Minimoog Sync Mod

[thealien666]

As I wrote in my previous post, VCO1 is always the master, to which VCO2 and/or VCO3 synchronize to. Simple as that.
In other words, no matter what the frequency of VCO2 is, it will be restarted by the frequency of VCO1. Same thing for VCO3 independently of VCO2.

It's a fixed configuration, so VCO1 could never be a slave, and is always the master.

That's why the "sync effect" will always work best when VCO1's frequency is lower than that of the slaves. Moreover, the "sync effect" will only be heard when changing the frequency of the slaves manually, since there is no envelope, or LFO (VCO3 used in an LFO configuration) routing to the pitch of either VCO2 or VCO3 independently of VCO1.

BTW, for those with a newer osc board (the one with more than 7 adjustment trimpots), I don't know of the sync mod shown on Kevin's Synthfool page for it would work. As Kevin himself wrote a disclaimer that he did not try them out himself. I just know that the one for the "regular" osc board works fine in my Mini.

Top one in the picture below is the most common, below that is the "newer" version.


Actually it might look more like this one (note the ua726 round chips instead of the DIP package of a CA3046 with a Tempco glued on top, as the ua726 as already a integrated thermostat system inside it)
But you get the idea that it has more than 7 trimpots also.

[megavoice]

Thank you SO MUCH
The discussion will go on. My tech stays very cool about the mod of the newer board. He said on the iolder one there's more to know and not so easy. I cannot comment this.
But with your detailed descriptions we'll gonna succeed at the end....Wonderful

[thealien666]

You're welcome.

Also be aware that, since the original VCO circuits were not designed to be hard synced, the behavior of the "hard sync effect" might not be as smooth as on synthesizers with that feature integrated into their design.
Meaning that, when the slave oscillator (VCO2 or 3) is "restarted" by VCO1's frequency, there is a very brief delay until it starts oscillating again (very noticeable when VCO1 is set to the Lo range). The result is a sort of "harsh" or "crude" hard sync effect at audio frequencies. But very usable nonetheless.

[megavoice]

You're welcome.

Also be aware that, since the original VCO circuits were not designed to be hard synced, the behavior of the "hard sync effect" might not be as smooth as on synthesizers with that feature integrated into their design.
Meaning that, when the slave oscillator (VCO2 or 3) is "restarted" by VCO1's frequency, there is a very brief delay until it starts oscillating again (very noticeable when VCO1 is set to the Lo range). The result is a sort of "harsh" or "crude" hard sync effect at audio frequencies. But very usable nonetheless.

Fine, I'm going to add this.
But I`ve also to tell you,that my tech is some kind of weird of your former description of the 3 oscillator mod (???). He says that your configuration makes no sense and there`s no tonal benefit to achieve.
Well, I`m still not satisfied with this judgement and will print your description and take it home to talk about again.
But he and I we`re still have the same opinion that my Sync-Synced (Double Sync Version, the synced oscillator 2 is the provider and Nr. 3 will be the double synced)....... might be interesting.
But it's questionable if we ever try, as ther`re SO MANY wires at the end and may lead to confusion.....

Well I`m thinking about, and I'll dicide for the simple solution as I described initially, 2 oscillators with the Filtor Contour, but independently !!! regulated with a pot. "Sweep Depth".
Today I bought a pot with a intigrated switch, so that I don't need an additional toggle and can use that small place best after unscrewing one of the power supply jacks.
That`s it.
The electronic mod I`ll do also by myself with instructions of my tech on the phone.
He said he also doesn`t care of that bug you've told about, as he absolutely does know how to do the job precisely.

[slirak]

The point of having both VCO 2 and 3 independently syncable to VCO 1 is this:
* VCO 3 can be used for frequency modulation of VCO1 and 2. You might like to be able to do that while VCO 2 is synced to VCO 1. So that's why you might like to have only VCO 2 synced to VCO 1.
* VCO 3 can be set to a fixed frequency (OSC Control Off). Syncing VCO 3 to VCO 1, with VCO 3 set to a fixed frequency, can create unique timbres. So that's why you might like to have VCO 3 synced to VCO 1, either on its own, or with VCO 2 synced as well.

[megavoice]

Well, I read Alains description more carefully yesterday and got it whithin a minute.
Yes, it`s quite clear now. But either sync of osc 2 or osc 3 is fixed at every time as you set it.
But sync in General becomes most interesting when it`s starts moving, beeing swept from a modulation source
like Contour or LFO.
It`s just like having a motorbike and standing still while turning on the gas when having only the sync mode fixed.

As for the bug, there isn`t anyone, it was only a misunderstanding.....

[thealien666]

You got it.

