Amplifier Break-in - It's Real


I just completed a major amplifier upgrade from using the power amp side of a NAD 375BEE integrated to a Coda No. 8 and can swear to reality of a necessary amplifier break-in period and the need for a great degree of patience. For the record the 375BEE is a great integrated and the power amplifier side is very good. I replaced the preamp some time ago with a Freya+, a significant upgrade. Regardless, the 375BEE has some limitations and I "needed" an upgrade. I have severe space restrictions for my gear/rack, so size mattered, and final candidates were Bryston and a latecomer in the Coda 8. The Coda had such great reviews/comments I went with it.

Days 1, 2 and 3 were pretty frustrating and I was concerned. My NAD setup had a very good sound stage and rich bass, neither of these were evident early on with the Coda. I thought it might be an impedance mismatch with the Freya (75 SE or 600 balanced ohm output) and the Coda. Some online specs show the Coda at a very low 1K Ohm input impedance, however before I bought I checked with Coda and they confirmed it is actually 10K ohms. Still I swapped out the new balanced cables for RCA's, no significant change. For the first few days I was turning on the amp in the morning and running it all day, but off at night. I decided to have patience, accept the need for break-in, and just start running 24/7. Lo and behold about three days into that process, during which I found some new respect for electronica, the sound stage and bass started to appear and have only improved. It was uncanny. IMHO there was no way I was imagining this change because contrast was so great from the NAD when I first plugged the Coda into the system. I know my system well and changed nothing else, aside from the noted interconnects, from one amp to the other. I realize I am mostly preaching to the choir, but am writing for the next person that plugs a new amp in and does not hear what they expect right away.

In case it matters, the rest of the system is KEF LS50, Gumby DAC, REL 7i sub and Pi 4 with Allo DigiOne running Moode.
zlone
Solid state can take days to stabilize and should always be left on. Just leave it on for a week or two, then turn it off one night, you will see.

That is my next test. I have been assuming that I am witnessing break-in and not just the need to warm up/stabilize. If the amp has to be on for days to sound right it may not be the right piece of equipment for me. I live in a cold climate, but still not comfortable leaving a power amp on 24/7 as a space heater. My previous amp would take about 30-60 minutes to get to a good place, I am sure it improved with more time, but it did not take days.
@millercarbon. Talking to Constantin @atelier13 in Nashville the same is true though to a lesser degree for tube amps.

Iron is iron and the transformers need heat cycles through the iron as do capacitors and valves or tubes.

I have a AH Qualiton X200 arriving this coming week and have had many discussions about tubes and tuned equipment with him. He has a very interesting background and is another great resource for data on Tubes and Tubed equipment. He is on scale with Dave @ Raven and Kevin @upscale. 
https://www.atelier13-usa.com/about-atelier-13-audio
My SS AMPS sound so much better when turned on 24 hours before listening.  If I listen on Friday or (and) sat night, I will power on Thursday morning at 4 am before I leave for work, they are on all day Thursday, and Thursday night, for jamming on Friday and sat, the sound is night and day for me.  The laser beam sound is so distinctive, compared to listening cold. 
 Amp, preamp, CD player, all powered on this way.
there is a massive difference between cold listening and the warm up sound.  
 Same with my 2nd system, they need a bit longer, the Odyssey amps do need a good 48 hours+ to warm up to sound their best.
   I remember the initial odyssey warm up, it did take well over 4+ months of program ,   Was really odd,....I remember listening on several occasions to many cds and pls’, and the sound,....

it was so different, sometimes, weak midrange, sometime in your face midrange, treble sometimes, super bright, other times relaxed and warm,   Same with the bass, deep, not deep, tight, muddled, 
   It did take a long time, was nice to. Have my brothers system to listen too while those odyssey’s did break in.   Been through a lot of amps over the years, these odyssey amps are the only ones to honestly sound so different at so many times of break in.
    Very strange! They do sound amazing now, only takes  a couple days now to warm up, maybe 3 days.   They do sound amazing!
some of the best I’ve heard.

  Warm up is real, I love the sound signature between the cold sound and a 24-48 hr warm up.
       There is a laser beam effect I get when warmed up, music just flows naturally from my speakers.
   I like the difference, even the wife notices the music difference after a warm up, especially with her fav albums, ,...hysteria, the wall, holy diver, there is a massive difference. 
You, and everyone who thinks they hear equipment breaking in, need to read my articles about this topic at Dagogo.com;

Audiophile Law: Thou Shalt Not Overemphasize Burn In

and 

Audiophile Law: Burn In Text Redux 

The community needs to gain some perspective on how much of a range of perception humans have from day to day while listening. It's complete nonsense to think that we are more consistent than electronics, or that we can definitively assess changes to systems over days, weeks, etc. A great deal more humility/experience is needed in the audiophile community.    :(

Enjoyment/perception of an audio system can change significantly, while there is no change in actual performance. This should be obvious as a result of establishing a very pleasing system and hearing more music on it over time. I have this experience perhaps two dozen times each year as I set up discrete systems and adjust to their performance.   :) 
it was so different, sometimes, weak midrange, sometime in your face midrange, treble sometimes, super bright, other times relaxed and warm,   Same with the bass, deep, not deep, tight, muddled,
Thanks for your post, I am experiencing some of the same. I do want to note that none of this is a knock against the Coda, it has delivered a lot of what I hoped for, just taking a while.