25-04-2018, 01:11 PM
Both channels should be much the same. Hum is usually caused by C5, but while it's there, it'll be worth changing all the electrolytics on the amp boards. The bootstrap cap (C10) sits next to those 560R power resistors cooking gently. Check for dry joints on those while the board is out. You'll get heat sink compound everywhere when working on these - enjoy 
