Amplifier Burn In

[SKR]

I was just going thru the web site of famous audio brand from switzerland FM Acoustics. And while going thru product details of their Classic Amplifier range, they have mentioned quote " RIGOROUS 200 HOURS( 1000 THERMAL CYCLES ) BURN-IN OF EACH AMPLIFIERS "
So they are burning each of their Classic series amplifiers for 200 hours in their factory before final packing.
I am sure there was no need of doing this if Burn-in was not required or not important ot meaningful.
FM Acoustic amplifiers are world class and they do not belive much in advertising and have select customer base.
Will request those not believing in Amplifier burn-in to visit FM acoustic web site and if they feel convinced can change their mind.

 

[venkatcr]

Will request those not believing in Amplifier burn-in to visit FM acoustic web site and if they feel convinced can change their mind.

The burn-in at FM Acoustics is part of their testing process to ensure each and every item meets their set standards. I quote from their web site:

12. BURN-IN

The custom-built testing machines at FM ACOUSTICS meet every possible demand. Besides standard tests such as distortion analyses, noise measurements frequency response etc. other special tests and measurements performed by these machines include the following:
* A wide variety of switch-selectable loads
* Accurate voltage and current measurements
* High voltage insulation tests
* Wave from tests
* phase linearity tests
* Attenuation accuracy tests
* Thermal tracking and operation measurements
* Thermal overload tests
* Multiple specific error generation for checks of protection circuitry
* D.C. offset tests and calibration
* Ultra-accurate CMRR measurements
* Transient behaviour tests
* Multiple burst measurements
* Short-circuit tests
* Precision RIAA and de-emphasis
* Precision filter measurements
* And more...

After each product has been pre-tested and performs perfectly, and after all data have been recorded, the unit is then moved to the specially built burn-in room. There it is exposed to a long-term burn-in test running under the most severe test conditions, this for at least 200 hours in a thermal multi-cycling mode. These cycles are programmable from a few minutes up to several hours. The units consequently heat up and cool down repeatedly, going through between 1000 to 2000 full thermal cycles. In this manner worst-case test scenarios and heavy-duty burn-in (including the important pre-aging) are achieved and the possibility of later malfunctions and defects is virtually eliminated.

The burn is specifically to heat up the units, cool them, and then heat them again to see how they perform. This process also helps in artificial ageing of the units. All this is done for what? To ensure the specs are met. Nowhere does it say the burn in is to improve the sound.

Pay attention to the words, 'possibility of later malfunctions and defects is virtually eliminated.' Actually given the rigorous specs and R&D that they perform, I am sure FM Acoustics designers and engineers will ensure the sound signature never changes.

This only solidifies my point. Thank you.

Cheers

 

[jaudere]

The burn-in at FM Acoustics is part of their testing process to ensure each and every item meets their set standards. I quote from their web site:



The burn is specifically to heat up the units, cool them, and then heat them again to see how they perform. This process also helps in artificial ageing of the units. All this is done for what? To ensure the specs are met. Nowhere does it say the burn in is to improve the sound.

Pay attention to the words, 'possibility of later malfunctions and defects is virtually eliminated.' Actually given the rigorous specs and R&D that they perform, I am sure FM Acoustics designers and engineers will ensure the sound signature never changes.

This only solidifies my point. Thank you.

Cheers

Well cought!:clapping:

 

[Asit]

Hi Venkat,

Let me tell you with a deep conviction that all the parameters for the performance of an amplifier are NOT known. I have described the problem in reasonable detail here and in my amp thread. An answer like "the unknown factor is the designer's ear" only substantiates the doubt. Unless they are completely known, people can speculate matters to their liking. There is no harm in that as long as we respect each others' views and real experiences formed over a period of a few decades.

Correct me if I am wrong, but I have never seen a thorough investigation of the spectrum of the sound and its change when a signal passes through a passive component like a cable. I have read tons of discussion on the impedance, inductance, percentage loss of signal, percentage of noise etc, but among the most important effect of the material medium on a propagating signal is change of the spectrum, and I am yet to see a measurement on that. As mentioned by Cranky, passive components like cables and capacitors are the ones mainly responsible for a break-in (or a burn-in, not sure of the correct terminology).

