Basic check. Did u terbalik the +12 and ground?
It's also possible the amp itself got issue

My guess is the 3205 MOSFET touching the bare heatsink

Try claim warranty? If no warranty just send for repairs.
The MOSFET is rm5 so shouldn't be very expensive to repair.

This post has been edited by fireballs: Jun 7 2021, 11:14 PM