Interesting thread.
Where there's smoke, there's fire.
The problem/effect is genuine!
It's a result of the vast majority of power amplifiers having sufficiently poor PSRR at some point in the audio spectrum that the listener is hearing the harshness of power supply artefacts ( for example from the supply impedance highlighted half-wave Class AB commutation).
Supply C ESZ and particularly ESR is a prime source of supply impedance and this drops at elevated temperature. So less imposed 'spray' of harmonics on the supplies as the C warms up. So 'burn in' warms these up, drops the ESR and it's 'sweet' music!
Electrocompaniet, I believe knew this with their closed up 'cooking' chassis generated by high bias. The supply C's were running at elevated temps. ESR dropped - less PSR artefacts.
No doubt there's a memory effect as with most things. So it lives!
Trouble is that electro's lifetime is inversely proportional to temp so you can enjoy this effect only for a short time, because long before these C's fall over (i.e. be physically exhausted, they will suffer sonically with soft bass. 10 times or as little as 400 hours is a guide). This is why I design high PSRR amps so you're not listening to the power supply in the first place, and run them 'nude' to aid dissipation od internal heating. Multipler C's with their associated distributed heat centres are a plus, at least for constancy and lifetime.
My take.
Cheers,
Greg
Where there's smoke, there's fire.
The problem/effect is genuine!
It's a result of the vast majority of power amplifiers having sufficiently poor PSRR at some point in the audio spectrum that the listener is hearing the harshness of power supply artefacts ( for example from the supply impedance highlighted half-wave Class AB commutation).
Supply C ESZ and particularly ESR is a prime source of supply impedance and this drops at elevated temperature. So less imposed 'spray' of harmonics on the supplies as the C warms up. So 'burn in' warms these up, drops the ESR and it's 'sweet' music!
Electrocompaniet, I believe knew this with their closed up 'cooking' chassis generated by high bias. The supply C's were running at elevated temps. ESR dropped - less PSR artefacts.
No doubt there's a memory effect as with most things. So it lives!
Trouble is that electro's lifetime is inversely proportional to temp so you can enjoy this effect only for a short time, because long before these C's fall over (i.e. be physically exhausted, they will suffer sonically with soft bass. 10 times or as little as 400 hours is a guide). This is why I design high PSRR amps so you're not listening to the power supply in the first place, and run them 'nude' to aid dissipation od internal heating. Multipler C's with their associated distributed heat centres are a plus, at least for constancy and lifetime.
My take.
Cheers,
Greg
A lot of the content posted is very interesting and obviously subject to heated debate, but lets look at the original request.
If people do subscribe to "power amplifier burn in" then they should suggest the right method and why it has a beneficial affect.
I.e. by using 100khz anti-phase triangular signals of 10v peak to peak the electrolyte will align to the correct polarity (groan) and polarise the sound stage to the correct alignment (it hurts) ...but hey even I can do this....(could be my first trip to Texas).
Cheers anyway.
beppe61 said:
If people do subscribe to "power amplifier burn in" then they should suggest the right method and why it has a beneficial affect.
I.e. by using 100khz anti-phase triangular signals of 10v peak to peak the electrolyte will align to the correct polarity (groan) and polarise the sound stage to the correct alignment (it hurts) ...but hey even I can do this....(could be my first trip to Texas).
Cheers anyway.
Dear Friends,
I seem to remember a web page (do not remember anyway the link) where the author wrote about a "forming" phenomena for NEW ELECTROLYTIC CAPS when they are put under tension and they go through some charging and discharging cycles.
Maybe is just "fried air" (as we say in Italy).
I really do not know.
Kind regards,
beppe61
I seem to remember a web page (do not remember anyway the link) where the author wrote about a "forming" phenomena for NEW ELECTROLYTIC CAPS when they are put under tension and they go through some charging and discharging cycles.
Maybe is just "fried air" (as we say in Italy).
I really do not know.
Kind regards,
beppe61
janneman said:
Dear Mr. Didden,
thank you so much for the extremely interesting link.
So electrolytics go through some sort of "chemi-physical change" caused by the flowing of current trough them.
And for this their behaviour change with time of functioning.
It is just a rambling maybe.
Thank you very much again.
Kind regards,
beppe61
amplifierguru said:
Dear Mr. Greg,
thank you very much indeed for your extremely kind and interesting opinion.
If I understand well you mean that at the end is always and just a matter of noise from the supply, made worse by amps with bad PSRR.
If it is like that, you have convinced me.
By the way, great projects yours. I will study them accurately.
Thank you very much again.
