Hifisonix Speaker Protection Board
This simple, low cost speaker protection board uses the ubiquitous UPC1237 from Unisonic, a Taiwan based semiconductor manufacturer. The circuit will work from 25V through to 75V and uses mosfets to switch the speaker load rather than relays which are problematic and unreliable. A current overload input is also provided, allowing builders to arrange to sense an amplifier output short circuit and rapidly disconnect the amplifier output.
Here is the BOM
You can buy a PCB by clicking on the button below. Please allow 5-7 working days for delivery.
Here is a short presentation on the use of mosfets for speaker switching in amplifiers