Does EVERY component need break-in?

I feel that most everything changes with break in. Part of this could also be (in this case) from just having the unit powered up continuously for 3-4 days. I recently finished breaking in a Bel Canto DAC after it received the 1.1 upgrade and the sound fleshed and smoothed out considerably with 200+ hours of playing time (which exceeds it being powered up for 3-4 days), but I assume that both were contributing factors. As far as moving parts go, self lubricating bearings do operate more smoothly with use (which will cut down on vibration). I discovered this the first time as a kid when I made slot car frames and motors from scratch and raced them in competition. I just leave stuff on, use it and then hope for the best. I have never heard anything actually sound worse with break in with the exception of a Leviton Pro wall outlet that just got thinner and thinner in the midrange with use (I replaced it with an inexpensive P&S outlet which sounds much better overall plus has a much tighter grip on the plugs).

YES, Leave it on or in stand-by for at least a week before passing judgement.

Unplug your gear for a week, then plug it back in. Thin sounding? Absolutely. Give it several hours, and magically your system sounds just like it did a week ago. I've done this when I've travelled for extended periods of time, and also noticed the same effect when inserting a "new" piece of gear in my system (shipping time is generally over a week). Even used items need time to settle in and perform as expected. This may not be the technical diatribe some would hope for to prove that break-in is necessary but it certainly is easy enough to try for yourself. Unplug everything, wait a week or so, plug it back in. Proof is in the pudding. Jeff

Jeff L. I think that you're referring to "component warmup" vs. breakin phenomenon. Although this is more of a solid state issue, even tubed equipment containing solid state voltage regulators needs to be kept warm. It takes about 30 hours for the regulators to attain thermal stabilization, which is when things seem to sound best at our house. I only power down the rig for lightning storms, or for an extended vacation. I do turn off my amps on very hot days (although wish I didn't have to) because it makes a big difference in the A/C bill