Burn-in is critical for just about every audiophile product… This applies to Cables, Components, Speakers, Turntable Cartridges, etc. We won’t attempt to explain this phenomenon but on a high-end system you can hear the sound change over time even with a power cable to the preamp or another component. Inadequate burn-in is the most common reason for the returns we receive, which is why we provide a rough estimate for each product listed in the Jaguar Online Store.
There are no set rules or guidelines for how long this takes. Generally, the more current flowing the faster but one DAC may take twice as long as another. Sonically, inadequate burn-in usually manifests as an anemic AM radio sound, as if the high frequencies are bound up and lacking spaciousness. Generalizing again, you may get good sound for the first few hours, then it goes downhill, and once you reach the final moments things can sound strange and for about 15 minutes as you finally break through the resistance you may even get the idea that something is wrong somewhere in your system. This process can be sped up with cable cookers and with a burn-in file.
Here is a free Burn-in file download at the link below. Load the burn-in to a DAC or even a phone and play it through the device. You don’t need to play the file through your speakers unless the product in question is a pair of speaker cables or speakers, in which case you can just play the track at moderate volume. This can cut burn-in time by 50% or more. You can also use the file every few weeks to refresh your system, as the white noise will demagnetize static electricity that has built up over time.
Here’s another link to a 6Moons article on this topic and it even includes an endorsement from Gary Koh, Owner of Genesis Loudspeakers, who knows a thing or two about burn-in.