I hate it when I am wrong. Or miss something. But that's life.
I don't play music through an amplifier or preamplifier that's burning in. The reason's simple. What's going on inside the amplifier is the forming of capacitors and the settling in of parts and circuit boards. Playing music hasn't much impact on those changes. Running current through the system does.
This flies in the face of Audiophile lore that states: music played through electronics burns in faster than just being on. Not sure I buy that and have never found evidence to support it.
That said, the same isn't true when we're talking about an entire system. And that's the point I have been missing. The key is not the individual electronics, but rather the connecting cabling.
Missed that.
Speaker cables, interconnects, and power cords need music playing through them to burn in. Why would this matter? We know different types of insulation materials impact sound quality: Teflon, Polypropylene, Polystyrene, Mylar all sound different. And we also know that as AC signals passing through cable dielectrics change state—and sound different.
Of the many cables in a system, the most important seem to be the speaker cables.
Many will say this is all BS. And that's fine.
But there won't be another show we attend without first burning in the cables with music.