1V/Oct scaling on the MF-103 LFO

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Vsyevolod
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1V/Oct scaling on the MF-103 LFO

Post by Vsyevolod » Thu Mar 29, 2012 5:20 pm

Hi all,

Long time modular user, first time poster.

I just recently traded my Hartmann Neuron for a Voyager, 101, 102, 103, 107, CP, and VX modules. Quite a nice trade for both of us and I'm very happy to be back in the world of patchcords.

So here's what I'm trying to do. I'm running the 'Mixer Out/Filter In' from and to the Voyager through all my pedals (101, 102, 103, and 107). I have the VX and CP hooked up as well. When I take the 'Keyboard Pitch' out from the VX and plug it into the 'Rate In' on the 103 Phaser, I get almost-but-not-quite 1V/Oct. I'm trying to move the LFO frequency (set to high) in step with the keyboard frequency. I'm starting with the low C on the Voyager because it's 0 volts and a seemingly good place to start the calibration process. I've tried running the 'Keyboard Pitch' voltage through an attenuator as well as through the Four-Input Mixer on the CP. So far no luck. I called Tech Support at Moog and they seemed stumped by it as well. He didn't know if there was an internal calibration trim pot on the LFO input (which would be ideal...). Of course I could re-scale the keyboard out from my Voyager but at the cost of messing up my internal keyboard tracking.

So has anyone run into this issue yet? And found a way to scale the keyboard voltage to LFO parameters? I'm thinking that I'd like to apply this kind of patch to other LFO's on other MF boxes.

Thanks,

Stephen




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EricK
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Re: 1V/Oct scaling on the MF-103 LFO

Post by EricK » Fri Mar 30, 2012 11:43 am

I've never tried to control the LFO but you can do some interestingly musical things attempting to use the phaser as an osc via the sweep input. It won't track 1V/Oct either, though. Sorry I wasn't more help though.
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ebo
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Re: 1V/Oct scaling on the MF-103 LFO

Post by ebo » Mon Apr 02, 2012 12:59 pm

I think the scaling is 0.6v ,it works with the MP201 or
http://youtu.be/wqBe36pKnRQ
ebo

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Vsyevolod
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Re: 1V/Oct scaling on the MF-103 LFO

Post by Vsyevolod » Mon Apr 09, 2012 5:58 pm

Thanks, that video confirmed what I have heard so far. That the Moogerfooger boxes do not have any way of scaling them to 1V/oct. With the exception of the 107 FreqBox, which seems to have been 'roughly' set for 1V/oct. It would be nice if the CP-251 had a CV processor where you could alter the scaling to taste. I do not have the MP-201 pedal, so I don't know if it is capable of such CV scaling magic.

Stephen




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jeepo
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Re: 1V/Oct scaling on the MF-103 LFO

Post by jeepo » Mon Apr 09, 2012 9:10 pm

all you need is a simple attenuator, such as a pot or two to decrease the scale.
Stage II, MF-102, MF-105m, MF-107, paia theremin, akai s2000, yamaha pss 680, yamaha cp 25, and other stuff

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Vsyevolod
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Re: 1V/Oct scaling on the MF-103 LFO

Post by Vsyevolod » Tue Apr 10, 2012 12:33 am

Yes, though in this case, you need to amplify the scale, not attenuate it. Specifically, from .6 V/oct. to 1V/oct. There are attenuators to be had on both the VX and CP modules. No modules to increase the voltage scale.

Stephen




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jeepo
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Re: 1V/Oct scaling on the MF-103 LFO

Post by jeepo » Tue Apr 10, 2012 7:06 am

If your source is 1v/octave it can be attenuated down to 0.6v/oct.
Stage II, MF-102, MF-105m, MF-107, paia theremin, akai s2000, yamaha pss 680, yamaha cp 25, and other stuff

Sir Nose
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Re: 1V/Oct scaling on the MF-103 LFO

Post by Sir Nose » Tue Apr 10, 2012 11:38 am

Vsyevolod wrote:Yes, though in this case, you need to amplify the scale, not attenuate it. Specifically, from .6 V/oct. to 1V/oct. There are attenuators to be had on both the VX and CP modules. No modules to increase the voltage scale.

Stephen




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You can use the mixer. Split the .6V/oct into 2 signal using a multiple or splitter. The current halves, but the voltage of each will be .6v/oct. Send them both to the mixer. Now you should have 1 signal at 1.2V/oct. Attenuate down to 1v/oct.


Also, many cheap linear boost pedals will work. They are designed for an AC sound source, but many will work for DC CV. I say cheap because there's a chance you could kill the pedal, most likely not as they are usually simple circuits.

EricK
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Re: 1V/Oct scaling on the MF-103 LFO

Post by EricK » Tue Apr 10, 2012 2:29 pm

I did this song with the phaser as an Osc.
http://soundcloud.com/rhythmicons/noise
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jeepo
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Re: 1V/Oct scaling on the MF-103 LFO

Post by jeepo » Tue Apr 10, 2012 3:25 pm

I just want to carify the issue you are having. When you play an octave on the keyboard. Is the 103's osc sharp or flat?
Stage II, MF-102, MF-105m, MF-107, paia theremin, akai s2000, yamaha pss 680, yamaha cp 25, and other stuff

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Vsyevolod
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Re: 1V/Oct scaling on the MF-103 LFO

Post by Vsyevolod » Wed Apr 11, 2012 1:44 am

jeepo wrote:I just want to clarify the issue you are having. When you play an octave on the keyboard, is the 103's osc sharp or flat?
I'm using the LFO from the 103 in the audio range (high). It is flat compared to the keyboard.

My initial impulse came from tuning the audio rate LFO to a related frequency from the Voyager. I wanted this particular timbre to track the tones from the keyboard cause it was pretty bitchin' sounding.

I'll have to try splitting then remixing a voltage. My inner logic tells me it won't work, but I'll certainly try it first thing tomorrow.

Stephen




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Vsyevolod
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Re: 1V/Oct scaling on the MF-103 LFO

Post by Vsyevolod » Wed Apr 11, 2012 4:03 pm

I took the Key Voltage out from the VX module, ran it into a mult, took two outputs from that mult and ran it into the FourInput mixer on the CP. With 'Offset' and attenuation controls, I was able to get 1V/oct tracking for about two octaves, maybe two and a half. The top octave of the keyboard never seems to scale well, especially the top half octave. And I've experimented with dropping the pitch of the 103 just to make sure I'm not 'topping out' on the upper end of its range.

So anyway, thanks all for the input. I still haven't fully wrapped my head around the FourInput Mixer on the CP. I was able to get the 103 to track almost the entire keyboard. My guess is that the lack of stable tracking lies within the 103 more than it does the Voyager.

This is my first week or two with the Voyager + Foogers. I was able to find the missing Foogers in my collection on Craigslist and eBay and they should be arriving later this week. Gotta love the quality of sound...

Stephen




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