Little Things: Triggering Multiple Amplifiers From A Single 12V Trigger - HomeTheaterHifi.com
Amazon.com: Digital Audio Trigger Device with 12V Outputs - BobWire DAT1 Ads a 12 Volt Trigger Output to TVs, Streamers & DACs, auto Power on amplifiers or TV Lifts. Compatible with Sonos
Audio Signal or 12V Trigger socket UK EU Mains HIFI Socket automatic ON/OFF 230V | eBay
Audio Signal activated 12V trigger box automatic ON/OFF for active speakers subs | eBay