Amp burn in time..just being on or music played?

OK, I'll go along with that. Sorry if I mistook your intentions.

I get defensive about high end designers and manufacturers as I get almost all my information from them, as opposed to reviews and popular trends.

I would never say that break in is a big issue on ALL components on ALL systems. Some equipment changes big time and some only a little. Add in the variations in quality of set up and system and you have a lot of doubt and confusion on the issue.

In my own system, it's always a big deal, unless it's something I've acquired used, in which case I get reasonably close to instant gratification.

With most amps merely having them on will exercise the bias circuits and open the path through the amp's channel. But there is very little signal (just noise) passing through so all of the components in the signal path aren't being worked, especially the passive components. Even the power supply is just idling. I have always felt the best way to break in any component with capacitors is to put a cd on repeat, turn the volume down, and let it play continuously for several days. My system is in a basement listening room so I can do this without angering she who should not be angered. This is fun to do. Going down for a listen each evening reveals how the sound begins to relax and become effortless as caps begin to come in. IME, the caps are always the long pole in the break in process. Usually between 150 and 200 hours.

I think Purist and Ayre have "burn in" discs that accelarate or, reduce the time needed to bring a component to its full maturity. If one believes that to be true then, in theory, playing music should be faster than just being turned on.

While we're on the subject, I, too, firmly believe in burn in (I had an issue with my esoteric which was discussed here on A'gon-took me over 1,000 hours!). My break in issue prompted me to send Robert Harley an email where I stated that if his reviewers advised how long they burned in their review samples, it would be a big help to us. He had advised that usually, his reviewers don't get to hold on to a review piece that long. His response puzzled me. I know 1,000 hours is out of the norm, but there must be other components which do take that long. Are reviewers reviewing their sample gear in the best possible scenario? I'd hate to discard a piece of gear because the reviewer didn't (or should I say, couldn't) let it burn in/break in long enough for the component to operate at its optimum.