I am still struggling to get it to work with wall power.
which power supplies are you all using?


I also haven’t found a working power supply. I’ve tried several that meet the specs.


…you would be better of writing to Santa…( not the boutique version, plain one )


Filter: same behavior here


Make sure it follows the music world standards, which are the opposite of the usual wiring: center negative, barrel positive.


yes, I checked the polarity, but no luck … maybe the plug has to be exactly a 4.75/1.7mm plug? closest I have is a 4.0/1.7 …


My po-400 was delivered with 2 sequencers and no mixer module. Odd thing is there was the box for a mixer, but it was a sequencer module inside instead. I am losing hope that support will ever write me back. Been a few days now, but keep hearing other people complain about not hearing back from them on various things for weeks.


Having power supply trouble. Bought one on Amazon that seems to fit the bill–but i get no lights when i flip the switch. Don’t have the guts to try much further. Is there a specific supply people have succesfully used?

One other thing. Maybe it’s just me, but this “Pocket Operator” cannot be triggered/synced with a PO. Voltage must just be too low. Wish it had a switch for that or something. Does it?


I dont know if this your first experince with TE support. It is a huge problem and it is well known. If you add to that that this was sold as assemble it yourself, makes the issue nore complicated. Personally i would never and have never bought from their shop. I got an op1 when i was in germany 2016 through a shop. German shops are to my knowledge the best. I had to returned the op 1 three times because it was faulty. Knobs would freeze. The fourth one worked. You get full support from the shop…


Yeah PO sync voltage is too low, PO modular clock output needs to be attenuated to sync PO to modular, PO sync needs to be boosted to clock PO modular, there is no switch.


I made a proper mains adapter now, if any UK users want to buy one I can make you one for £20, works great, no overheating issues and correct size plug.


could you share your findings/build/parts etc of your solution? i am interested and maybe helps other users too. thanks!


Sure, you need a regulated 12v 1A DC power supply, then a DC barrel plug with 4.75mm outside diameter and 1.75mm inside diameter, then solder the connector to the cable from the power supply making sure to connect negative wire to centre pole of connector, and positive wire to outer pole of connector.

Hope that helps!

4mm outside 1.7mm inside dimensions for the plug will be unsuitable as it will be too loose for a reliable connection, the 4.75mm is actually quite hard to find, but luckily I had some in my parts drawers.


I was able to adapt a 4x1.7mm plug by wrapping some conductive copper tape around the barrel until it fit snugly. Dirty, but it works!

Also, the proper 12v power supply (not one I cobbled together) is able to power the unit with significantly less whine from the PSU, so it’s probably still under-volted, but the bottom transducer is no longer uncomfortably hot-to-the-touch and the whine not nearly as abrasive.

Not ideal, but I’d consider it “usable” as such.

I was able to reproduce the slow filter, too.


That is a clever little hack, I’ll remember that one for the future as I often seem to never have the right size power plug, thanks!

FWIW with 12v 1amp I’m not getting any whine at all.


Thank you darenager!
Ok, so I guess it all comes down to exactly the right plug. Like you said, they are actually quite hard to get.


You’re welcome, this is the type I have:


So I’m supposed to be getting mine within the next day.

Should I even bother putting it together?

I was really jazzed to get into modular synths at a relatively cheaper cost but at this point I’m not sure I wanna deal with the issues the 400 series has.

Can anyone recommend a comparable modular set under 1k?


there are many options for 1k. volva modular + 0-Coast + Neutron , all together would cost the price you mention. There is the Phenol for 1k i think…


ps. actually the phenol has come down in price…750…