CDP manufacturers had us believe the sampling theorem so much that people think a redbook CD format is guaranteed to reproduce the original unquantized signal completely. There is no problem with the sampling theorem, it is correct, however the conditions under which it is proven are never applicable in real life situation and as a result there are well-known artifacts discovered about 100 years ago. My point is, there is science, but when we implement that principle in a real life situation (as in engineering science), there are always artifacts of that situation and things become quite complicated and yes that happens even for the best designers, and as a result we hear occasional call-backs (although unheard of in India) of certain engineering products for suspected or documented malfunctioning.

I would like to know what is the "important pre aging" that the famous manufacturer is talking about in your quote in your post above. In addition, I would also like to know a bit on electrolytic capacitors and any change of their behavior with time. I briefly looked up on the net which is filled up with descriptions of burn-ins of these capacitors. I would just like to know your opinion.

I would still respect your actual observations of no break-ins of amps in your personal experience, as I already said in my previous post. It is only ironical here to mention that on the net many people are also arguing about this issue and many people see the break-in and some do not. I guess, as Cranky already noticed, in certain constructions and also because of a factory break-in (or some other yet unknown reasons), certain amps may not go through a noticeable or significant break-in in a customer's home. While we have received a great contribution from you regarding some of the basic functioning of an amplifier, and I have fully understood your argument, but despite that I tend to think that your arguments are not conclusive enough to say that ALL amplifiers do NOT break in. And I still think your answers to my questions 1 and 3 are unsatisfactory.

Although hearing is subjective, but for a given person (unless he/she is very old or a few days/weeks old) the hearing is largely consistent. I will not doubt our ears so much as some of us would like to believe, especially when it is used as a convenient cushion for an argument.

I think this has gone now too long and too far, and we are so much into speculation to prove our point that I feel I have no place here.

Regards.

 

[jaudere]

Hi Venkat,





Although hearing is subjective, but for a given person (unless he/she is very old or a few days/weeks old) the hearing is largely consistent. I will not doubt our ears so much as some of us would like to believe, especially when it is used as a convenient cushion for an argument.


Regards.

Hmmm,
Asit , Do you believe in " development of the taste" for a particular food? the tongue remains same but the liking changes over a period. There are some songs which you gradually start liking . I have noticed this especially with Rehman songs.The more you listen , the more you notice beautiful spots in it.

The ears perform consistently but the brain may not! We interpret music in brain and not in ears.there is something called as "affect" in medical term. e.g. if someone pinches you, you feel pain. everybody will. but the emotions which you and the other people develop & express may be different to the same pain. so the emotion which you develop due to a particular stimulus is called as "affect" which is certainly different than the actually feeling the touch or feeling a sweet taste or smelling some fragrance. Just like an amp or any other gadget, there is circuitry in brain which is probably breaking in throughout the life.

So the end conclusion: few believe that the amplifier circuitry breaks in and few , like me, believe that the brain circuitry breaks in (though nobody has mentioned it in words). So everyone wins here. You need breaking in somewhere. Both may or may not be true. you can never determine it unless measured by objective measurements. At least i don't know of anything where burn in was measured objectively. So experts, please throw some light on this aspect.: objective measurements for breaking in an amplifier

 

[jaudere]

A subquestion: How do you measure the timbre of a sound? because i think this breaking in, if at all, affects timbre rather than amplitude and frequency.

 

[Asit]

Hi Jaudere,

Sure, all signals we receive are analyzed at the brain, why only sound and music. Development of music taste that you are talking about is a very interesting subject, I have experimented with a few close friends of mine especially on this topic, and was able to convert them completely, musically. If you want to know the details of that, we have to take that discussion to another thread, because that will be too much outside the topic of this thread. But please note that, this happens over a much bigger span of time (a few months at least, usually a few years in my experience) than the usually anticipated time of an amplifier break-in (a few tens of hours, in my experience). That's why I would tend to think that the taste-development is largely irrelevant for the discussion here.

