warming up the system

According to Pass Labs they recomend at least 1 to 1 1/2 hours for there amps to get up and running.

"but a good rule of thumb is just past the time for the warranty to expire."  Classic!

Warm up for an AB amp is usually 20-40 minutes.  For a Class A amp, it can be much longer.  My experience is tube amps usually warm quicker due to the direct heated nature of most triodes.  I find my amps are warmed after about 20 minutes.  It is audible and obvious when they cross the line.  

Break-in of cables depends on the brand.  Clarus burns things in for a solid 200 hours.  Others may be longer or shorter.  

As to a solid state amp if you have measurable or auditory changes in the performance of the amp after it has been on for 2 seconds, then you paid too much for it, whatever you paid.

All components on a circuit board are rated. Those ratings are established once they have warmed up and stabilized from a cold turn on. Once they reach that optimum operating temperature range, then it works as intended, and that takes a lot more than 2 seconds.

Same for tubes.

All the best,
Nonoise

Sounds great after “on” for 20-24 hours, also on and warming up are the preamp, CD player. 
 After 40 hours, the difference is astounding, there is a laserbeam 10 feet wide wall of sound, where the vocals, and especially the midrange and small 6.5” woofers, mesh perfectly and still give me goosebumps, on arms, and I love when my head tingles!!

 If it’s snake oil, it’s very good snake oil!

 Speakers took about 300 hours to relax and really shine, a lot of people don’t allow break in for speakers…

I waited the manufacturer recommended break in period, and I was rewarded greatly!