OB-6 tuning problem

[sean]

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: https://forum.sequential.com/index.php/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.

[Perilous]

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...

[shmuelyosef]

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.