Sine you mentioned this sort of thing, let me mention that especially in the context of Indian classical music, there is a saying that to get yours ears (read brain) trained to all shades (read "shruti" to use a technical term) of the melody, it takes several decades. I have experienced this in my life. But again, this has no relevance to the subject here.

Regarding your subquestion on the timbre of sound: This is precisely what I called "spectrum" in my previous mail. As I said there and also in my previous longer mail, each sound consists of a wave packet (which is a superposition of a fundamental frequency and several harmonics of it). The relative presence of the frequencies determine the tibre (also called "quality" of sound, technically) which I have described as the spectrum of the sound. I have also indicated in both earlier posts and at least a couple of times elsewhere in this forum that passage of such a signal through a medium actually involves changing of that spectrum and hence the timbre of the sound, even if it's a subtle change. In a break-in , if it at all happens in your system, you would notice change in the frequency extremes the most significant. Unfortnately, to answer your question, I have never seen a measurement addressing this change. I believe it's one of the predominant change (as Venkat also noticed the second day in Bombay when his friend Arun's voice sounded exactly as Venkat knew) that happens with change of cabling, and among other things also in an equipment break-in in general (because of the capacitors?). This is precisely what I have been complaining about in my previous posts. Now that you yourself has understood that, please go back to the relevant portions of my previous 2 posts.

Sorry for using perhaps a slightly more inaccessible language in my previous mails. But you are certainly in the right track, according to me.

Regards.

 

[odyssey]

It seems that all of you (incl me) agree that speaker break-in does make a difference to the sound. Even this topic is contested by some including well known speaker designers. Alan Shaw of Harbeth is one such example. In fact, he has promised to eat a Harbeth speaker if anyone can prove that such changes exist. As for amplifier burn-in, I believe that I have experienced it many times, our customers have too. I have no proof per se in terms of measurements. On some amps the changes have taken time (e.g Odyssey) and on some amps the change has hardly been noticeable (e.g. Operetta). In terms of passive components anyone with experience of a TVC or a passive attenuator can probably also vouch to hearing differences....I would be curious to know anyone else's opinion on the latter two...

cheers

 

[Asit]

Alan Shaw of Harbeth is one such example. In fact, he has promised to eat a Harbeth speaker if anyone can prove that such changes exist.

Justing eating his words would be enough, IMO .

PS: I must say AS is one of the designer-manufacturers who interacts with his customers on a regular basis in the Harbeth forum. I have read his comments quite extensively and am quite fond of them. Could it be that Harbeths really do not break in? Is there any Harbeth owners among us? Are they available in India?

 

[odyssey]

They arent available in India. I have talked to only one Harbeth owner about break-in and he told me it was too long back that he doesnt remember. If I have this discussion with the other Harbeth owners I know, I will report here.

cheers

 

[venkatcr]

At least i don't know of anything where burn in was measured objectively. So experts, please throw some light on this aspect.: objective measurements for breaking in an amplifier

Jaudere:

This is where the great divide exists. Objectively you can measure a number of things such as voltage, current, wattage, resistance, sound wave forms, frequency, attenuation, insulation, linearity, heat, DC Offset, CMRR, RIAA, transients, etc. But how do you measure 'warmth', 'dynamism', 'digital sound', and so many similar subjective words that we throw around. Even if one understand these terms, it is well nigh impossible for two people to agree that what they are hearing or understanding what they hear is the same.

There is no right or wrong here. Just what you believe in. I strongly believe that a company like Bryston or FM Acoustics would ensure that all the objective tests are conducted and meet their standards. It is not possible for them to provide a 10 year warranty otherwise.

Cheers

 

[thevortex]

A top drawer discussion. Yet another one I am late on catching up to. But better late than never.

Personally speaking, I have experienced the effects of amplifier warm-up many times over. My Marantz as well as NAD amps sound much better after, say, 30 to 45 minutes of being switched on.

However on the subject of the amplifiers themselves breaking in - I have not been able to observe. This is because when I bought both these amplifiers anew I had them paired to new speakers! And I do believe in speaker break-in. So, if there was time for the amplifier to burn-in I would not know.

