Option to Set TRS-MIDI to Type A or B

(First time? See Writing a good feature request)

Allow Polyend Tracker and Play to connect midi to any device with TRS-MIDI using a simple 3.5mm stereo cable.

What is the problem?

TRS-Midi input and output on Tracker and Play are of the type B variant. I have other synths and grooveboxes with type A TRS-Midi (type A was selected as industry standard). Therefore I cannot use a regular 3.5mm stereo cable to connect between Polyened devices type B TRS-Midi to other devices with type A TRS-Midi.

What do you want to achieve?

An option in Settings to set TRS-Midi to type A or type B. Ideally Midi in and out can be set independently, otherwise setting both Midi in and out together is OK too.

Are there any workarounds?

(1) Custom-made 3.5mm stereo cable where left and right channels are swapped at one end. (2) Type B TRS to MIDI adapter >>> Midi cable >>> Type A TRS to Midi adapter

Any links to related discussions?

Not that I know of

Any references to other products?

There is a list of Type A + Type B compatible devices over at https://minimidi.world/
Most notably the Elektron Model:Cycles. Where polarity can be switched through a setting in the config.


I personally don’t know if this can be fixed properly on a software level. So i’ll send this on to Polyend :laughing:

I have solved this by using TRS-A to TRS-B Minijack Adapters like these:

Relatively inexpensive without adding any bulk, unlike the DIN Adapters.

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@xjazzdummy Welcome to Backstage!

Any references to other products?

This section is to mention other products that have this feature. Is there any product that can switch MIDI type?

I believe this is a hardware setup that can’t be changed. As @Sandroid says, the simple alternative is to use an adapter.

I’ve updated that part with a reference to https://minimidi.world/ that has a good list of devices that are capable of both.

For the most part it’s either a switch though or there is already hardware inside that can auto-switch the polarity based on a config setting or even differently. Hence why i believe this may not be possible on the Polyend Devices.

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Wow, I didn’t even know there are devices that change switch polarity between type A and B. That’s exactly what I had in mind. As Midi is not handling analog electrical signals, I hope this is something that can be changed in software. Otherwise I’d have to find someone to custom make some cables or adapters.

Let’s see what Polyend can tell us, but i’ve read a couple times that solving this in software can be rather difficult.

But in the meantime… is there a reason why something like this won’t work for you?

They work for both ways, since all they do is switch polarity. So you can use it for A → B or B → A.
Also worst case, soldering a custom cable wouldn’t be too hard either, if you just don’t want a connections in between, since all you’d have to do is solder the one end differently:

@xjazzdummy for example, when I got the Play, I realized that it had a different MIDI type than my little Dreadbox Nymphes synth. I spent a few euros in one adapter, and that was it. Solved. These adapters are cheap and pretty common because it is quite easy to end up with devices using different MIDI types. Luckily there are only two types. :slight_smile:

This does work, just that I’m located in Asia and buying the adapters from Amazon or Retrokits and then shipping to Asia is not economical. Plus of course being able to use a single cable would be simpler. If this can’t be fixed in software, I’ll probably find someone to custom make 3.5mm TRS cables with tip and ring swapped at one end (I’m bad at soldering).

It is probably too late for the tracker because it’s a hardware issue, but I have designed a rectifier circuit for TRS MIDI so you can use A or B cables on your device and it does not care. it is used on various Michigan Synth Works devices and modules, but is free for anyone to use. the BOM cost is just 2x BAT54 double diodes.

I suppose i should put it on my github! (edit, here it is) GitHub - jakplugg/PSI_MIDI: Either way 3.5mm TRS MIDI for your device.

The funny thing is i have been trying to use MIDI clock with my tracker and it was not doing anything. I’m so used to 3.5mm MIDI just working that I completely forgot about it until i saw this post.


Oh hey @jakplugg welcome! Awesome to see you here! Love your Modular Stuff! :heart:

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Try this for swapping types
Simple Fix midi trs A/B to ANY synth! - YouTube

@john.alchemy.beats Thanks! Yes, I thought of this too. I’m going to buy the adapters coming Sat while waiting to this request goes through.

@xjazzdummy Thanks for your contribution, unfortunately this cannot be fixed on software level so we have to reject it as hardware limitation.

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