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

You ask a perfectly logical question, but actually burn in time is not a function of either variable.

No, the correct burn in time is the minimum amount of time it takes to exceed your ability to return a component to the dealer if you decide you don't like the way it sounds.

How long is that time CWlondon...is it measured in minutes or hours, days or years in your experience ????

Buy the demo model. The work's already done.

Audiogon forums are filled with good testimony on the break in process for wire, capacitors and resistors.

Why would it be any different for a new amp with thousands of fresh parts to require some burn in time? Break in does vary a lot, depending on design and parts, but all amps get at least a little better and some A LOT better with time.

Actually Goliverjr may have thought his comment funny, but I my first pair of VTL 750 took a good while to settle and my second pair (very used) was up to 100% after a couple of days.