Korg Forums

Hi there,

hope you can help me: Im getting Oscillator Drift when controlling the Odyssey with CV/Gate (from an Analog Four in that case). This is bad! How can i get rid of this?

Im sending Gate with 5V and i use Pitch V/Oct for CV. It works, its also pretty tuning stable, but i get this damn Oscillator Drift for BOTH Waves. Does anybody know how i can get rid of this?

Thanks in advance
subbz2k

Ok, i get closer.

I get the issue above when i send CV over the Tip and Gate over the Ring. I switched this on the Analog Four (CV over Ring and Gate over Tip) and now it's stable. But interestingly: When i switch it back the way it was (CV on the Tip and Gate on the Ring) it stays stable anyway.

Is this a known issue with the Odyssey?

OK, scratch that

It only worked because at the time of my second test i only had one oscillator active. So its either way around: I have Oscillator Drift when using both Oscillators and not having them Sync'ed.

Can you help me out?

How much does the Arp Odyssey output drift by? A semitone, an octave? The problem can be isolated by monitoring the output of the Analog Four with a voltmeter, whilst holding a key down. If it is stable, then the issue could well be with the Arp Odyssey. Before coming to any conclusions, check lead continuity, and make sure the contacts to the CV inputs and outputs are clean. Does wiggling the CV lead and its jacks cause any variations in oscillator frequency?

.

Hi,

Please elaborate a bit on 'oscillator drift'.
Is it the abslotute tuning of one or both oscillators that drifts away (to a higher or lower pitch)?
Or do you refer to the fading and swelling effect when both oscillators are on but not synced?

Bye

Hey there,

many thanks for your reply Guys.

Ok, lets make a bit clearer what i mean. I dont have an issue with Tuning here. The Oscillators are both stable in terms of tuning. If i hit a C i get a C on both of them - over several octaves, that works very well.

With "Oscillator Drift" i mean the following: Take a synth, set it's Oscillator to a Square Wave and do PWM at a slow rate. The Wave is thinning out and comes back again. This is what happens. It equals to the following sentence from you @OpAmp:

Or do you refer to the fading and swelling effect when both oscillators are on but not synced?

This is basically exactly what happens. If i only use one Oscillator, everythings fine. If i use both and Sync them, everythings fine too. But the moment they run independent from each other, that "swelling" occurs.

Is there a way to get rid of that? I dont have this when playing it over MIDI/USB. It only happens with CV/Gate. I thought a little bit about that already; can it be that this has to do with the Duophonic nature of the Odyssey? So, one Oscillator receives those Signals and the other one doesnt? Or not really?! Its my first contact with CV/Gate i must admit So maybe i did not get how all of that works yet.

Thanks for your help
subbz2k

Hi,

Well in fact, I'm surprised it does not fade and swell using USB/MIDI.

Here is my take. The Odissey consists of two analog oscillators. You may fine tune them as good as possible, there will always be a very small difference in frequency between both of them. That small difference will cause the fading and swelling. Always. The phases of both oscillators start to run away from each other and will over time amplify each other or cancel each other.

What can you do about that to avoid it? That's why they introduces the 'sync'. The second oscillator is 'reset' at the moment the first one starts a new cycle, making sure that the frequency of the second oscillator is 'locked' to the first one and this does avoid the fading/swelling.

AFAIK, using CV/GATE you will not be able to explore the duophonic nature of the Odissey. Because you would need a second set of inputs for that in order to play 2 different notes at the same time.

Have fun.

Thanks for this clarification OpAmp.

Nope, this doesnt happen via MIDI/USB. Thats why i find it so strange. It also doesnt happen if played with the Keyboard. You can see tons of videos out there (including the excellent Video from Sonicstate) and they dont show this behaviour too. So i assume that the chip built into the Odyssey (the one handling MIDI/USB) takes care about that.

Ok, so everythings fine with my unit, great.

But i have to correct you now You can make use of the Duophonic Nature via CV/Gate of the Odyssey. With the Analog Four it works. Just send two different CV Signals over one cable The Input is stereo, it receives on the Tip AND the Ring. I tried it out today because at first i thought that this might solve the Drift. It helps a little indeed, the Oscillators are slightly more stable that way. But it doesnt completely solve it. What it does however: I can send two different Pitch Values and get the Duophonic Nature back that way. On the Analog Four you can define what you send, so you can easily send CV V/Oct two times if you want. I have the CV/Audio Kit from Elektron which splits the Stereo Out from the A4 into two independent mono signals. Now i only used the Audio Cable for my Volca Sample (Mini Jack stereo to 2x TRS Jacks), pluck it into the CV Kit and plug its Stereo Mini Jack into the CV In of the Odyssey. Guess that a TRS Stereo to Mini Jack Stereo Cable would do the same thing but i dont have these.

Try it out, it works perfectly And it makes the Oscillators a little bit more stable, but they dont get as stable as with MIDI/USB unfortunately. Only Gate is received mono from the Odyssey as it seems. Two Gate signals dont make a difference at least. One cancels out the other as it seems. But two CV Signals, one Stereo Cable for Duophonic Play works.

Hi subbz2k,

Ok. Though I still see in the manual that the CV and Gate jacks are monaural... So I'm a bit confused now.

Bye.

Yep, it is possible but the Tuning for the first or the second oscillator (depending on how you wire it) will be a bit odd. You need a sequencer that allows you to send precise Pitch Values on a per Step basis; like the Analog Four does

I'm in the making of a Video regarding this. It should be online tomorrow in the Evening. I will link it here to show you how it works

Till tomorrow

Ok, it took a bit longer to get the Video done. Here it is:

https://youtu.be/YmyfqJUm8gc

As you can see: Its possible, but its a bit fiddly

Cool! You really discovered an eastern egg according to me.

Why does Korg not mention this in the manual?

Ciao