The unit has an over temperature and shutdown protection. If the unit is continuously used for a long period and overheats, the unit will shut down. Leave the unit ‘OFF’ for 10 minutes to cool down, then turn the unit on to continue listening.
If the problem persists, then the unit is being over driven. Reduce the volume level, and ensure the unit is in an open ventilated area to resolve the problem.
Use of two pairs of speakers which are less than 8 Ohms can cause overloading and is not recommended.