Official comment
Yes, it's universal voltage, and unfortunately, yes, it is notoriously difficult to find an off-the-shelf replacement.
For the record, it's a 5.0x3.3mm with centre pin, tip positive (apparently known as an HG7). The majority of those connector types seem to be for laptops and are rated 17V-26V, which is more than the 12V required by the various Pioneer DJ units for which this adapter is compatible.
The only one I know of is at our parts supplier, but it's really expensive. I'd almost be more inclined to buy two different adapters and chop the ends off myself.