Review on MUSYSIC 4000W Hybrid Power Amplifier/Pre-Amplifier/Receiver with Bluetooth, AM/FM Tuner, USB/SD Slot, MP3 Input, and iPod Compatibility - MU-H4000BT by Reginald Hamilton

After ten minutes of amplification at 5/8 volume the sound quality began to degrade and before I could reach the amp to turn it off it went into protect mode. Apparently the exits burned out. I'm an electronics engineer. I need to replace the output transistors or IC. and circuits damaged by overload. This.; Resistors, capacitors and preamp transistors, most likely damaged as well. At least the protection mode worked, otherwise it would have completely destroyed the included logic circuits of the amplifier. The problem is that this should never have happened. I use it on four 8 ohm speakers with 500 watts RMS. This was to be the cheapest design, requiring four thousand watts of power output. The sound quality was good while it lasted ten minutes, but then when I heard the distortion start it exploded. This amp is rubbish and I want a full refund.