If using 220 ohm resistors they needn't be anything like 5 watts - even
assuming an 'HT' rail of 12 volts and a dead short. Standard 0.6w metal
oxide types will be fine.

The "HT" rail is quite likely to be in excess of 12V, especially if the
power output is reasonable (i.e. much in excess of 10W rms/channel).

Christian.