Amplifier warm up

If you played side one from a cold start, it would be surprising if the hour of warm up didn't improve the sound.  MC nailed it.....leave your SS amp turned on. 

My new SMc Audio monoblocks do not have a power switch, just power cords to the wall.  Steve McCormack recommends leaving them turned on for best sound and turning them off for:

• storms and potential power outages
• vacations
• other periods when I do not plan to listen for extended periods of time

Not every amp is going to behave the same and maybe not every amp is thermally suited to remain on all the time....like my former 300wpc Class A Claytons.  I have heard the on/off cycling can be harder on the circuitry than leaving them powered up but.....who knows?

@douglas_schroeder  - I read the article and am not surprised with the results.  Since I don't view these things as a contest, I am not concerned that some here believe in significant changes due to burn-in, but I don't.  I think you are getting close to what happens with your statement:

I would assert that a significant change happens to the hearer during the honeymoon period as the ears acclimate to the product. Why is there so little discussion of “Acclimatization”?

Could this be a reason some manufacturers recommend an extended burn-in period before making a decision about the sound quality of new equipment?  Considering some combination of The Endowment Effect, the Sunk Cost Fallacy, or some other psychological phenomenon, some manufacturers (or their marketing departments) probably realized the longer a person owns something, the less likely they are to return it.

While I don't believe in extended burn-in, I have heard the difference between an amplifier that is warmed up vs. one turned on from a cold start.  The difference was apparent with my former amplifiers - Class A Clayton M300s.  They were most of the way there after about 30 minutes and seemed fully on task after an hour.

As a follow-up to your burn-in article, I would be interested in hearing about whether you and David could hear differences between brand new cables and cables that have been conditioned on something like the Cable Cooker.
 

Thanks for that information @slaw. Steve hadn't told me that but he put two big low noise Plitrons in my SMc Audio DNA-1 UltraG-20 monoblocks earlier this year.  That may be why he offered the option of having no on/off switch.