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OB-6 tuning problem

OB-6 tuning problem
« on: May 19, 2019, 07:35:39 PM »
Hi guys,

I'm having a problem with my OB-6 and finally had a chance to get a sound file to capture it. I have a single held note that, as you can hear, goes in and out of tune by a semitone at differently recurring intervals. I captured this in manual mode with no LFO or XMOD enabled, or any effects. This doesn't happen when I first power the unit on, but will start to happen once it has been left on for a couple of hours. I have run the tuning procedure multiple times.

In the accompanying sound file I have both oscillators and the sub running, then individually OSC1, OSC2, and SUB, it happens in all cases.

I also tried changing from manual mode to a preset once this behavior started happening and it happens with the presets as well.

Of course I do expect some VCO drift but I suspect this is more than that. Has anyone seen this, and what did you do to get around it? I also have a P6, which has never exhibited this behavior.


Just saw this topic:,3530.0.html

Looks like deleting the tuning tables and rerunning the procedure may have helped. Will keep an eye on it. Probably can delete this one.
« Last Edit: May 19, 2019, 07:48:46 PM by sean »

Re: OB-6 tuning problem
« Reply #1 on: May 20, 2019, 08:47:41 PM »
Mine (keyboard version) does the same thing. I run the calibrate command and it gets better. The module version I had was rock solid. Hmmm...
OB-6, Prophet XL, Hammond XK-5, Crumar Seven, Moog Taurus III, Vermona PerFourMer MKII, Korg Kronos 61, Memotron M2D, Kawai ES110, Pearl Mimic Pro, Chapman Stick 10-String, ISP Beta Bass DSP, Roland GR-55, Roland VG-99, Boss GP-10

Re: OB-6 tuning problem
« Reply #2 on: May 22, 2019, 03:07:19 PM »
I have seen some similarly odd 'detuning' phenomena...often when I'm running the OB-6 from an external MIDI source. I'm suspecting it's some sort of NRPN or CC glitch. If I just turn the synth off and then on again it disappears.
DSI OB-6, Nord Electro 3HP & 6HP, Roland SoundCanvas SC55mkii, Beatstep Pro, MPD18 (+mpcstuff), Roland TD-4 V-drums, Fender-Rhodes Stage MK1, Reaper, plus dozens of acoustic instruments and mikes.