Lightning

I am also in Florida , the central part . I have gotten used to leaving everything unplugged until I want to use it . The tubed amp and CDP only take 30-45 minutes to warm up. But the SS phono stage takes @ 7 hours and that is a real PITA ! I will be starting a new thread looking for recs for a decent , warm sounding tubed phono stage to replace it .
It is the price that I pay for living in paradise ! I really hate the winters up north !
And I agree with the replacement value coverage suggestion.

Good Luck

Short of installing lightning arrestor system to keep lightning from hitting your house in the first place, nothing will protect your electronics from a direct lightning hit to your house or the service entrance; however, a few basic precautions will go a long way in minimizing damage from a nearby hit.

First is to make sure that all grounds are tied to one place at the service entrance and it's a good ground with at least two ground-rods pounded deep in the ground. Cable and satellite TV installers are notorious for sticking a ground rod in wherever it's convenient with no bonding whatsoever to the house's service-entrance ground. When there are two grounds, one at each end of the house with no direct common bonding, a lightning-strike occurring nearby can crate a high-voltage unequal-potential between the two separate grounds. Guess how the potential balances itself out? That's right. Through the lead-in coax and through your TV and anything else that is connected and grounded or tied to the neutral leg - which is everything that's plugged in! So check and fix your house ground first and foremost.

Now, like Swanny said, go out and buy or rent through your electric-service provider a whole-house surge-suppressor. Don't worry it would hurt the sound of your system and it's worth every penny.

Also remember that MOVs, which actually do the surge suppression in most strips and power conditions, wear out with age. Depending on the number and size of surges that are absorbed by it, figure on replacing the MOVs in the device every four- to eight-years. MOVs are quite cheap but require some soldering to install. You may be quite surprised open your power conditioner and see a blackened and burnt MOV or two, but it not uncommon, especially here in Florida.

> My theory is that the huge moving charge induced a voltage in the amp's mains primary.

First start with basic concepts even introduced in elementary school science. Lightning seeks earth ground. A path for a 20,000 amp electric surge is via a wooden church steeple destructively to earth. Wood is not a good conductor. So 20,000 amps creates a high voltage. 20,000 amps times a high voltage is high energy. Church steeple damaged.

Franklin installed a lightning rod. Now 20,000 amps is via a wire to an earthing electrode. High current creates near zero voltage. 20,000 amps times a near zero voltage is near zero energy. Nothing damaged.

Lightning seeks earth ground. A lightning strike to utility wires far down the street is a direct strike, incoming to every household appliance, destructively to earth. Appliances are not a good conductor. So lightning creates a high voltage. Lightning current times a high voltage is high energy. Appliances damaged.

Second, for over 100 years, facilities that cannot have damage installed superior earthing connected low impedance (ie 'less than 10 feet') via one 'whole house' protector. Then high current creates near zero voltage. 20,000 amps times a near zero voltage is near zero energy. No appliance is damaged.

In your case, everything that was damaged had both an incoming and an outgoing path to earth. If both current paths do not exist, then no damage. Often damage is on the outgoing path. For example, the amp. Incoming on AC mains. Outgoing on the right channel to earth via a speaker wire touching the floor. Surge passes through everything in that path; simultaneously. But only damaged is a part(s) inside the amp.

Third, one shot protectors are a scam. Either earth a surge BEFORE it can enter a building. Or a surge will go hunting for earth destructively via appliances. Earth ground electrode is your protection. Each incoming wire must connect low impedance (ie 'less than 10 feet') to that single point earth ground either via a hardwire or a protector. For reasons even demonstrated by Franklin and his lightning rod.

Nothing new. Protection has been done this way for over 100 years. 'Whole house' protectors come from other and more responsible companies including GE, Siemens, Ditek, ABB, Polyphaser, Square D, Syscom, Leviton, Delta. Siemens. and Intermatic. To name but a few. A Cutler-Hammer solution sold in Lowes and Home Depot for less than $50. A least expensive solution has also been the best. Proven by over 100 years of experience and science. So that a protector remains undamaged even after a direct lightning strike. As explained in four topmost paragraphs.

Respectfully, it is no secret that lightning wants to reach earth ground by the path of least resistance, but that is a simplistic view as I believe there are other things going on as well.

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/lightning2.html

Even without instrumentation, I can vouch there must have been a great magnetic field moving through my house that day as every one of my TV's had their CRT's magnetized. Not destroyed, magnetized. In the case of my unplugged amplifier, I think the moving magnetic field of the tremendous bolt induced a current into the coils of the mains transformer. The damage cascaded from there.
Preamp was undamaged, as was the tape deck and CD player. Only the component with the biggest transformer was affected.

> I can vouch there must have been a great magnetic field moving
> through my house that day as every one of my TV's had their CRT's
> magnetized.

A tiny field creates that distortion. Nuclear submarines suffer a similar effect by simply traversing oceans. A tiny degaussing coil of similar strength automatically undoes residual fields in that CRT.

Meanwhile, lightning struck a lightning rod. Maybe 20,000 amps flowed from that rod to earth. Some four feet away from that wire and 20,000 amps was an IBM PC. It did not even blink. That field is much larger than anything you saw in your house. It did not affect an IBM PC, nearby digital watches, mobile phones, digital clocks, or anything else. The most sensitive transistors connect to a radio antenna. To amplify tiny radio fields. Even those were not harmed. Because a field created by 20,000 amps is made irrelevant by protection already inside all electronics.

Damage means a current had both an incoming and an outgoing path. Only then can internal protection be overwhelmed.

Was the transformer damaged? Or some other internal part? Valid conclusions do not exist without knowing specifically what internal part failed. And every electrically conductive material it was in contact with. Even concrete is an electrical conductor.

We did this stuff. If damage occurred, we had to find the human created mistake that permitted an incoming and outgoing current. That current always explained the damage. But many items you may have assumed are insulators (ie floor tile) are actually electrical conductors.