Official comment
You're not going to like this... but the XDJ-RR requires a unique DC adapter; it's a 12V / 3A 5.0x3.3mm barrel with pin, tip positive. That connector type is known as an HG7, but don't just buy any HG7-rated DC supply as most of those are 15-26V for laptops.
You can buy a replacement from our parts supplier; here's the official US one, and here's a knock-off one in the UK.