Mod Bus 1 & 2 Question

archer · Post by **archer** » Fri Dec 28, 2012 12:00 am

Hello,

This is my last issue I have regarding my Voyager Old School...

In Mod Bus 1 and 2, I'll have both of them at...

Source - OSC 1 Destination - Pitch Controller - Mod Wheel

But each Mod Bus does a slightly different modulation. For example, I'll turn the amount on Mod Bus 1 all the way up, and have 2 all the way down, then I'll turn the mod wheel all the way up, and the modulation will change the note I'm pressing in addition to adding the maximum amount of modulation.

But when I do the same thing on Mod Bus 2 instead of 1, a different note will be played when the mod wheel is all the way up. Not the same note at with mod bus 1, even though I'm playing the exact same key on the keyboard. It gets to like a higher pitch of something.

And the modulation is totally different on each Mod bus when I select osc 2 or 3 as the source, with pitch as the destination. Shouldn't they both do the exact same thing in terms of modulation and pitch shifting? It says in the manual that they both serve the EXACT same function. I just don't understand how they can sound different and do a different modulation if they are both on the EXACT same settings. What gives?

Sorry for blowing up the forums! I'm just freaking out.

stiiiiiiive · Post by **stiiiiiiive** » Fri Dec 28, 2012 6:28 am

Aaah Archer...

Don't freak out, here is the explanation for this and the pitch not being the sam with the oscillators freq knobs set to the very same angle etc: this is a-na-logue

Read: this is imperfect, inaccurate different from one unit to another, changing over time, over seasons and temperature. All of this staying moderate, huh?

And this is what most of us like it for!!

Trust your ears, my friend: when you begin turning a knob, close your eyes, and stop turning when what you ear is cool. No need for the visual position.

No offense, I'm just meaning: enjoy

Just Me · Post by **Just Me** » Fri Dec 28, 2012 9:34 am

Useing osc 1 or 2 as source will give you FM modulation. You are modulating with audio rate signals. Osc 3 at LO or LFO as source will give you results more in line with what you expect. Try and keep in mind that control voltages are just turning whatever knob you have assigned them to for you.

archer · Post by **archer** » Fri Dec 28, 2012 2:11 pm

Let me clarify:

When I have these settings, each Mod Bus is producing the same modulation effect, but each Mod Bus has a different depth amount.

All my oscillators are in unison, so it's probably not so much a tuning issue. But here's what's going on: I'll have Source=OSC 1, Destination=Pitch, and Control=Mod Wheel on BOTH mod busses. So the setting for each mod buss is the exact same.

I'll turn the mod wheel all the way up to test the depth of the modulation. I'll then turn the AMOUNT knob on Mod Bus 1 all the way up while holding a key. The effect that it has is that the key goes up in pitch. Then I'll turn Mod Bus 1 all the way down, and do the same thing to Mod Bus 2's AMOUNT knob, only this time, the pitch goes up HIGHER than the pitch when I turned the amount knob of Mod Bus 1 all the way up.

So in essence, the Modulation effect is the same; it is changing the pitch of the note I am playing. HOWEVER, the amount changed is different for each amount knob. It seems that the pitch is equal on both amount knobs when Mod buss 1's amount knob is at 10, and mod bus 2's amount knob is at 8. So basically, mod buss 2's amount knob goes up 2 more "lines" than mod buss 1's amount knob.

Differences also exist when I choose osc 2 as the source or osc 3; they are just different. I'll keep the destination as the pitch, but the depth of each amount knob is different.

So my question is, IS this how it's supposed to be? Like if I bought one new and took it out of the box, would it be this way? Shouldn't both Mod Busses do the EXACT same thing as each other when both on the same settings and with all the oscillators in unison.

Thanks!

stiiiiiiive · Post by **stiiiiiiive** » Fri Dec 28, 2012 2:40 pm

Hmm. Ok, no, our Voyager has a severe problem which the Moog techs will tell you it's normal and they cannot do anything to fix it.

Ok, I'll take it from you for a few hundreds kopecks.

archer · Post by **archer** » Fri Dec 28, 2012 4:09 pm

Here's a vid of what I'm talking about. Please take a look and let me know. Your answers so far have given me confidence, but here's a first-hand look. Thanks!

http://www.youtube.com/watch?v=qaeJOXDz ... e=youtu.be

thealien666 · Post by **thealien666** » Fri Dec 28, 2012 4:30 pm

Send it to me, I'll fix it for ya... You won't have to worry about it aaaanymore...

stiiiiiiive · Post by **stiiiiiiive** » Fri Dec 28, 2012 7:01 pm

Po po po!

