Whew, so far my Summits and other A/V gear seem OK! Kitchen phone got fried, and Master BR Tivo won't power up. Hopefully no other major damage.
It’s always worrisome when these things happen, and I’m glad your main A/V is OK.
I agree that maximum protection and effectiveness occurs when all devices are on common grounding and all hanging off a single conditioner.
There are still many challenges, everything is so interconnected these days.
Seven pieces of A/V are networked, but most network linkups are opto-isolated, so hopefully that's not a problem.
then the Satellite TV DVR's have cables going into them coming from that little lighting rod, er antenna, on the roof. Even when those are well grounded, that's the one that makes me nervous the most.
But then, there automation systems, often with Serial connections that establish new ground paths, audio connection from PC’s, etc. All of these need to be examined.
This is when tools like Jensen transformers come in really handy. I’ve had to resort to them in the past to kill hum, and to break external grounding paths.
Luckily right now, my uber-complex system is hum free, and does not need any transformers to get there as it’s almost all balanced analog connections or Digital (HDMI, DenonLink, toslink).