That ancient Peavey transformer might be hotter (thermally! not
wattagely!) on 50hz than on 60hz, and class AB amps dissipate worst
case power at about 1/3rd max power.... its where the load line runs
right across the hyperbola on the IV curve... and if the voltage in
the club sags when the drink cooler compressor turns on, its a perfect
storm of overheat factors.