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
Just to wrap this one up, after a month or so of continuous play I have to say the Coda 8 is a spectacular amp. I still feel strongly that there was a break-in period, not just a case of warming it up for few days. I can now shut off my equipment for a couple days, turn it on and get good sound immediately and great sound within the hour. Not something I could do when it was fresh out of the box. No doubt it improves if left on for longer. Thanks for your comments!
I would be interesting if someone bought a new pair of monoblock amps and burned in one amp and then compared the two. I bet the sound difference would be very audible between the two amps.
I would be interesting if someone bought a new pair of monoblock amps and burned in one amp and then compared the two. I bet the sound difference would be very audible between the two amps.

THAT would be an interesting experiment!
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.
@douglas_schroeder  A long time ago we documented the apparent 'break-in' phenomena that we were clearly experiencing in the shop. It turns out that you can measure it- over the break-in period distortion drops off and bandwidth opens up as the filter capacitors form up. We also documented small changes in the power supply voltages, which seemed to correlate with the form-up time of the filter capacitors. We've noticed also (some of this anecdotal correlating our own experience) that if the electronics is stored over a long enough period, the filter caps will lose their form, at which point the unit will appear to need to 'break in' again. However, not wishing to go down the rabbit hole, we did not document if/how other parts might be affecting this process- part of the problem being how to test something like a resistor for such a phenomena (which on its face to me sounds ridiculous). But capacitors forming up is well-known.
break in is definitely real (and the human psychological element is present too, no doubt... both can be true simultaneously)

but for different types of gear, the degree of change over time can be quite different... as different techincal elements may take shape differently as used hours accumulate

trust your manufacturer’s info on this topic