Burn in question and evaluation before burn in

Thanks for the responses. Shadorne, your point is well taken, actually, what prompted me to ask the question was that I was frustrated that my new solid state preamp sounded good at first install, but became too bright, and strangely, the tight bass was gone too after a week. I know I had only like about 30 hours playing time on it, so it is not fully burned in yet, but I wish I can be assured that further play time would kind of reverse the initial burn in direction, if that is at all possible.

Cyclonicman,

My preamp was freshly installed with new upgraded board, it is supposedly better than the old version, but no, I have no idea how it will eventually sound.

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?

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 was a believer of burn in before, much more so now than before. When I started the thread two days ago, I noticed my new preamp turned from good sounding to intolerable after about 30 hours of playing. I played several my most familiar music, the treble was so bright and thin, and the bass was absent, that I had to check all my set up and connection to see if anything wrong; I found nothing and concluded the change in sound was most likely due to a certain burn in stage, I was not sure though, and hence posted my thread out of my curiosity.

After reading Albertporter's posts, and especially his prediction on burn in stages on transistor based design, I was more assured of that what I heard was not just my ears playing tricks on me.

After another 20 hours of play time since my first post, sure enough, the bass came back, and the treble became more focused and detailed. Actually, I found the bass is now actually a bit too much, I am hoping it would become slightly better controlled. Anyway, those are dramatic sonic changes in the last few days. I would easily dismissed the preamp if I only heard it during its worse burn in period.

Come to think of it, I seldom owned brand new equipment, and maybe that was one of the reason I did not experienced such dramatic burn in change before. Also, although the preamp was not totally new, the main board was replaced with brand new one, and that the unit I purchased came with brand new Linn silver interconnects and power cables, which I also put into use at the same time, all would attribute to more burn in changes.

If my current experience about burn in is jusitified, I would not judge a brand new equipment just because it does not sound good right out of box.

Burn in could certainly be conveniently used as an excuse by salesman or manufacturer when facing complaint about their product.

Re design with or without components with significant burn in drift, I do not have sufficient technical knowledge to decide which way is better, I am sure it is arguable. However, I think it would be very helpful for manufacturer to educate sales and the consumer how its products would change sonically after burn in. So for example, if I know a product would eventually be sounding brighter/darker than when it is brand new,then I have some fact to rely on in deciding if this equipment would be good for my system without keeping it forever, or well past the allowable return period.

On second thought, it is probably too much too hopeful for any manufacturer to do so. There is just so many variables, and there is no financial incentive.