Every piece of equipment is different. Audio Research I have noticed has a very definite and incrediblly reproducible pattern (I broke in three Reference 160s amps… and 2 Ref Preamps.
But the real question to ask is, did your new unit sound great? If it did, forget about burnin. It is when you get a unit and it sounds closed in, harsh, and with ill defined bass that you have to calm yourself by saying… it need breakin.
My ARC gear needs roughly 120 hours to stop sounding trebly with poorly defined bass. Then it sounds great… then back and forth for about 40 hours. Then it reverts to sounding great…. And slowly improves to around 1,000,hours.
But every piece of equipment breaks in differently. So, unless it is not meeting your expectations, relax and enjoy your new piece of equipment… and I bet over time you will say, “wow, you know, that sounds better than when I first got it.”