Overheating of my SUBWOOFER (booster , no speak attached)5CORE HT-2118

My subwoofer(booster) 5core HT-2118, always heating from the back where i connect the output (surroundings or the small speakers)

Due to this heating from the woofer, it has cause damage to the small speakers

I went buy another small speaker

And it has spoiled again

Please any help

U can reach me