Sub 37 - Mod 1, VCA level

[Leighzi88]

Hi guys,

First post here ... Just got my Sub 37 and LOVE it!! (First Moog synth too.)

I was playing with my first init patch and had the square wave modulating the VCA level (tremolo effect) and noticed that it only worked with negative mod amt, not positive mod amt. I thought this was an issue, but then changed to triangle wave and it works both +ve and -ve ... so it's all good.

Just wondering though, why does +ve mod amt not have an effect on square wave modulation of VCA? (sorry if this is a noob question).

Cheers from Melbourne!

[_DemonDan_]

I was playing with my first init patch and had the square wave modulating the VCA level (tremolo effect) and noticed that it only worked with negative mod amt, not positive mod amt. I thought this was an issue, but then changed to triangle wave and it works both +ve and -ve ... so it's all good. Just wondering though, why does +ve mod amt not have an effect on square wave modulation of VCA? (sorry if this is a noob question).

G'day Leighzi,

I recently posted a thread called Sub 37 MOD Destination Tips:
http://forum.moogmusic.com/viewtopic.php?f=7&t=22108

It helps explain the additive and multiplicitive properties of the MOD busses.

#2 should help your above question, along with the fact that the Square Wave LFO is positive only (as opposed to bi-directional).

In a nutshell... If you want to modulate a VCA in the Mixer with a Square Wave LFO (or anything that's primarily positive), you're going to need to negate other sources that are also trying to push the VCA open. In other words, turn the desired VCA (like OSC 1 LEV) all the way down in the MIXER before you try modulating it with the Square Wave. Otherwise you're just trying to open something that's already open.

[Leighzi88]

Thanks very much DD, that makes great sense!

[bujo]

Hi DeamonDan, your tips are great advices! Thanks a lot, I didn't figure the square wave was only positive! I read your "Sub 37 MOD Destination Tips" thread and that's awesome BUT STILL... I find it doesn't resolve the problem described here. I tried setting the destination to "PGM > OSC1 level", I turned down the OSC1 in the mixer and it effectively worked with a positive MOD AMT. Awesome! But this behaviour is not effective when we use "VCA level" as a destination. I tried turning all the knobs down in the mixer, turning the output volume down...

What am I missing?

[MacAquinas]

G'day Leighzi,

I recently posted a thread called Sub 37 MOD Destination Tips:
http://forum.moogmusic.com/viewtopic.php?f=7&t=22108

It helps explain the additive and multiplicitive properties of the MOD busses.

#2 should help your above question, along with the fact that the Square Wave LFO is positive only (as opposed to bi-directional).

In a nutshell... If you want to modulate a VCA in the Mixer with a Square Wave LFO (or anything that's primarily positive), you're going to need to negate other sources that are also trying to push the VCA open. In other words, turn the desired VCA (like OSC 1 LEV) all the way down in the MIXER before you try modulating it with the Square Wave. Otherwise you're just trying to open something that's already open.

Dan your posts are always tremendously helpful and informative. Have you considered,or would you, making a Sub 37 Missing Manual? I know I would be willing to pay for your insight and tips and gain from your understanding . Thanks for your great posts.

[_DemonDan_]

BUT STILL... I find it doesn't resolve the problem described here. I tried setting the destination to "PGM > OSC1 level", I turned down the OSC1 in the mixer and it effectively worked with a positive MOD AMT. Awesome! But this behaviour is not effective when we use "VCA level" as a destination. I tried turning all the knobs down in the mixer, turning the output volume down... What am I missing?

Hi bujo,

Before I even turned on the Sub 37, I was certain that the reason you couldn't positively modulate the VCA Level was because the SUSTAIN Level of the AMPLIFIER EG was pushing the VCA up and needed to be at zero before you could modulate it positively between full on and silence.

But no... that wasn't it. (And I was pretty sure that was going to be the solution.) 

So I was actually typing this sentence:
"I have to say that the VCA LEVEL seems to stay at 100%",
which suddenly reminded me of the PRESET VOL: 100% parameter in the PRESET EDIT menu.

Sure enough, as I lowered the percentage of PRESET VOL, I became able to positively modulate the VCA Level. 

But... As I lowered the PRESET VOL below 50%, the ability of the LFO to bring the volume back up to full started dropping off, to the point that, when PRESET VOL = 0%, the LFO was unable to bring the VCA Level above silence. 

Summary: Lowering PRESET VOL does allow you to positively modulate the MOD DESTINATION called VCA LEVEL, but it only seems to be able to push it halfway up each time.

I honestly don't know if this is a bug, a feature, or an unavoidable necessity for reasons don't know.
I will dig deeper.

Interesting find bujo!

[bujo]

Thanks DemonDan for shedding light upon this! Effectively, the first time I encountered this issue, I looked for the VCA level knob and... it wasn't there (despite all the other knobs we love to actually BE there). It's tough to imagine that it was intended to be like that but I know that they must work hard to try fixing all kind of little details in the shop every days. I hope they're gonna fall on this one eventually (though it's not my main concern... ).