Here is the 200W MOSFET amplifier powered based on four piece of IRFP250N, they are very cheap and easy to find in the electronic market in your area. The circuit has been assembled and tested with very good performance.
This 200W MOSFET amplifier circuit designed for single or mono audio channel application. You should build two similar circuits for stereo audio application. Build one first for performance testing to ensure that this circuit really wongking well with great audio performance.
The power supply used for this circuit is a symmetrical / dual polarity type. You need 4 amperes minimum of transformer with +/- 45V output. For stereo application, use about 8 amperes, although the 5A transformer is good enough 😀 . You may use the power supply circuit design on this post: 200W Power Amplifier using Transistor
200W MOSFET Amplifier PCB Layout Design
Bottom / Chopper PCB Design
Top PCB Design / Component Placement