I ve just purchased a pair of musical fidelity xa50 mono bloc power amps from a shop of e-bay, ive got the little fellas driveing the bottom end of my b&w's cm2's with my xa1 (mf) looking after the tweeters, it sounds great but for some reason one of the mono blocs gets a tad hot while its partner doesnt seem to get that hot, there is a noticeable difference in heat between the two, should this be a worry if there working fine or should i get in touch with the shop? The last thing i want is for things to go pop, prevention rather than cure? ps, ive checked connections, leads, etc.