Korg Forums

[Nemo0]

Hi.
New to analogue synths (synths in general) but i think my unit has a problem.

I start with an Init Patch and set the synth to "Load PNL"

I open the mixer fully on both oscillators, both being set identically for type, pitch, octave, shape - and the combined signal oscillates on the scope, as does the combined sound.

When I turn off the mixer on Osc2, leaving Osc1 at full vol, the signal assumes the shape of the waveform, and remains constant - the shape of the waveform remains static whilst a note is held.

But when I turn off the mixer for Osc1, and open Osc2 to full vol, the signal assumes the shape of the set waveform, but tracks either left or right, and if I repeatedly strike a key, it stops moving sideways, and after another press starts moving again. Different notes change direction of the tracking.

When I engage the Sync switch ( Osc2 open Osc1 closed, eg.Sq wave on both) the shape of the resultant sq wave gets a notch cut out of the top of the waveform.

Cutoff is at max, and resonance at zero, cross mod depth at zero, shape at zero for both osc. Poly voice mode.

I've tried a global reset, and a tuning reset. No change

[Nemo0]

Its like I have cross modulation going on between the oscillators, when CM depth is turned to zero. If I modify VCO1 (mixer at zero) by changing its octave, the mixer output of VCO2 (at max) changes direction and shape, esp at the highest octave.

If I play and hold two notes together, the resultant wave 'vibrates' (oscillates?) on either/both VCOs, but the VCO2 oscillates faster than VCO1.

The result is that if mix the two identically set oscillators together (with no modulation set via the LFO, no cross mod, no sync, no ring) I get a different sound with every key press of the same note, and different again when different notes are played. The only thing i can do to keep it stable is play via VCO1 only

Surely thats not normal? I don't know if this what the whole VCO vs DCO debate is all about but im thinking I probs need to get this unit serviced.

Can someone please confirm this is/isnt supposed to be happening ?

[slug]

To me it sounds like they are just out of tune, and you will probably see the tuning offset change slightly as component temperatures change after starting to use it after power up.

It can be difficult to tune VCO analog oscillators perfectly, especially on Minilogue which although has high resolution encoders, they still only have quantised steps to tune to. If other musicians such as guitarists could only tune their instruments in quantised steps most would balk at the suggestion!

Even top dollar Sequential Take 5/Prophet 5 VCOs have a very similar drift between OSC 1/2 that you describe, while DCOs like Behringer Deepmind are be rock solid. My KARP 2600 is probably my most stable analog I have, and that has 60mm fine tune faders which certainly help as it requires really tiny amounts of pressure to try nudge it into tune (almost!) perfectly.

Thats my experience anyway

[Nemo0]

[slug]

Minilogue and XD do exactly the same as you report where VCO2 tracks across the oscilloscope based on how out of tune with VCO1 is. I dont know how oscilloscopes work but I can only guess it references VCO1 as the master and so locks that, with VCO2 showing the relative difference.

On Minilogue XD if you compare say saw VCO1 with saw of the Multi Oscillator which is digital so should be completely solid, the movement is still there, just less pronounced. And while Multi OSC should be solid, it moves in the oscilloscope against VCO1, even though it is probably the analog VCO1 that is drifting.

I feel as if when DCO became popular it was a revelation because suddenly everything could be perfectly in tune, and then 20 years later everyone discovered how good out of tune analog things can sound creating the analog renaissance. Taken to the extereme we have no things like on the Prophet 5 "vintage" knob that lets you dial in the amount of instability in tuning and other components (particularly interesting to me how it changes the envelope response per voice - amazing for arpeggios).

Perfection is good when you need it, but it isn't necessarily the most interesting!

[Nemo0]

Ahh ok - thanks very much for confirming this is normal behaviour for the minilogue. At 90$ per hr + parts I was dreading having to get it repaired.

And yes - the oscilloscope does appear to show changes in the wave that one can't actually hear, so that can be a bit confusing for a newb like myself.

[synthpeter]

It's very much the same on the Monologue, its oscilloscope triggers on the start of a VCO1 cycle. By the way, it's also how a dedicated oscilloscope works, where you have a separate signal input and a trigger input. Without a trigger, the scope would have no idea where to start displaying the incoming signal.

[Nemo0]

Interesting - thanks Peter.

I'd figured theres a good reason that Korg decided to put one into the unit, but I just haven't used subtractive synthesis before, being a lowly six stringer up until now - so i'm not sure what im seeing or how to use it - hence why i misunderstood what i was seeing ...

I really regret not having learned keys until now, but my god, the vsts/midi controllers that are available now - well, lets say it has given me a whole new outlook on music creation. Old dog and new tricks...

Figuring out how to get all these synths ( minlogue xd and wavestate), controllers, DAW, interfaces etc and vsts to talk to each other via midi is quite the learning curve. What a godsend the internet, forums and Youtube is for learning all this stuff.
Cheers