beppe61 said:
Go back and read the final part of my post, I've just edited it.
http://www.diyaudio.com/forums/showthread.php?postid=774200#post774200
janneman said:Oh yes I do. Unless you have been genetically manipulated. Are you?
I don't know!
janneman said:
Jan, you must be talking about this:
janneman said:
That's not what I said, and I think you are up to one of your little traps.
You are manipulating my words, and there's no time and patience to refute everything.
But we have discussed this so many times, why hit the same key again?
Hi beppe61,
The decrease of PS capacitor ESR with temperature elevation is a very real phenomenon and certainly contributes to a smoother sound in PS sensitive amplifiers but the capacitor ages rapidly usually manifesting in a 'soft' bass sometimes, in a cooking chassis, after only 400 hours from new. The lifetime of many of yesterdays capacitors was only 1,000 hrs @ 85C or 2,000 @ 75C but deterioration near heatsinks is worse.
If you look at my module kits I use only 105C rated electros near the output stage and most of the board so the C's last. I wouldn't go to the extra expense unless I believed it. The power supply C's get it much worse with very high diode charging currents causing local heating and ageing. That's why I have used smaller multiple paralleled C's to split up and distribute the heating, for example -
http://members.dodo.com.au/~gregball/guru_008.htm
No matter who is in denial, the physics is real.
Cheers,
Greg
The decrease of PS capacitor ESR with temperature elevation is a very real phenomenon and certainly contributes to a smoother sound in PS sensitive amplifiers but the capacitor ages rapidly usually manifesting in a 'soft' bass sometimes, in a cooking chassis, after only 400 hours from new. The lifetime of many of yesterdays capacitors was only 1,000 hrs @ 85C or 2,000 @ 75C but deterioration near heatsinks is worse.
If you look at my module kits I use only 105C rated electros near the output stage and most of the board so the C's last. I wouldn't go to the extra expense unless I believed it. The power supply C's get it much worse with very high diode charging currents causing local heating and ageing. That's why I have used smaller multiple paralleled C's to split up and distribute the heating, for example -
http://members.dodo.com.au/~gregball/guru_008.htm
No matter who is in denial, the physics is real.
Cheers,
Greg
carlosfm said:I don't remember the model, but it was an AV amp, slim model, that cost around 300€, two years ago. Not bad at all. Tested with a pair of Monitor Audio floorstanders, in stereo.
The same for the Jadis.
Really, the Jadis sounded bad. Bad, bad, bad.
I don't understand the fuss.
Besides making a metal string acoustical guitar sound like a toy with pastic strings, I could even hear the hum 3 meters away from the speakers.
Dear Mr. Carlos,
thank you so much for your extremely interesting advice.
I do not like hum at all.
Noise is noise.
Thank you very much again.
Kind regards,
beppe61
just to clarify ..I'm refering to the burn in TEST procedure.. in my other post.. not burnin to sound better..
regarding burnin to make something sound better i think it acually must depend on the original design too.. with a little bad luck something burnined might sound worse too,not too often i hope hehe. just like a speaker might be designed for long high ohm speaker cables ,hehe
I'm currently experiencing "burn in" of my new amp but i dont expect to hear a difference.. certainly i think some new components might change a little in time and heat,but I just play music and if my new ring radiator tweeters sound better after a year that's fine but still more than 99% of my records already sound bad in comparison so it's a minor problem, but it's not really a problem any more because the sound in my new amp matches the tweeters very good i think, by beeing a bit soft.. (not slow, it still shows a reasonably good 15khz square wave on the scope.)
regarding burnin to make something sound better i think it acually must depend on the original design too.. with a little bad luck something burnined might sound worse too,not too often i hope hehe. just like a speaker might be designed for long high ohm speaker cables ,hehe
I'm currently experiencing "burn in" of my new amp but i dont expect to hear a difference.. certainly i think some new components might change a little in time and heat,but I just play music and if my new ring radiator tweeters sound better after a year that's fine but still more than 99% of my records already sound bad in comparison so it's a minor problem, but it's not really a problem any more because the sound in my new amp matches the tweeters very good i think, by beeing a bit soft.. (not slow, it still shows a reasonably good 15khz square wave on the scope.)
if a piece of audio gear has to burn-in to sound good than it was broken to begin with. every electrical component is made with the design goal to minimize change over time, and if is used within spec very little will change. only in "audiophile land" are claims made that burning something in will result in a wild change in spec (always for the better for some reason?). the only thing that ends up burning in is your ears(minds) ability to grow more comfortable with what you are hearing.
