The Canary may have the (+) and (-) sides of the A/C input reversed?
To check you would have to make a cheater box, to be able to reverse the A/C line hot and cold. But it might be worth checking out.
Short extension cord, a wall outlet box, plastic is best, a wall A/C receptical. cut end off extension, wire receptical in box reversed from why it is supposed to be with hot on wrong side. (ground is normal) IF it quiets hum then your Canary is probably wire hot on wrong leg. And just fix it.
To check you would have to make a cheater box, to be able to reverse the A/C line hot and cold. But it might be worth checking out.
Short extension cord, a wall outlet box, plastic is best, a wall A/C receptical. cut end off extension, wire receptical in box reversed from why it is supposed to be with hot on wrong side. (ground is normal) IF it quiets hum then your Canary is probably wire hot on wrong leg. And just fix it.