I guess, like so many other things in audio, this is another question for which there can be and probably only is a personal answer. I thought Cranky put it nicely when he said that either way there is truth. Only that it is a personal truth. I can go with that

 

[cha_indian]

I think it is all in the mind. If you believe that your amp can/will sound good after burn-in then it 'does' sound good.

What i have noticed is that there is nothing called burn-in. To me music sounds just the way it was new, anytime!!

 

[thevortex]

I am just reading this - pardon me for the belated response.

Venkat - cars and bikes absolutely do require break-in. I am not sure what you mean by 'abusing' them as soon as you drive them off the showroom. There are various break-in techniques recommended and you can look a lot of them up on the internet.

Simply put there are imperfections present in the piston and cylinder combination in the case of every vehicle. The process of breaking in is just about evening out those imperfections.

You can ride hard and break them in or you can ride sedately and break them in. Your mandatory oil change very soon after you take delivery of the vehicle is also done so that these particles which collect with the oil are taken out of the system as soon as possible. Your next oil change will take time.

This is not an argument for amplifier break in though. I am with you about the ears "requiring break in". However I am absolutely sure about the warm up period required whether it is tube or solid state amplification.

 

[venkatcr]

Venkat - cars and bikes absolutely do require break-in. I am not sure what you mean by 'abusing' them as soon as you drive them off the showroom. There are various break-in techniques recommended and you can look a lot of them up on the internet.

Bala, this is a very old post. Anyhow what I meant was this. In the days of Ambassador and Fiats, you had a governor that restricted that you drive at not more than 40KMPH (or some such speed) for some time decided by the manufacturer.

You can take a modern car and hit 140KMPH or whatever it is capable of as soon as you drive it off the showroom. That is what I meant by 'abuse'.

Cheers

 

[thevortex]

Bala, this is a very old post. Anyhow what I meant was this. In the days of Ambassador and Fiats, you had a governor that restricted that you drive at not more than 40KMPH (or some such speed) for some time decided by the manufacturer.

You can take a modern car and hot 140KMPH or whatever it is capable of as soon as you dive it off the showroom. That is what I meant by 'abuse'.

Cheers

Even today that dictat stands as per the manufacturer . That was my point. However in my opinion the 40 kmph mandate is invalid and has no basis. I would much rather worry about keeping my rev range within the meat of the torque curve.

 

[suri]

hi thevortex -

that (keeping the revs within the meat of the torque available) is going to be terribly difficult with the new (to be released) BMW 330i - going on a test-drive on 27th and whoops! - i will really flog the car!:clapping:

will definitely bounce the rev needle on cut-out with every gear till third! (the {stupid} civic bounces off at 6200 rpm} - the OHC vtec is much better )

 

[santhosh]

Even today that dictat stands as per the manufacturer . That was my point. However in my opinion the 40 kmph mandate is invalid and has no basis. I would much rather worry about keeping my rev range within the meat of the torque curve.

You are right Bala, it is the RPM that matters more than speed in kmph. But back in those (Ambassador and Fiat) days, automobiles did not come with a Tacho meter and the speed was used as an approximate guide. Infact, even Maruti used to recommend shifting to 5th gear only after 40kmph because of the lack of a Speedo.

Since we are on the topic of breaking in of automobiles, this trick works out well for me if it is a new car:
Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

hi thevortex -

that (keeping the revs within the meat of the torque available) is going to be terribly difficult with the new (to be released) BMW 330i - going on a test-drive on 27th and whoops! - i will really flog the car!:clapping:

Wow Suri, have fun:clapping:!! The Good old VTEC rocks!!

 

[venkatcr]

Due to the vastly improved metal casting and machining technologies which are now used, tight parts in new engines are not normal. A manufacturing mistake causing a tight clearance is an extremely rare occurrence these days. But, if there is something wrong with the engine clearances from the factory, no amount of gentle running will fix the problem.

Should I gloat and say I told you so?

Cheers

 

[Hari Iyer]

Do Components values in amplifiers (active and passive) used in the circuitry change with time? Most of the resistors used are 5% tolerance and most capacitors are usually commercial grade and not military grade. Does that mean the specifications quoted for the amplifiers in the manuals change over time due to variation of their values? Any answers?