Design News Gadget Freak has a new how to on making an audio amplifier muting circuit – “Ever turned on your car stereo and BOOM! the woofers unexpectedly jumped out for one filling-loosening bass note? Just great, you’ve just been diagnosed with turn-on thump — either due to an amp that never had a muting circuit or one that’s failed open circuit. Either way, OUCH! To fix this problem, Gary built a circuit that connects externally to any car audio amplifier and keeps his speakers completely disconnected from his amplifier until it’s been completely powered up. Plus, it also works with a mis-matched set of amplifiers.” – Link.