Does a brand new electrical circuit for audio gear benefit from burn in/break in time?

they do not reseat all connections, power and signal

I will certainly give that a try, @ieales  .

There's no such thing as a burn in time, in the sense that an electronic circuit behaves differently after say 100 hours of use.

There can be a temperature effect though. An amplifier (and also other equipment) warms up when switched on. All components slowly reach their stable temperature and the electronic operating point that belongs to that temperature. Depending on the circuit there may or may not be subtle audible differences between cold and warm operating state. Some prefer to keep their gear switched on 24/7.

^ +1

Unless one lives in an ice box, flipping on the HiFi and playing a track or two while brewing an espresso, pouring a malt or similar, gets the circuits close to idle temperature or better. [class A excepted]

Unless the power amplifier is defective, voice coils & passive XO are at ambient temperature. Temperature changes in these may have more sonic impact than the electronics.

For the vinylphiles, exercising the armature may also benefit.