OP-1 Field: both power and MIDI over USB-C?

Hey people!

I just recently found out the stunning power of an OP-1 combined with a Polyend Tracker, using the OP-1 for synths, drums and effects, its tape for clock and recording, and the Tracker for sequencing. Since the OP-1 can also charge the Tracker, it makes for a super portable setup as well. For me, this tiny little combo is near perfect.

One drawback is that powering both itself and the Tracker is quite a load on the OP-1, so the battery only lasts for a few hours maximum. So in case I plan on jamming for long stretches of time, what I’m looking for is either:

  • A USB-C splitter so that there’s power going into the OP-1 and power and MIDI coming out all through the same port


  • Some sort of powered USB-C hub that just sits in between the OP-1 and the Tracker, that charges both devices, and that also receives and sends MIDI between the two.

There’s a whole bunch of USB hubs and USB to DIN MIDI things and what have you, but I still didn’t manage to find what I’m looking for. Which surprises me, since so many recent devices rely on USB-C for sending/receiving MIDI, while also needing the same port for charging. Or would any old powered USB hub work?

Anyone here familiar with this kind of problem?

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Hi, i use this
https://a.aliexpress.com/_EwO4hPZ with the op-z and work perfectly


What kind of device do you hook up to the OP-Z this way?

I can understand the OP-Z receiving power from the USB-C end of the splitter, but I don’t think it can send power over the USB-A to the other device you’re connecting? Because that’s the problem in my setup: the Tracker also has just one USB-C port, so it needs both MIDI and power. What I would need is a splitter with USB-C on three ends, one that receives power from the wall and passes it into the OP-1 (no data required), and two that pass MIDI both ways and also charge both devices.

Ideally, it would work like this:

But since most USB-C splitters I come around receive charge from the wall, send it into the device, and at the same time get data but not charge out of the device, maybe a two splitter contraption would work?

In my case I use it to power the OP-Z and through this adapter I connect various midi controllers to it. I’ve also tried connecting a small two-port usb hub to it and it works. it should be clarified that through the usb-c socket of the adapter only power passes while from the usb type A socket both data and power pass through…now i’ve also tested with my Op-z and Op-1 field and what you need i think is possible…


This sounds like the exact solution I’m looking for. Thanks for clarifying, I’ll try this out for sure! :+1:


I’m trying out a similar setup and will let you know in the next few days how it works

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I got a USB-C to USB-C/USB-A splitter, but unfortunately no luck so far. When connecting USB-C from the wall into the splitter, and the splitter into the the OP-1, the OP-1 receives charge. But when I connect USB-A from the splitter out to the Tracker, the Tracker receives no charge, and the OP-1 also stops charging.

The other option looked to be more successful: from the wall to the splitter into the Tracker, and then out of the Tracker to the OP-1, both devices charge. :partying_face: But then there’s no MIDI running either way. It feels like when the splitter passes charge, it won’t also pass MIDI.

I might try a second splitter, so that both devices get their own charge, and one USB channel is reserved just for MIDI.

I’ve tried a cable like the one in the photos above, but no luck on my end either! I wonder if I need to just bite the bullet and use this guy:

Using a different splitter with power coming from the wall into the OP-1, and a USB-C cable running from the OP-1 into the Tracker, still won’t work. HOWEVER! I did manage to get the second idea to work: both devices now have their own splitter that receives power from the wall, and the remaining end of both splitters is used for sending MIDI back and forth over a USB-C cable. Here’s a video in which the OP-1 sends clock to the Tracker, plays music from the tape, and the Tracker simultaneously sequences an OP-1 drum kit.

I do have to admit that this contraption is kind of a balancing act. Powering both devices this way always works, but sometimes MIDI just won’t. I’ve had it happen that just by unplugging/plugging a single cable and rebooting the Tracker, MIDI suddenly sprang to life.

I think your mileage may vary a lot depending on which devices you use for this setup. As an example: receiving charge from the wall to the splitter into the Tracker, the Tracker won’t boot, only when it also receives some charge or signal over USB-C from the OP-1. So the Tracker looks te be very specific about what current it needs, unlike the OP-1, which charges no matter what stupid charger you use.

I’ll try this whole setup over a consecutive period of time to see if at any point either the power or MIDI drops, or to see if in the end it’s still the OP-1 powering the Tracker instead of the wall current.

The fact that the tracker won’t turn on unless you also have a connection to the OP1 makes me think that you’re still having battery drain from the OP1. Also, you’re now plugging two devices into the wall which kind of defeats the purpose of a mobile set up!

After a day of usage I’m glad to conclude the OP-1 is still fully charged.

You’re probably right, but since the OP-1 is being powered at the same time, it doesn’t lose its charge.

I preferred this to be a one plug configuration for sure, but the main intent was for this setup to be mains powered instead being powered solely by the OP-1. Truly mobile is also possible: just connect the OP-1 to the Tracker with one USB-C cable and you’re done. But after some three hours, the OP-1’s battery will be dead.

By the way, I also managed to get this to work :arrow_down:

But I could clearly hear the Tracker buzzing and the screen flickering, so I didn’t really trust this setup.

I wonder if a 2 port USB power bank would let you send charge to both the OP and the polyend with the two splitter set up method?

Could also go in a different direction to take polyend USB midi out of the equation and use the TRS out:

My power bank does have two output ports, but powering both the OP-1 and the Tracker and delivering MIDI didn’t work.

However, this suddenly did work, both power and MIDI:

As an example of how unpredictable this whole setup is: when I unplug the splitter from the OP-1 and directly plug in the white cable, MIDI stops working. :laughing:

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I need to retrace my steps a little here. Powering both devices from one single power bank does in fact work, even quite reliably so:

Unfortunately I need to emphasize that all of this is no guarantee that it will also work for others. For instance, the two spitters are same shop, same brand, same specs. But when I swap them, the whole thing just won’t work anymore.

That’s bizarre.
But am watching this thread as I am curious of the device combination…