1. Start-up delay DC protection, anti-shock when power off; 2. 7812 is used for voltage stabilization, and the power supply range allows AC12V to AC24V; 3. The pull-in time is about 2 seconds; 4. The use power is up to 200 watts, which can be increased to 400 watts when used in mono parallel connection; 5. The circuit is simple and reliable. It is very easy to make and free of debugging; The product is suitable for OCL or OTL output power amplifier circuit, not suitable for BTL! Use independent windings to supply power to the protection circuit, so that the power loop can be closed, otherwise the speaker ground and signal ground are mixed together, which will easily produce interference and hum. (The common use of the front-level power supply and the protection circuit can easily produce humming). Color: As Shown Material: Plastic+Metal Package Contents: 1 x UPC1237 speaker protection board