Dibs on the broken Old School, sorry Alain!

Archer, everything is fine is the video.

thealien666 · Post by **thealien666** » Fri Dec 28, 2012 7:13 pm

Nah, you can have it stiiiiiiive... I had one at one point and got rid of it, after it had been repaired...

I prefer my simpler Mini D. It's more reliable. Mine is soon to be 38 years old and still going strong. Not like these new modern ones that break down all the time...

Kenneth · Post by **Kenneth** » Fri Dec 28, 2012 11:45 pm

thealien666 wrote:Nah, you can have it stiiiiiiive... I had one at one point and got rid of it, after it had been repaired...

I prefer my simpler Mini D. It's more reliable. Mine is soon to be 38 years old and still going strong. Not like these new modern ones that break down all the time...

Let's talk in thirty years, when my Old School is as old as your Mini is now, and your Mini is 68.

EMwhite · Post by **EMwhite** » Sat Dec 29, 2012 6:25 pm

Just fyi: I have the same exact 'condition' on my Old School. Never noticed it actually.

But try this: set DEST to Filter instead of pitch.

Notice the difference? Yeah, there is a difference but not as drastic. Could be a 'feature'. Maybe Mod bus 1 and Mod bus 2 use different pots (maybe one is linear and one is expo or one is 50K and one is 40K, not sure) But maybe not. Could be that there is some additive voltage on one bus vs. the other. Anybody with a New School Voyager care to try the same test out and report back?

Either way, I don't think this is an issue. Not sure if one of the ~25 blue tuning pots on the analog board calibrates the voltage for this but despite it appearing to be a very great difference, it is likely just a fraction of a volt. We are so used to hearing frequencies that something off by a few semitones is really noticeable. And fyi: mine is 2 semitones (yours sounds more like one) and all base frequencies are identical (so 32' or 1', still one whole not on mine). Voltage wise, that correlates to less than 1/10th of a volt.

With the exception of tuning your synth to A440, every other thing that you do is by ear so just continue to do that and don't worry about it.

stiiiiiiive · Post by **stiiiiiiive** » Sat Dec 29, 2012 6:59 pm

EMwhite wrote:With the exception of tuning your synth to A440, every other thing that you do is by ear so just continue to do that and don't worry about it.

This.

BTW on mine, the other bus is reaching higher modulation.

archer · Post by **archer** » Sun Dec 30, 2012 12:49 am

I was actually talking to a friend who's a huge Moog enthusiast, and he thought that the different mod depth between busses was a design flaw, and basically predicted that everyone's mod bus 2 gets more depth than 1. It's interesting to hear that some people are having their bus 1 have more depth than 2.

I would really like to hear feedback from people who have non-OS voyagers and see what they say.

EMwhite · Post by **EMwhite** » Mon Dec 31, 2012 1:43 pm

I took another look into this and wanted to add that while the busses are numbered 1 & 2 on the panel of the Old School, if you look on the Analog board for clues, you'll see that the two busses are labeled "WHEEL Bus" and "PEDAL Bus";

Clearly, on the Voyager, where modulation options are somewhat different, you can see that panel labels match the Analog board (which Voyager and Old School have in common) and if you look into the Voyager manual, you'll see very different text as compared to the Old School Manual.

Specifically, it talks about how the "Pedal Bus" is normal'ed to 5V so that if nothing is plugged into MOD1, it is as if the supply voltage is not being attenuated at all. With this original design and a likely different circuit path, it's not inconceivable that there may not be any calibration pots or factory procedures to have the two busses match.

Meanwhile, if you look at page 27 of the VOS manual, you'll see the following, curious note since the initial explanation of the Mod busses within the Old School manual mentions that the two busses are identical.

"MOD 1: The MOD 1 jack accepts an expression pedal or control voltage from 0 to 5 Volts. With nothing plugged into this jack, the voltage here is 5V (the ‘ON’ state).
MOD 2: The MOD 2 jack allows you to apply an external modulation source into the MOD busses. The input accepts an expression pedal or a control voltage of –5 to +5. With nothing plugged into this jack, the voltage here is 5V (the ‘ON’ state). When the Mod Buss SOURCE control is set to ‘ON/MOD2’, the voltage applied to this jack becomes the Modulation Source."

stiiiiiiive · Post by **stiiiiiiive** » Mon Dec 31, 2012 2:28 pm

Are you sure not to get confused between the MOD BUSSES 1/2 and the MOD jacks 1/2?

The busses indeed are identical, I mean they have the same options. The jacks are like described in the extract you just copied.

Isn't it?

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