re-burn in? is there such a thing.

You know I think it does. I recently had to sale two of my CDPs (NAD C542 and Jolida JD100), and go back to an older (90s era) Onkyo changer that I hadn't used for about three years. Everything else in the system stayed the same. At first, the changer sound was somewhat thin, not a lot of body at all, and the soundstaging depth was almost non-existent. Recently I noticed that soundstaging depth and imaging had greatly improved, and that the overall sound had develped some decent body to it.

since i seldom use the cdp, i have trouble determining if it sounds worse then right after i burned it in for 200+hours. i've never been good at sound quality comparisons when they are separated by days or weeks....sorry but my ears and memory just don't work well enough to determine if something i heard last week or month sounds incrementally better then what i'm hearing today.

i use the system often so the amp and speaker burn-in doesn't really play into this situation. the cdp is the only component that sits unused for extended periods of time. when i do use the cdp, it's usually for 30 minutes up to an hour tops. i do notice improvements over the first 30 minutes or so. thus my question regarding a longer re-burn and does it get even better (like my friend suggests).

i'm not looking to "expound audiophile thingies" about anything to anyone. just wondering if i should make an effort to run my cdp for xx hours once a week or month or whatever??. hoping some of you with more experience (better ears and memory) can save me the time/effort of trying to figure it out on my own.

Well, Levy

You might want to do an extended run with some of your favorite CDs just to see. Over a two or three hour period, yours ears will tell you what you need to know. Bottom line, does your music sound right and if it does, then that's all that really counts.

My changer is run through a integrated tube amp, and I can definely tell over an extended period of time, that things ccertainly start sounding better. Now is it just the tubes or the changer, or some 'synergy" between the two, I really couldn't tell you. I just know the "toe tapping" factor goes up.

One thing I would suggest concerning your CD player is that you leave the Power ON. If you don't want to do that, at least turn the power on about an hour or so before you actualy start playing/listen to your CDs. Truth be told, components DO SOUND BETTER when they are fully warmed up.

There's a differnce between warm up and burn in.

Warming up is pretty obvious. Ask a race car driver if there's a difference between cold and warm tires. Similarly, some electronic equipment may have an optimal operating temperature for most efficient operation.

As far as burn in goes, people debate it. However, go to the nearest university engineering or science library and look for a book called "A Million and One Random Numbers". (I think that's the correct name). It's not too exciting. It contains a million random numbers. But read the preface.

In a nutshell, here's the story. In the early days of computers, scientists at Stanford University thought it would be good to develop a handy list of random numbers using the convenience of a computer to generate them. The result is the book. It's not always referenced, but pretty well every math or science book that has a table of random numbers at the back uses an excerpt of this book for the table. The scientists were concerned that the random generation of numbers by the computer could result in some numbers appearing more frequently at the start of the process. Just like flipping a coin ten times isn't going to always produce exactly five heads and five tails. It would all even out after time though. However, they had a concern. What if more frequently appearing numbers at the start of the process conditioned or burned in the electronic circuit so that those same numbers were more likely to appear in subsequent number generations? Then the numbers wouldn't be truly random. So they had to perform inferential statistical tests on the hypotheses that the numbers were or were not random. They had to regnerate some numbers because at times they were not confident that the number gneration was truly random because of the hypothesized burn in. They coudn't "prove" burn in but their inferential statistics couldn't always discount it either; so they had to take its possible existence into account.

Fascinating stuff. Anyway, I think it's hilarious when scientific types dispute burn in, and then they use textbooks with random number tables that were formulated with regard to the possibility of burn in. The irony is wonderful.

So, if you discount the possiblity of burn in, there's some pretty serious brain power and formidable statistical analyses a person will have to refute.

Components (of all kinds) basically burn in once when they're new -- but let me qualify that: this is true if what one means by "burn-in" has to do mainly with "setting" or "forming" the interfaces between conductors and dielectrics (not just wiring, but capacitors, diodes and many small devices. The only time this process MIGHT (depending on certain circuit design issues) need to be repeated, would be if one moved (as Rushton mentioned) and it turned out that the AC circuits for the audio system in the new house were on the opposite phase of the electrical service from the ones in the previous house.

Another instance of component "rehab" which I do perform on a regular basis (I'm just not sure "burn-in" would be the correct term) is using one of the many "system enhancer" CD's which supposedly remove residual magnetism and molecular stresses (Oy!) which build up in components, speakers, cables, etc. This could be identified as borderline snake-oil, were it not for the fact that most of them produce noticable results; except, for your cartridge/phono preamp, you'll need a record with a frequency sweep like the Cardas test record.

Speaker cables and interconnects should not need re-burning-in unless for some reason they accidentally (or on purpose?) get removed and then re-installed in the reverse orientation. Why? Because it's a bit like reversing a non-polarized capacitor in a circuit, and the interface between it plates and its dielectric have to be "re-formed" by the new signal polarity which (from the cable's point of view only) is now 180 deg. out of phase with the previous signal.