Burn in question and evaluation before burn in

Thanks guys! I did checked all wiring, connections, phase switches, etc., my conclusion was that the preamp has been and is still going through stages of burn in, or that my ears were playing tricks on me.

Actually, the sound from my system seems to be going the positive direction in the last 24 hour, that's good news.

From past experience, I know I should not make judgment on my preamp before it is fully burn in. However, the reason I posted the original question was that I would really like to find out if there are some general "burn in" knowledge could be learned. Like how tube, capacitor, silver wire, copper wire, etc. would behave during burn in process. I am also curious that is it, and how is it possible for a burn in to go in opposite direction in different stages? That is, for instance, for system to becoming brighter at one stage, and then become darker at another stage?

Wenrhuang,

Please read my post, the one above yours. Also, regarding:

I am also curious that is it, and how is it possible for a burn in to go in opposite direction in different stages? That is, for instance, for system to becoming brighter at one stage, and then become darker at another stage?

This is not uncommon and not far off what I posted before you said the system seemed to be headed in a more positive direction.

Unless you have a lot of hours, be prepared for it to go wrong again before it gets right. I know this seems improbable, but mirrors my experience in many situations.

Albertporter,

Your guess seems to be spot on, at least so far. When I first put my newly upgraded Linn Klimax Kontrol preamp back in my system, it sounded polite but precise, very musical actually; however, after about 30 hours playing, it turned to shrill with very little bass as you have guessed for a transistor based design. It became not enjoyable at all to listen to, and I thought something was wrong with my system. Only after another 10 hours playing today, I began to feel the music is slowly coming back a bit. I hope that my preamp would really smooth out and shine after 450 to 600 hours as you predicted may happen, again, for a transistor based design.

The preamp I have been using for the last two years is a Linn Klimax Kontrol. Linn just recently offered an upgrade kit---mostly new board(s)---and I went for it because I believe Linn would not offer it if not for real sonic improvement. I would of course rest my judgment until my upgraded preamp is fully burned in---(the kit and the preamp are not returnable anyway). And I will report back to you.

Anyway, my original post was mostly out of my curiosity about burn in, it seems to be a black art. But if your prediction is true, it means although a system or a whole equipment burn in maybe generally too complex to predict, there is still some basic component burn in rules to go by.

The kind of knowledge and experience you had is exactly what I am hoping to learn out of my original post.

I know of no contributions from Mr. Self that rival these
designs, In fact he's probably one of those that think Radio Shack, Cardas and
Nordost wire all sound the same with no audible effect on a high end system
and the music it produces.

Fair enough. Here is another comment from the
[url=http://www.theaudiocritic.com/downloads/article_1.pdf]Radio shack
camp[/url].

As far as I am concerned, I don't agree with Peter but I do suspect that too much
audio gear is based on inappropriate designs for the kind of precision needed to
avoid burn-in. (Examples are "no negative feedback",
"amplifiers with monster damping factors", "amplifiers with
incredible (and useless) flat bandwidth to several hundred KHz", designs
with "capacitors in the signal path" and so on and so forth...)

One thing I've learned over 40+ years is that initial impressions can tell you alot about a system and or it's componentry. If it sucks from cold, it may get less sucky, but it will not be transformed during the breakin process. If a system "WOWS YOU" in the gut from new, you are on the right track. Most aplogies and breakin stories come from people who have chosen poorly and can't deal with the awful truth (I've been there myself).