My most recent and best sounding cord for my amps have been AudioQuest Hurricane… exceptional power cords. If you look around the forum, they have been discovered by many. Clearly one of the design points is the tight fitting connectors. I have to hold my amps to prevent them from sliding when inserting or pulling out. I have more than one and I have no question that this was done on purpose.
If you wish a better cord, I have heard Dragon’s are great, or lower levels of the Storm series.