Yes part of high reliability design and production is to burn in across the operating temperature range. The aluminum parts with a high coefficient of expansion will obviously expand and contract quite a bit. Marginal wire bond welds might break and so on. It's a good way to eliminate marginal components and even design issues.
Most of my design work was to high reliability specifications.
I wouldn't call reforming caps burn in, but it can be a real problem for caps that have been unused for a long time. I find that often they do not need reforming, even 30 year old caps, but have seen a few on occasion.
There is some interesting information on reforming electrolytic caps at the end of this page. Section 2.10 is a life test showing 1000 hours at full temp and voltage:
http://www.duracap.com/electrolytic_capacitors/application_guide.htm
Pete B.
Most of my design work was to high reliability specifications.
I wouldn't call reforming caps burn in, but it can be a real problem for caps that have been unused for a long time. I find that often they do not need reforming, even 30 year old caps, but have seen a few on occasion.
There is some interesting information on reforming electrolytic caps at the end of this page. Section 2.10 is a life test showing 1000 hours at full temp and voltage:
http://www.duracap.com/electrolytic_capacitors/application_guide.htm
Pete B.
it seems quite pathetic to me that this burn-in technology most widely used for semiconductor devices as a test process was hijacked by the audio salesmen.
i have heard anecdotes wherein buyers were made to hold on to tube items for 100 hours burn in.
i believe burn in is the responsibilty of equipment makers and not the consumer.
i have heard anecdotes wherein buyers were made to hold on to tube items for 100 hours burn in.
i believe burn in is the responsibilty of equipment makers and not the consumer.
Burn-in is only effective for our own lousy human hearing due to its extremely adaptive nature. Modern high quality solid state electronic components don't suffer any performance drift with time worth considering, while our hearing indeed does.
You may keep a transistor amplifying some current within its ratings for 100 years, and at the end it will exhibit very slight drift from original parameters (if it does not fail prematurely). On the other hand, you will be dead and no longer able to hear anything after 100 years. Even after only 50 years you will have lost most of your hearing if you are still alive.
You may keep a transistor amplifying some current within its ratings for 100 years, and at the end it will exhibit very slight drift from original parameters (if it does not fail prematurely). On the other hand, you will be dead and no longer able to hear anything after 100 years. Even after only 50 years you will have lost most of your hearing if you are still alive.
Well, but the point here is that the thing that changes during these claimed burn-in periods (be short or long) is the hearing of the user, and not the performance of the electronic equipment.
It's quite an arrogant (audiophile) practice to consider human body and mind as an absolutely perfect thing and blame everything else in the world (but that's probably a more deep issue ultimately related to religion).
It's quite an arrogant (audiophile) practice to consider human body and mind as an absolutely perfect thing and blame everything else in the world
(but that's probably a more deep issue ultimately related to religion).
Wow, all these posts arguing about sonic benefits of burn-in.
Yet, it is interesting to note that Charlie Hansen (of Ayre) was quoted in Stereophile (by Sam Tellig) that even individual channels of a preamp has to be burned in.
I have nothing against burn-in, just find it hard to hear differences (if any) on good quality gear.
Yet, it is interesting to note that Charlie Hansen (of Ayre) was quoted in Stereophile (by Sam Tellig) that even individual channels of a preamp has to be burned in.
I have nothing against burn-in, just find it hard to hear differences (if any) on good quality gear.
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