Why does it take so many hours to brea in arc preamps and amps?

200 hrs will be a starting point for improved sound. By 400-500 hrs of listening time, one will hear where the time went in regards to continued sound improvement.  Teflon takes at least 600 hrs, more like upwards of 1000 hrs, to acheive optimum sound.  Sit back, relax and enjoy the journey.
Oh yeah, enjoy the Music as well.

Happy Listening!

When a designer is building a new product and makes changes, the component gets broken in before they listen to it.

I’m not talking prototypes, it’s production ones I’m referring to.
And the way your inferring is that the production ones are deliberately out of adjustment/calibration to factor in "break-in" period, which after those adjustment/calibrations are magically back in spec?? I think not.

To all those that say the manufacture has specified a certain "break-in" period, please link the rest of us to those manufacturers links, instead of it being just personal opinion.

Cheers George

@georgelofi

Yes, it was on a red warning sticker on the outside of the DAC 8. Well, not a sticker so much as a big red sheet taped to the outside. Clearly they intended buyers to see it before making up their minds. 

That DAC is long gone, and I had purchased a floor model from the local dealer, so I can't tell you if I thought that was real or not.

It not only claimed 500 hours for the DAC, but per input as well.

Best,

E

It not only claimed 500 hours for the DAC, but per input as well.

Sounds like Ralph’s "expectation bias" to me. By that time not only would a trial period be over but the warranty as well with some.

Still not advertised and written on a web page link by the manufacturer.

Just like the mains fuses that are "said" to have to be "broken in" and also to be 'directional" by manufacturers, yet try to find any of that advertised on a site by them.

Cheers George