T13:55:32.000Z

I had no problem using slim phatty with cv (after it warms up), but had some wierd pot problems with Minitaur.
but that was after i installed minitaurs newest OS… back to Rev 2, and it was fine…

my A4 is going to this user: analogback (i know you are worried man, i feel you), but i think the newest the synth/module, the less problem youll have…

dcsux · 2014-07-30T14:03:32.000Z

""Hexeract"":

I have experience with manually calibrating analog synths, and tuning oscillators, and scaling them. All my synths are 1 volt per octave. I understand CV pretty well. The A4 is putting out CV that is out of scale, and out of tune. I looked through all the sub menus and there’s no way to recalibrate this.

To be sure, I check my synths pitch (moog sub phatty, moog sub 37, and future retro XS,) with Midi in from various controllers, they all checked out. Then I ran CV out from my other CV sequencer, not as dead on as the Midi, but still within +/-5 cents from C2 to C6. Acceptable. Then I ran the A4 CV output. It’s like -13 cents on C2, then jumps all the way down to -20 cents Bb when I play C3. C4 is like -33 Bb. Clearly the scale is wrong, and so is the tuning.

There has to be a way to manually calibrate this right? I ran the automatic oscillator calibration, but it didn’t help. I looked in all the CV sub menus and at all the options, didn’t see what I needed.

Is there something I’m missing?

Still sounds like you need to play with the V/Oct value on your A4 (ie. Function + CV A/B/C/D)

cv_page.jpg880×313 37.2 KB

analogback · 2014-07-30T14:16:13.000Z

hmm… so you can adjust the C voltage and voltage scale from this menu?
)

analogback · 2014-07-30T14:18:03.000Z

""Mihajlo"":

I had no problem using slim phatty with cv (after it warms up), but had some wierd pot problems with Minitaur.
but that was after i installed minitaurs newest OS… back to Rev 2, and it was fine…

my A4 is going to this user: analogback (i know you are worried man, i feel you), but i think the newest the synth/module, the less problem youll have…

looking forward to it
I can"t see any problems that can"t be solved

dcsux · 2014-07-30T14:19:32.000Z

""analogback"":

hmm… so you can adjust the C voltage and voltage scale from this menu?
)

mais oui!

analogback · 2014-07-30T14:47:05.000Z

c’est fantastique!

Hexeract · 2014-07-30T22:18:05.000Z

""Mihajlo"":

I had no problem using slim phatty with cv (after it warms up), but had some wierd pot problems with Minitaur.
but that was after i installed minitaurs newest OS… back to Rev 2, and it was fine…

Yeah but like i said, i tested the synths against another CV sequencer and keyboard controller. The issue is not on the moog side of things.

Hexeract · 2014-07-30T22:19:03.000Z

""dcsux"":

Still sounds like you need to play with the V/Oct value on your A4 (ie. Function + CV A/B/C/D)

cv_page.jpg880×313 37.2 KB

Yep I’ve been in that menu.

Doesn’t that seem weird that I need to start sending uneven arbitrary voltages, from a digital unit that should be digitally calibrated to send the correct voltages?

to fix the scales i’ll have to change it to like .78 volts instead of 1v per octave, or something, I mean that’s just so crazy that a digital unit would need to be hacked like that to function properly.

Hexeract · 2014-07-30T22:21:03.000Z

""analogback"":

trimpots, get in there!

I think this may be the only solution. DO you know where i can find a layout of the inside of the analog four? Does it open in a way that allows for easy access to the pots? Do you know which pots control CV out?

apeirophobe · 2014-07-30T22:29:03.000Z

""Hexeract"":

[quote=“analogback”]trimpots, get in there!

I think this may be the only solution. DO you know where i can find a layout of the inside of the analog four? Does it open in a way that allows for easy access to the pots? Do you know which pots control CV out?[/quote]
So you would rather void your warranty and screw around with trim pots than adjust a couple of parameters from a menu? Have at it
Seriously, it only takes a couple of minutes to tune and I’ve only needed to do so once.

Hexeract · 2014-07-30T23:36:31.000Z

""apeirophobe"":

So you would rather void your warranty and screw around with trim pots than adjust a couple of parameters from a menu? Have at it
Seriously, it only takes a couple of minutes to tune and I’ve only needed to do so once.

Yeah you’re right.

I’ll mess with the voltage output and see if that works.

dcsux · 2014-07-31T06:33:15.000Z

[quote=“” apeirophobe""]

[quote=“Hexeract”][quote=“analogback”]trimpots, get in there!
[/quote]

I think this may be the only solution. DO you know where i can find a layout of the inside of the analog four? Does it open in a way that allows for easy access to the pots? Do you know which pots control CV out?[/quote]
So you would rather void your warranty and screw around with trim pots than adjust a couple of parameters from a menu? Have at it
Seriously, it only takes a couple of minutes to tune and I’ve only needed to do so once.[/quote]
And for the record, although it sounded way off with my slim phatty with the default settings (1v & 3v), once it had warmed up, and I had figured out how to tune it, the values I ended up with were something like 1.09v for v/oct and 2.98v for middle c. Not too far off (but I guess 0.09v/oct can make a big difference over a 8 octave range - >1semitone per octave).

Steevyhead · 2014-07-31T07:37:39.000Z

I had to do this with both my MS20 and Minibrute.
I had fired it up, and was so excited to get going, and once the sequences were playing I scratching my head as to why it sounded like absolute hell…

I started playing with things in the V/OCT section for each (as the synths were tuned pitch perfect to one another, and The values I ended up with were WAAAAAAY away from 1V/o.

The bright side… I wrote the numbers down, and now its a 30 second operation.

Good Luck man!

aleale62 · 2014-07-31T08:20:01.000Z

Did you already check the A4 CV out with a voltmeter?

ZenPunkHippy · 2014-07-31T08:33:23.000Z

The manual for the moog says that middle C should be at 3.00v, and v/octave should be 1.00. This is certainly not the case.

Despite what the Moog manual says (or suggests) the Slim Phatty does not operate at precisely 1volt / octave.

I think the correct setting is 0.97, but don’t take my word for it - you’ll need to experiment a bit to find the correct value. Once set, it should work as you expect.

There are a few threads on the Moog forum about it.

http://forum.moogmusic.com/viewtopic.php?f=7&t=11456

_mr · 2014-07-31T09:25:53.000Z

""Hexeract"":

[quote=“analogback”]trimpots, get in there!

I think this may be the only solution. DO you know where i can find a layout of the inside of the analog four? Does it open in a way that allows for easy access to the pots? Do you know which pots control CV out?[/quote]
There are no trimpots inside, except for an LCD contrast trimmer.

cpaxton · 2014-07-31T09:45:42.000Z

I have been thru quite a few moog synths…from a Taurus 2, thru the phatties and minitaur, voyagers and now sub and NONE of them have been 1v/ per octave! That measurement Is a guide line I find… Most of them ran at. 97v (the Taurus was the best…and oldest)
Oddly enough the best and closest 1vper octave synth I have found was an sh101

plusn · 2014-07-31T12:56:21.000Z

The A4 isnt the problem…the receiver of the CV output is the problem. And yes Moogs have a poor CV implementation. My (Ex-) Voyager also needed 0,97V. I wonder if the new Sub 37 has that fixed…