Break in for new DAC

Burn in is kind of like cables-an unresolvable debate. My ears are fine and my gear is fine and I've never noticed much change in new electronics during any "burn in" time. Speakers, things with moving parts may be a little different-mechanical devices. That's just my experience. If someone else has a different experience-whether its the electronics or their brain that is burning in-I wouldn't take issue. Its foolish to try to tell someone else what they hear, even though its often tried.

What can you do if the sound of a product changes during burn in until it reaches perfection to your ears, but then it keeps burning in and keeps changing in a suboptimal way? Logically, that would happen since we all have different tastes and ideas of what constitutes the sonic optimum and you would have no way to stop the burn in at precisely the right time.That would be frustrating.

The good thing about burn in, unlike cables, switches, crystals, etc., is that it doesn't really matter which side is right. If burn in really happens, you can't stop it. If it doesn't, you can't force it. Nothing to buy, or not, so all is well. Unless you hang on to something that doesn't sound good beyond the return date. Don't do that.

At any rate, it happens or not without any intervention from us, so no use getting the nasties over it. Smart people on both sides of this one.

Life's a biartch and then you die.

does the amp really need to be on?

Few have addressed this point.  The DAC does push some electricity towards the amplifier, and the amplifier presents as a load to the DAC.  So why not create an equivalent dummy load from resistors just in case electrons really can create a burn-in effect?

I am reminded of a radio skit from John Cleese and others, about a letter to an Agony Aunt in a women's magazine:

Dear Marge

I am worried about my son.  He is growing something in his window box which he says is cabbage, but I think is marijuana.  What should I do? Yours, Worried.

Dear Worried

try some and if you are still worried, it's cabbage

Generally speaking, most equipment needs break-in to sound best, in my own experience.  200 hours or more for your DAC would not seem unreasonable to me, which will happen naturally over time as you use it.  I would not leave the tube equipment on for that long just to burn in the DAC.

"most equipment needs break-in to sound best"

not really, aging (break-in), increases digital circuits jitter/s, negatively impact switches/drives strength.