I know basically nothing with about audio engineering and need some help. I just recently bought a Yamaha emx5 powered mixer. What is the best way to protect it from a power surge? Do I need a power conditioner? Also can I run a extension cord then plug in the power conditioner? Any help would be appreciated!!!! Thanks!
Power conditioners serve more than just a surge suppression role, but for a small all included system like this you probably don't need to worry much. It might be worth a basic surge protector to protect it if you want, but unless you are having problems with noise, you probably don't need a power conditioner on such a small setup. Power conditioners are more important when you have higher power needs with racks of gear that need stable power across devices to prevent variations in voltage and ground levels, which really isn't applicable here.
You could hit ground differential problems on different circuits, but simply plugging in to the same circuit should fix that for small setups.