The Behringer Odyssey teardown and calibration of the power supply

This is a quick video about how to open up the Behringer Odyssey, and how to check and adjust the Power Supply's voltages.
Analog synths drift over time, and might need calibration from time to time.
But before you start to adjust or calibrate at synth, always check the voltages and adjust them first.
The Behringer Odyssey have two voltage rails internally, +15 volts and a -15 volts. And they should read exactly plus and minus 15.00 with a high quality multimeter.
And the Odyssey's bottom plate with the keyboard assembly has to be removed first.
The Behringer Odyssey and Arp Odyssey are very similar in many aspects when calibrating, but there are some differences when it comes to physical things and how to take it apart and how the power supply works. And there's no main voltages inside the Behringer.
If adjust the voltages, you'll need a good quality multimeter.

[@Smethurst82]

Great video and your second video showing the trim and scale really helped but I am having some problems with the Octave Scaling for the lower octaves of the B-Arp. Do you think the voltages might be the issue for that?

[@tukler2]

Thank you! I'd definitely check the voltages, even a cheep multimeter would do the job. Pitch calibration and scaling can be tricky and it's hard to get it perfect, it helps if you're stubborn and don't give up. But if the voltages are out of spec the scaling will never be perfekt. Keep in mind that this is old analog technology and it will probably never be 100%. Good luck!

[@Smethurst82]

@@tukler2 I'd already picked up a multimeter in preparation and with a lot of hours and plenty of perseverance (stubbornness) I believe I've solved the issue. Using a mix of your techniques and some trial and error with the VCO1 offset + the lower octave scaling. It's videos like yours and the knowledge you share that make KZbin and the internet in general a glorious place. Thanks for your response too! Take care

[@electric_fields]

Great video, thank you! What size screwdriver do you recommend for Behringer synth trimpots please? Also, I got the voltages to match, 15v at test points 2 and 3. But when I check them at the alternate test points, the voltages are mismatched. I expected a drop as you describe, but not for them to be unequal. Could this be a failed component? Or another trimpot somewhere needing to be adjusted?

[@tukler2]

A small Phillips screwdriver will work and even a small flat head one will do the job. How much do they differ? It could be a component that’s out of spec. Or it could be just slightly off, but still in spec. Does it still calibrate OK? In a perfect world they would be perfectly matched, but this is analogue technology so they can be slightly off an still calibrate OK.

[@electric_fields]

@@tukler2 thanks for your reply, just came back to this. At the alternate test points I get +14.96v and -14.70v . Unfortunately I can't get down to 1mV level with my multimeter, but by comparison I have +15.01v and -15.00v at TP2 and TP3 respectively. The tuning seems to have calibrated fairly well, though I needed to adjust the offset for both oscillators first. There is some noticeable, almost stepped pitch drift from oscillator 1 when it's left to drone, though it seems to snap back in tune each time. I got a static shock calibrating the rails the first time which is what made me think I may have shorted a component.

[@tukler2]

@@electric_fields I'd leave the way it is if it's playable. -14.70 is a little bit off. It's a bit of work to troubleshoot. But you could try trace the culprit by disconnecting things and check if some components are too hot.

[@losnevels37]

Could this operate without the keys? I would love a module version that can save presets...

[@tukler2]

Yes, is the short answer.

[@lorybari]

Hallo maybe is It possibile ti extract the second line from the effect section? Since the effect Is stereo.....

[@tukler2]

I haven't looked in to it, so I don't really know. I don't have any schematics, there might be just an mono DAC. But it would be nice to have the effects in stereo.

[@martinneal5240]

Thanks for the video....but I dont really understand. You say there is "no need to remove the cover because they are accessible from the top holes"....but then you pull it apart? Can this adjustment be made from the front..and if so how do we do it?

[@tukler2]

You don't need to open up the synth to do the standard pitch calibration and scaling. But I wanted to check that the interna voltages was correct (and I did adjust the - 15 volt). In my case it would have calibrate just fine without opening up the synth, since it wasn't far off. It's OK to start with the pitch and scaling, then if you struggle to get it right you can open it up and check/adjust the voltages and then redo the pitch and scaling.

[@martinneal5240]

@@tukler2 Thank you ...the video and this reply was a big help to me. I find it amazing that such a crucial part of the Arp process is not mentioned up front ...even paid tutorials on it have NOTHING to say. I'ts mind blowing.

[@antonio1984for]

Do you have Barp schenatics?

[@tukler2]

No, and I haven't heard of anyone who has it either. 😐

[@EmperorKonstantine01]

Hello, Thankyou for the trouble shoot video, I have another problem and this may be unrelated to your video but becoming a somewhat common on the Behringer Odyssey, The LED lights on the sliders, one of the group colors on mine has faded and gone dead, all the Seven White ones simultaneusly have died. I check all th\ose LEDS by swapping them out with the other colors and they seem to be working fine but not on those sliders. I have turned up the brightness to full but still no life on the white set. Has this problem ever occured on yours or anyone else's Odyssey ? what could be the root casue of the problem ? something gone dead maybe ?

[@tukler2]

I've not seen this problem before. If all the white LEDs all faded and gone dead my wild guess would be that they been driven too hard. Is the voltage OK? And how high is the current? Is there a resistor that limits the current? By just replacing the LEDs might cause the new ones to die quickly. But that's my wild guess and where I'd start troubleshooting.

[@EmperorKonstantine01]

@@tukler2 Voltage Seems Good at 9.1V input, the symth CV calibration is at steady -5,0,+5,+8V. For now seven of the white multi-color ones are out, Im looking for loose connections or faulty components, when it was dyiing out it was slowly flickering on and off and going dimmer then the others. Im still testing voltage vantage points to see if any of these are higher then the others. The Behringer PCB is not of good quality, very flimsy witha ,Lot of Factory Flux residue and finger marks. I tooked the whole thing apart for further inspections, somehow th 7 LED's are tied to each other. Im Giving it a break now and will have to continue tommorow.

[@sandorkis8813]

Hi! My BArp Vco2 is getting out of tune by itself. Do you think the problem can be an uncalibrated power supply? Osc ranges and tunes are fairly ok, I checked.

[@tukler2]

Sándor Kis I’d check the voltages first, weird things can happen if they’re off. But it could be some other fault behind the problem, especially since the vco1 seems to be fine. The odyssey is usually very stable compared to other analog synths.

[@sandorkis8813]

@@tukler2 alright, thanks! I'll check the power supply. It's obviously the second osc, and it's kinda ramp changing also, in tiny but audible steps.

[@8thedx]

Is there similar guide for the Korg Odyssey module?

[@tukler2]

I have not found any, I don't have the Korg or the service manual. But there should be a simular process of calibrating the power supply. There's a good teardown video here: kzbin.info/www/bejne/aqGXf4ifgNyrptE

[@8thedx]

@@tukler2 Thank you for this video and the link!