That’s a pretty big place, “outside USA”, could you be more specific? Even within Europe, there are many types of connectors at the mains (input) side.
This probably means:
Output is AC (not DC)
Voltage is 18 volts X 2, so probably an 18-0-18V transformer
Current rating in 1.4 amperes
… so it’s basically just a transformer, with a particular connector.
The one in your link is only 600mA, so can’t deliver the required current.
I found this on The Thomann UK website, which appears to be an exact replacement: https://www.thomann.de/gb/yamaha_pa_30.htm
That has a standard 2-pin mains plug (a “shaver” connector), so, as there’s no requirement for an earth (“ground”) connection, you could use a simple shaver adapter of the type sold in every airport to connect it to the local main supply. Thomann also supply a Euro-UK adapter which is a better, more permanent solution if you’re intending to use it in the UK or Ireland.