Pocket Operator 400 to Eurorack mod

Ordered a PO 400 the day it launched and have had some fun with it. Already finding myself wanting to hack it somehow. I feel like it needs integration with a larger system. Being new to modular, maybe I’m not clever enough to get the full sound out of the PO. Being an engineer, my solution is to build something to extend it. I’m pulling my PO 400 modules into a Eurorack system in order to combine it with other DIY modules. Here’s my first step (with documentation).


Woah! This is super rad. Nice work on the faceplates. Do you mind if I share your github link with the users on my op-z group? There are a few people who are using the PO modular who would be very interested in seeing your work!!

That is just genius.


Yes! Is this an open group? I’d love to hear feedback and see what others are doing with PO gear.

I’ll private message you!

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@kyle This might seem like a stupid question but which pins of the bus terminal did you connect to? I just fried a module…

Screen Shot 2020-07-11 at 11.10.14 AM
Oh no! That really sucks, hope it was only one module. I connected to the -12v, GND, and 12v lines on my Make Noise Skiff. I’ve had no problems with the modules and they play well with other non-PO 400 modules in my setup. There is a possibility that TE has redesigned the power requirements for the modules. I know they did an update on the PSU for their device. Eurorack power supplies come in all shapes and sizes too. I can’t think of a reason why some would cause problems, but it would have probably been a good idea to put in a fuse on the bus input wiring. The PO-400 has a simple PSU that can’t crank out a lot of amps. I’d imagine the teenage engineers didn’t need to be as obsessive about power supply safety on the modules as someone building a module for general use.

Thanks for letting me know. I’m adding a warning to the top of the repo.

Which module was it, I might have one not in use if you want to put it back into your original PO-400.

At this point, I WOULD NOT recommend adding more modules to your rack without some sort of power filtering circuitry on the breakout bus. It seems I’ve been lucky not having problems without it.

How many modules are in your rack that had the issue? Any specific power hungry/dirty modules you can think of? I’m thinking it fried at startup because the power fluctuated a lot. I think there are some specific tools to delay startup of modules to help with this.

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Thanks for the reply, it was the sine. For power I was using the tip top audio uzeus with only the single TE module. Only one of the orange capacitors on the left hand side blew so it might be possible to fix it.