Changing the DC input jack of an old Deluxe Electric Mistress

[Vax]

Hi all,

I wanted an end-all solution to powering my pedals, so I opted for a Dunlop DC brick. I have a Deluxe Electric Mistress that's really old, so the jack is of a different size than the 18V power cable that comes with the DC brick.

Has anyone changed the size of the DC input jack before? Is it simple enough to DIY? If not, any modders I can approach?

Thanks for reading.