Just as a note as it doesn’t seem to be anywhere else on the internet (and was quite tricky to find out): the power connector for the Korg Kaoss Pad 3 is JEITA RC-5320A JSBP4 standard:
Outer diameter is 5.5mm
Inner diameter is 3.3mm
Centre diameter pin is 1mm
Plug I used was a Lumberg 1636 04
It’s also nowhere as greedy as the PSU is specified, it’ll boot up with as little as 9V 100mA
This may also be applicable to other Kaoss Pads and other Korg products.
And using alien power supplies may invalidate your warranty etc etc