Hifisonix Speaker Protection Board

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 for $12.95 plus $14 shipping, total $26.95 or two boards for $20 plus $14 shiping.

Contact me at bonsai(at)hifisonix.com if you want to purchase speaker Protection boards

Here is a short presentation on the use of mosfets for speaker switching in amplifiers