The only drawback of doing such a mod on a Minimoog D, and has demotivated some people of going ahead and installing it, is the fact that he Mini doesn't allow the modulation of either VCO 2 or 3 individually, relative to VCO 1, to get the classic "hard sync" effect. Although you can still get some "new waveforms" out of them by having the sync at fixed settings. And also use it the way slirak (thanks) mentioned.

Some people went ahead and added other mods still, to allow new routings of the envelope and LFO (VCO3 in Lo mode) to VCO 2 to get the "traditional" hard sync effect. But that is a much more involved mod that I wasn't willing to do.

I just wanted to be able to get "organ type" waveforms (without any detuning between VCOs) out of my Mini.

[megavoice]

You got it.

The only drawback of doing such a mod on a Minimoog D, and has demotivated some people of going ahead and installing it, is the fact that he Mini doesn't allow the modulation of either VCO 2 or 3 individually, relative to VCO 1, to get the classic "hard sync" effect. Although you can still get some "new waveforms" out of them by having the sync at fixed settings. And also use it the way slirak (thanks) mentioned.

Some people went ahead and added other mods still, to allow new routings of the envelope and LFO (VCO3 in Lo mode) to VCO 2 to get the "traditional" hard sync effect. But that is a much more involved mod that I wasn't willing to do.

I just wanted to be able to get "organ type" waveforms (without any detuning between VCOs) out of my Mini.

Interesting.........

[megavoice]

You got it.

The only drawback of doing such a mod on a Minimoog D, and has demotivated some people of going ahead and installing it, is the fact that he Mini doesn't allow the modulation of either VCO 2 or 3 individually, relative to VCO 1, to get the classic "hard sync" effect. Although you can still get some "new waveforms" out of them by having the sync at fixed settings. And also use it the way slirak (thanks) mentioned.

Some people went ahead and added other mods still, to allow new routings of the envelope and LFO (VCO3 in Lo mode) to VCO 2 to get the "traditional" hard sync effect. But that is a much more involved mod that I wasn't willing to do.

I just wanted to be able to get "organ type" waveforms (without any detuning between VCOs) out of my Mini.

Referring to the newer board my tech doesn`t see any problems to proceed the "hard-sync" mod (???)
He´s absolutely convinced about to succeed in perfectly. He already had one on his table with that sync.
I`m still talking about the most simple one, osc 1 to osc 2, swept by Contour.
I don`t hope to get a "Delay" after..........

[thealien666]

I`m still talking about the most simple one, osc 1 to osc 2, swept by Contour.
I don`t hope to get a "Delay" after..........

Swept by Contour ? I think not.
Unless your tech does another modification to route the output of either the Filter Contour or Loudness Contour to the pitch of OSC 2, it won't happen.
On a stock Minimoog there is no way to send either of those two modulation sources to OSC2, unless an additional mod, independently of the hard sync mod, is done expressly for that.

I don't quite understand your last statement ? You hope to get your Mini back from your tech fast, or you hope that there will be no delay in the sound after the mods are done ? I'm confused...

[megavoice]

I`m still talking about the most simple one, osc 1 to osc 2, swept by Contour.
I don`t hope to get a "Delay" after..........

Swept by Contour ? I think not.
Unless your tech does another modification to route the output of either the Filter Contour or Loudness Contour to the pitch of OSC 2, it won't happen.
On a stock Minimoog there is no way to send either of those two modulation sources to OSC2, unless an additional mod, independently of the hard sync mod, is done expressly for that.

I don't quite understand your last statement ? You hope to get your Mini back from your tech fast, or you hope that there will be no delay in the sound after the mods are done ? I'm confused...

Now wait and see, I`m going to report about the result, and if you like I`ll describe the way and procedure only for you, but my tech has SO extraordinary much work to do that it will last for weeks or months.
Now he`s still on my Polypedal for completely rewiring. It`s just like dis- and reassembling a whole Polymoog......and the piles of Memorymoogs and many, many other synths.........

[thealien666]

Ah, okay. I understand now. Your tech IS going to mod your Mini so you have the possibility of using a contour generator as a modulation source.
And it'll take him a long time to do because he's already backlogged...

Fine. Keep us posted !

[megavoice]

Ah, okay. I understand now. Your tech IS going to mod your Mini so you have the possibility of using a contour generator as a modulation source.
And it'll take him a long time to do because he's already backlogged...

Fine. Keep us posted !

Exactly, but I`m trying to do the mod by my own as don`t want to send it a lot of kilometers through the whole Republic.
I`m going to be instructed on the phone.
As for your previous question, I meant the "Delay" you`ve talked about as an unexpected und not wanted appearance.
But we`ll see what will happen.........In worst case the machine will start smoking after switching on.....