Amplifier warm up

I'm a bit skeptical of manufactures who say that their products need hundreds of hours of break in before performing or sounding good. Although some products do benefit from a break in period (several hours, not hundreds of hours) It has been my experience that good products will sound good and perform well out of the box (so too speak) after being allowed to warm up. I do know that some amps, pre amps DACs and CDPs (old or new and some more than others) will improve in sound after being allowed to warm up before giving a serious listen.

My, tubed pre amp sounds better after about 20 minuets of warm up, but I can't hear much, if any difference, after that. It just sounds really good. I shut it off when I am through listening, to save on my tubes and power bill, if I'm not going to be using it again for several more hours.

My Integrated tube amp sounds best after about 1/2 hour of warm up and I can't hear any difference after that. I also shut it off when I'm not going to be using it for several hours.

My old ADCOM SS power amp sounds best after at least 8 or 10 hours of warm up. When I'm using it in my main system, I leave it on continually. For those with these older ADCOMs, if you're not giving them at least 8 or 10 hours or warm up, you are missing out on how truly good they can sound. Many other SS amps, likewise, sound their best after several hours of warm up....Jim

Once again,  for the community's benefit,  read my article at Dagogo.com; 
"Audiophile Law: Thou Shalt Not Overemphasize Burn In", wherein I put both burn/break in and warm up to the test. 

I am uninterested in semantics arguments,  or debate with people lacking experience of actual comparisons of systems side by side.  :)

@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.
 

mitch2, thank you for your comments.

I have not used a cable cooker; there are simply too many things to do in audio that I have determined are of more significance to me. You can bet the first thing I would do if I got my hands on a cable cooker is repeat my experiment with sets of new cables to get to the bottom line regarding cable cookers.

If any cable cooker manufacturer wants me to assess, I can. But, I will vet the product first, as I will not spend extended time on a product that I deem of marginal value. If anyone wishes to extend that courtesy to me, they should expect that I will conduct a similar comparison as I did in the Audiophile Law article. That would be as fair an assessment as the come. :)

One last comment to perhaps head off objections. Someone might say that I'm predisposed to not hearing the benefit, as though my bias would not allow me to accept or acknowledge the putative benefit. Let's be more mature than that. I compare settings, cable sets, my Schroeder Method of IC Placement, etc. on a weekly basis, so if any change is to be deemed significant it has to pass my Law of Efficacy, which states that it must be instantly/immediatley heard, repeatable (i.e. In this case, heard concisely, even if cables are moved around), and subjectively benefit holistically, not just partially).

I leave my Pass Labs XA-60.5s in standby at all times, except storms and extended leaves.
They still take 20-30 minutes to sound their best (or maybe it’s the tube preamp).