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


I recently purchased a like new ARC 5 SE pre amp.  The unit had less than 200 hours on it.  Everything I have read states that ARC preamps take up to 600 hours to fully break in.  Why is this so and what improvements can I expect to hear as the unit accrues hours?
ewah
To Randall-11

I have lots of practical and theoretical, working in the Aviation world in avionics, I also am a certified Machinist and fabricator. I have rebuilt and restored many audio units, reel to reel recorders, tape cassette, amps, preamps, etc... Designed my own gear, built many varieties of cables and so forth. 
But you may have known that if you actually read the post rather than breeze through and develop your usual assumptions and then criticize others. 
For those of you who cant build their own gear, the lack of real experience tends to make you more prone to believing whatever sounds most convincing or has been kicked around in forums here and there. 
You can speak with the moderator about your comments, they know about them and so do you. Have some respect and manners speaking to members.
you're telling me that sophisticated measuring equipment wouldnt show a change to demonstrate what you are describing as bloom or whatever audiophile terminology you want to use?
@dchang1981

I do believe this is possible, but not common. It needs time domain measurements, patience and LOTS of data.

Audio measurements are too often really simple things. Steady state sine waves, sweeps, square waves. There are a lot of tests which go ignored or under used. I'm not saying I have proof, but I am saying I think a good data scientist/engineer could eventually discover.

For instance, in speakers, dynamic range/compression is rarely tested by magazines, but it's one measurement I find describes a great deal of what I hear. Perhaps some day I'll come up with cap sound measurements and they'll name it after me. :D :D

But proof, no. Experience, somewhat. I'm not really interested in forcing the issue on anyone though. A skeptical open mind is always a good thing.

Best,

E
"A skeptical open mind is always a good thing."

Interesting how a skeptical mind is often at odds with the open mind, no?
anybody can build their own gear

anybody can read a textbook on cognitive psychology too (well, ok not everybody...)

I agree it would be hard to measure a change - tho one could arrange a blind listening test to show an effect w/o knowing any mechanistic reason for the effect
but...
if ARC says to do something, why not do it?

for my ARC pre-amp it warms up for about 40 seconds - could be tube protection tho, not SQ