Why not get one from the retailer that sold you your Modx M8?

The 'official' adapter is a Yamaha 'PA-300C (Output: DC 16 V, 2.4 A)' as shown on page 45 of the Quick Guide and uses a 120 VAC source. Both Canada and the USA are compatible in that regard.

CAVEAT: years ago there was a recall of that model although at the time it wasn't sold at retail but was built-in to certain instrument models.

But you should make sure you buy it from a reputable source. If you don't have a retailer near you there are good sources on Amazon.

Using the wrong power source can ruin your instrument so the adapter  is NOT the place to try to save a few bucks.