After buying some Teenage Engineering Pocket Operators and an audio mixer I needed a way to sync all POs and also route audio from each device separately. Initially I found the Sync Splitter made by p0k3t0 but unfortunately it's unavailable for the foreseeable future.

So I decided to make my own with the most basic materials I can get. This approach is pretty rudimentary, but it does it's job.

A more skilled individual can use solder breadboard, but the principles remain the same.

Supplies

After some research I settled on some standard items:

a breadboard
a mini size can sync 3 devices
a half size can sync 6 devices
PJ-307audio female sockets, this type can fit a standard breadboard
5pcs for mini size
8pcs for half size
breadboard jumper wires (I got a pack with different lengths)
2pcs of 3.5mm audio cables for each Pocket Operator, one for sync and one for sending audio to the audio mixer
A good tweezer is recommended, it will really help when adding the wires

Step 1: Starting Tips

If you use the half size breadboard you can remove the power rails, you don't need them and it interferes with the audio jacks.
Not really necessary but I highly recommend to cut the little plastic feet from the sides of every audio socket to make it sit flush with the breadboard.
Please be careful not to cut yourself. Also I really recommend when handling these audio sockets to grab them by top/bottom, not the sides, it can easily flip and poke your fingers with the pins. Learned that lesson after stabbing by fingers a couple of times. 😅

Step 2: Add Audio Sockets and Wires

You can follow the image as a guide, the wires will overlap in some cases so some bending is necessary, but here are some general steps:

Plug the audio sockets to the breadboard, with the middle pin (ground) on the first row, such way that it leaves two rows free for wires inside (the back of the socket sits a little over a row)
You will need to connect the ground pins (blue) of all the sockets
Connect the right channel (red) of the master in and master out sockets
Then bridge the left and right pins of the master out socket to send audio on both channels
Connect the left channel (green) of master in socket and all sync sockets

Step 3: Test It

This is the my final result I made, the jumper wires are a bit janky and are not following the color scheme above, but it does it's job.

Here are the necessary steps for testing it:

Connect the output of the master Pocket Operator to the "master in" socket
Set it to SY1 by pressing "Record" and "BPM" in the case of Pocket Operator PO-33 or PO-133 (check manual for your version of PO)
Connect the "master out" to a channel of your audio mixer
Connect a "sync out" to the input of each secondary Pocket Operator
Set each one to SY2
Connect the output of each secondary Pocket Operator to a channel of your audio mixer