How to protect my amp without changing the sound?

No, I could not detect any difference with arrester. Furman with its tight, strong, non-sacrificial under/overvoltage protection and build in circuit breaker is probably enough but double protection sounds better. In addition I've already lost garage door opener (Chamberlain) due to the voltage spike. Chamberlain service lady explained to me, that during winter spikes are very common, recommended local Chamberlain protector and sent me brand new circuit board under warranty. This event proved that voltage spikes are common and dangerous even without thunderstorm.

You may want to do some research on Environmental Potentials products. I ended up purchasing a EP-2500 Waveform Corrector and a EP-2775 Ground Filter. These items are not cheap and require an electrician to install. However, when comparing the risk of loosing nearly $200,000 of equipment, what's another couple thousand?

Check the Audiogon archives and you will find quite a bit of discussion on their products. After I had the EP-2500 & EP-2775 installed, I could not detect any difference in the sound of my audio system, or in the picture quality of the projection system (thank God!).

Here's an interesting youtube link you may want to watch:

https://video.search.yahoo.com/video/play;_ylt=AwrTcdU5mpNUVbEACUUPxQt.;_ylu=X3oDMTBsOXB2YTRjBHNlYwNzYwRjb2xvA2dxMQR2dGlkAw--?p=ENVIRONMENTAL+POTENTIALS+youtube&tnr=21&vid=EBCBFAE3D09161E52A29EBCBFAE3D09161E52A29&l=272&turl=http%3A%2F%2Fts4.mm.bing.net%2Fth%3Fid%3DUN.608056142745044051%26pid%3D15.1&rurl=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D7SnyGCeju34&sigr=11aupo1lk&tt=b&tit=Environmental+Potentials+|+An+overview+from+Border+States&sigt=11plqnl22&back=https%3A%2F%2Fsearch.yahoo.com%2Fyhs%2Fsearch%3Fp%3DENVIRONMENTAL%2BPOTENTIALS%2Butube%26ei%3DUTF-8%26hsimp%3Dyhs-001%26hspart%3Dmozilla&sigb=13a16vl3h&hspart=mozilla&hsimp=yhs-001

Good luck on your search!
Ken G.

KiJanki, Do you mind me asking where you live?, I do not get power spikes like that here in Mobile,Al U.S.A., once in awhile, we may loose power on a sunny day, nothing has ever been damaged though, likly because I keep my equipment un-pluged when not in use, once the dropped power happened when my system was on, when the power come right back on, my amp simply was on stand-by instead of full power on, digital was simply off, all turned out good.

Audiolabyrinth, I live in Chicago suburb. My part of the neighborhood has power lines underground. We have rarely any power disruption.

I was going to plug my amps (tube main, SS for rarely used outdoor extension speakers) directly into my groovy hospital grade wall plugs (P.S. Audio) and remembered my simple power conditioner has some spike protection (thunderstorms happen) I don't want to give up...dedicated lines are a good idea, a diesel generator is insane unless you live in the middle of nowhere, and I unplug when out of town (in more ways than one). However, I still think scoring a surplus nuclear power plant from a mothballed sub is the way to go...if you have a water source running through the yard for cooling and some black market fuel you're all set...bribe the neighbors with free juice!