Kind regards,
beppe61
janneman said:
Dear Mr. Didden,
thank you very much for your extremely interesting precisation.
It makes a very lot of sense to me.
So new caps "need" burn-in, something like a sort of "activation", before being fully functional.
This could explain for instance the effects experienced by Mr. Carlos Filipe in the listening to his Guido Tent clock (that I think was brand new and with electrolytics inside).
Thank you very much indeed.
Kind regards,
beppe61
beppe61 said:
'Could explain' is not the same as 'explains it'. That is the lack of logical thinking here.
Fact: components change with temperature.
Therefore: the sound chnages with temperature - no!
Engineers go to great length to build equipment that is immune to temp change, aging, spread in component values, etcetera. Countless engineering hours are spend precisely to AVOID this stuff. Yet, anybody seems to feel qualified to state: hey, there's a temp delta that must explain the sound difference.
There may be a perception difference. Well established phenomena. Nothing to do with the actual sound.
Jan Didden
janneman said:
Dear Mr. Didden,
if I speak of "forming" instead of "burn-in" can I get your agreement (eh, eh, eh) ?
No seriously.
I have these "brand new" electrolytic caps and I "do" experience a change in the sound with time.
And I think it is not only driven by a rise of the temperature of caps.
This generated my question about the burn-in.
I can fully agree that after some time there will be some kind of "stabilization" of the caps properties and therefore of the sound.
I do not negate this.
So we think the same.
Thank you very much again.
Kind regards,
beppe61
P.S. If I use often could it is because I'm not sure at all and I hope that someone kindly clear my mind.
janneman said:
No, it's not!
Too many people get fooled by the looks, and those are the ones that buy that gear because it's bijou, or that car because it's pretty.
Where's the knowledge here, where's the real test?
I'm more like 'ok, that looks very nice, but let's hear it'.
What if a Pioneer A400 beats a Krell KAV-300iL side to side, does it shock you?
It doesn't shock me!
But the Krell looks cool, and people like to own something with 'status'.
But this is all bull**** to me, if it doesn't sound good, it's not for me.
Open your mind, man, I've heard a cheap Panasonic class-D amp beating a $$$ Jadis tube amp easily.
But the Jadis made a good candle!
Jan, seriously, getting fooled by the looks is a very beginner's mistake to make.
janneman said:
Nothing 'explains it' to you, as your 'well established phenomena' doesn't explain it to me, so it's useless.
The effect I described with the Tent clock is unrepleatable, it only happens at first power on, when new.
You can leave the player disconnected for months, and you will never hear such a nasty presentation again.
But Jan, I know this is just exercising my fingers typing this, because for you everything is imagination.
I'm not posting for you exclusively, anyway, and many other people will recognize what I'm saying and agree.
'I didn't hear any difference' -> just means that YOU didn't hear any difference.
'Lots of people on a DBT didn't hear any difference' -> just means that they couldn't hear any difference.
'The white paper says there is no difference' -> is it to be taken religiously???!
'I didn't meansure any difference' -> just means that you couldn't measure any difference. Doesn't mean that there is no difference!
Proofs?
What proofs?
what established phenomena?
Hey, it was an established phenomenta that the Earth was flat, and it was the center of the universe.
Go figure...
carlosfm said:
No, it's not!
Too many people get fooled by the looks, and those are the ones that buy that gear because it's bijou, or that car because it's pretty.
Where's the knowledge here, where's the real test?
I'm more like 'ok, that looks very nice, but let's hear it'.
What if a Pioneer A400 beats a Krell KAV-300iL side to side, does it shock you?
It doesn't shock me!
But the Krell looks cool, and people like to own something with 'status'.
But this is all bull**** to me, if it doesn't sound good, it's not for me.
Open your mind, man, I've heard a cheap Panasonic class-D amp beating a $$$ Jadis tube amp easily.
But the Jadis made a good candle!
Jan, seriously, getting fooled by the looks is a very beginner's mistake to make.
Nothing 'explains it' to you, as your 'well established phenomena' doesn't explain it to me, so it's useless.
The effect I described with the Tent clock is unrepleatable, it only happens at first power on, when new.
You can leave the player disconnected for months, and you will never hear such a nasty presentation again.
But Jan, I know this is just exercising my fingers typing this, because for you everything is imagination.
I'm not posting for you exclusively, anyway, and many other people will recognize what I'm saying and agree.
'I didn't hear any difference' -> just means that YOU didn't hear any difference.
'Lots of people on a DBT didn't hear any difference' -> just means that they couldn't hear any difference.
'The white paper says there is no difference' -> is it to be taken religiously???!
