No guarantees on quality but mine worked fine for two nights of practice so far.
I bought this supply:
I cut the power plug off and put this male IEC connector on it:
Then I cut the plug and some wire off of an old wall wart that used the same size DC barrel plug. I don’t recommend this method unless you know how to solder and how to work a multimeter to verify the output voltage and polarity. But if you’ve got that then this is way cheaper that the COIKS and doesn’t include any of the extra features that I’m not using.