Description: The speaker protection board has two main functions: to protect the audio amplifier and the loudspeakers during start-up sequence when the amplifier output might exhibit DC voltage, and to protect the loudspeakers in the unlikely event of an amplifier power stage failure, where DC component would damage the speaker voice coil. The core of the speaker protection board is the UPC1237 dedicated circuit. Features: This board uses 7812 as a voltage regulator and has a wide supply voltage in range of AC 12V to AC24V. UPC1237 circuit as core has power-on delay function, DC protection and power outrage damage protection function. These two relays are original and of high current so you do not have to worry about contact ignition and oxidation. Compact size, board size is only 6.9x5.7cm, and the c ircuit is reliable and simple to welded, no need to debug. This version can be use to control 500W amplifier, each channel using a high grade relay control. Convenient placed large type terminal block connectors for signal input and signal output. DC monitoring and real-time protection for speaker supports disconnecting speaker instantly when power off. Specifications: Power: AC 12-24V Power-on Delay: Support DC Protection: Support Outage Damage Protection: Support PCB Size: 6.9 x 5.7cm / 2.71 x 2.24" Package Includes: 1 Set x Speaker Protection Board(Disassembled Parts) Note: This kit requires electronic knowledge and ability, please make sure you know how to assemble and use it. Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering. .