In 3KB CONT, Osc 3 goes out of tune

The Moog Forum Minimoog Forum
1

Hi all,


This problem, my Voyager has had since the beginning, but I always thought I should just live with it. But in reading some posts, it seems this might be fixable.

Say I have Osc 1 and 3 on. They’re both in the same octave, have the same waveform and volume, and are in tune. Identical basically. Now when I throw the 3KB Cont switch to OFF, Osc 3 is supposed to become a drone. On mine, it also drops an octave, whch I think is normal.

What is not normal, is that it goes slightly sharp. But I can’t just lower Osc. 3, b/c it sort of jumps and interval. So I have to go below the pitch, then tune up.

What this amounts to, is that I can’t use 3KB CONT on the fly, performing live, etc. Or if I do, I have to quickly retune it.

The other problem is that if I turn 3KB CONT to “On” (non-drone mode), it’s now out of tune, and I again have to quickly retune.

Perhaps the problem stems from the fact that, for Osc 3 to be in tune with Osc 1, Osc three has to be at nearly +1. This has always been this way. In fact, I believe someone told me this was just something I was going to have to live with. Not really changeable.

Any help on this topic would be greatly appreciated.

The irony is that I once sent it into NC, with S. Dunnington’s assistance, to deal with another problem, which turned out to be just a matter of tweaking, not a hardware repair. I believe he said they did a re-tuning at that time. I’d hate to have to send her back in…

Finally, a side note. I’ve been drooling over the MF-104Z, if anybody out there is using it with the Voyager, let me know what you think!

Thanks in advance!
-brian

2

That’s normal.

When you switch 3 KB CONT to OFF, it’s changing from a VCO to a wide range LFO and (here’s the trick) it disconnects the keyboard CV from VCO3. It will not “remember” the last note you were playing. All Minimoogs, Voyager or vintage, do that.

I bought two MF104s (original model) before the Voyager was released, not knowing it was going to have stereo outputs. Filter sweeps with the touchpad (esp with S&H FX) are pretty neat with stereo MF104s :smiley:

3

If I’m not confused, I believe Osc 3 turns to a LFO when “3FREQ” is turned to Low, in which instance, it would be inaudible. I’m talking about when “3FREQ” is on Hi, and Osc 3 is audible. I understand the part about it disengaging from the keyboard, which is a function of 3 KB CONT. Any others?..

4

Doesn’t matter whether 3FREQ is on LO or HI.

5

Hi brianfores,

at my MMV the pitch of OSC3 equals a ‘sharp’ C#4 (some ct above MIDI note number ‘3d’ hex or ‘61’ decimal) if 3 KB CONT is OFF.

To detect this, OSC 3 was tuned firstly (using its knob FREQUENCY) while 3 KB CONT was ON. Then I switched 3 KB CONT to its OFF position.

Is this true for your MMV?