In the Fall 2000 issue of The Audio Critic magazine, Peter Aczel wrote:
The Burn-in Lie
“This widely reiterated piece of B.S. would have you believe that audio electronics, and even cables, will “sound better” after a burn-in period of days or weeks or even month (yes, months). Pure garbage. Capacitors will “form” in a matter of seconds after power-on. Bias will stabilize in a matter of minutes (and shouldn’t be all that critical in well-designed equipment to begin with). There is absolutely no difference in performance between a correctly designed amplifier’s (or pre-amp’s or CD player’s) first hour and 1000th-hour performance. As for cables, yeccch… We’re dealing here with audiophile voodoo here rather than science.
Loudspeakers, however, may require a break-in period of a few hours, perhaps even a day or two, before reaching optimum performance. That’s because they are mechanical devices with moving parts under stress that need to settle in. (The same is true of reciprocating engines and firearms.) That doesn’t mean a good loudspeaker won’t “sound good” right out of the box, any more than a new car with 10 miles on it won’t be good to drive.”
Audiogoners, do you agree? Sound off in the comments below!