Well, as yet another EE, I'll weigh in.

I used to believe that was no such thing as burn in until a couple of weeks ago when I upgraded all of the capacitors and resistors in my main speaker crossovers.

I'm using Polk Audio SDA SRS's. The "SDA" stands for Stereo Dimensional Array which just means that they eliminate interaural crosstalk. Half of the drivers on the right speaker are driven from the left speaker (there is an interconnecting cable) and out of phase as to cancel what your right ear hears coming from the left speaker. Same deal with the left speaker. The purpose is to widen the soundstage and add depth (think headphone-like sound from your speakers). It works. Well, it did, until I upgraded the crossovers, after which the effect was noticably diminished. After about 10 hours of play, it started coming back. I attribute this to the capacitors in the crossovers burning in. I never would have expected it, but there it is.

I still don't believe in speaker or interconnect cables needing burn in, or solid state devices, but there's something going on with those capacitors...

Cary