Or a dim-bulb tester. That gives some of the benefits of a variac plus protects from shorts doing real damage, and is cheap/easy to make!
mother-in-lawLend it to a distant acquaintance looking to dip their toe into hifi?
There is a huge German naval gun in northern Norway that the Norwegians wanted to test fire after the war. They were worried that it might be booby trapped so they tied 200m of rope to the trigger and retired a safe distance. Worked fine for them