'I didn't meansure any difference' -> just means that you couldn't measure any difference. Doesn't mean that there is no difference!
Proofs?
What proofs?
what established phenomena?
Hey, it was an established phenomenta that the Earth was flat, and it was the center of the universe.
Go figure...
Carlos, relax. I didn't say I didn't hear it. I said the 'burn-in' effect DOES exist, only it is not because of the change in sound.
Jan Didden
Dear Mr. Carlos,
thank you very much indeed for your extremely interesting disclosing of your valuable experiences.
I have to tell you that I find very very interesting your comments about the effect of PS on clocks from different manufacturers.
I am a digital addict so any discussion on clocks switch my brain on. A good digital source needs always a very steady clock.
That said, let me put you some questions between the lines.
>
thank you very much indeed for your extremely interesting disclosing of your valuable experiences.
I have to tell you that I find very very interesting your comments about the effect of PS on clocks from different manufacturers.
I am a digital addict so any discussion on clocks switch my brain on. A good digital source needs always a very steady clock.
That said, let me put you some questions between the lines.
>
Originally posted by carlosfm
No, it's not!
Too many people get fooled by the looks, and those are the ones that buy that gear because it's bijou, or that car because it's pretty.
Where's the knowledge here, where's the real test?
I'm more like 'ok, that looks very nice, but let's hear it'.
Very very true. I have friends that judge equipments on cosmetics. They want primarly a nice piece of furniture.
> What if a Pioneer A400 beats a Krell KAV-300iL side to side, does it shock you? It doesn't shock me!
It shock me as well, because I think to the price differential.
Excuse me, it is just an example or does this reflects your opinion?
I understand, if I am not wrong, that the A400 has a single power supply and is capacitor-coupled at the output.
So this cap should be not detrimental for good sound.
I am very interested in this topic of capacitor coupled amps.
> But the Krell looks cool, and people like to own something with 'status'. But this is all bull**** to me, if it doesn't sound good, it's not for me.
We are at least in two thinking the same then.
> Open your mind, man, I've heard a cheap Panasonic class-D amp beating a $$$ Jadis tube amp easily.
But the Jadis made a good candle!
Interesting. Which model?
Thank you very much for your excellent posts.
Personally I believe in your hears.
Yours sincerely,
beppe61
beppe61 said:
There you have it. You may not give much importance to looks, but you are still biased by the price differential, and that fact makes you go into previous assumptions that can prove wrong when you really listen.
beppe61 said:
It's an example and it's also my oppinion/conclusion.
I had both at home at the same time and for some weeks, compared them in my main system.
beppe61 said:
No, absolutely not, the Pioneer has dual PSU, and no cap on the output.
It has a much more direct signal path, a simple discrete preamp, and much less junk in the signal path than the Krell (which has multiple electrolythic DC coupling caps, discrete input stage, and two stages of op-amp buffers and gain).
Clearly, the simpler and more careful (IMO) design of the 'old' Pioneer just ends in a result that is what really matters: it sounds better.
On the Krell you are paying for an incompetent design (IMO), excessive, detrimental, unnecessary stages, the 'Krell' words on the front, and a "made in USA" badge on the back.
EDIT: btw if you don't know, the Pioneer A400 was a very raved amp 15 years ago. It was designed by Pioneer UK.
No tone controls, no balance, no loudness, just careful layout and direct signal path, simple and effective.
beppe61 said:> Open your mind, man, I've heard a cheap Panasonic class-D amp beating a $$$ Jadis tube amp easily.
But the Jadis made a good candle!
Interesting. Which model?
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.
carlosfm said:
Carlos, this is simply untrue! I know you hate it when I bring up other documentation, but the Harman piece is clear. Here we have experienced listeners, loudspeaker designers. They KNOW the problem. At the test start they SAY that they know the problem of influence of looks etc. They feel confident that they can filter it out because they KNOW what/how to listen. But they still fell for it! Like I said, it is in your genes!
Jan Didden
Dear Mr. Carlos,
thank you very much again for your very kind and extremely valuable reply.
Let me put some other very important (for me) questions to you.
>
Your opinion could be not exposed more clearly .
Thank you very much for the very interesting and valuable information.
Kind regards,
beppe61
thank you very much again for your very kind and extremely valuable reply.
Let me put some other very important (for me) questions to you.
>
Originally posted by carlosfm
There you have it. You may not give much importance to looks, but you are still biased by the price differential, and that fact makes you go into previous assumptions that can prove wrong when you really listen.
Perfectly clear.
> It's an example and it's also my oppinion/conclusion.
I had both at home at the same time and for some weeks, compared them in my main system.
No, absolutely not, the Pioneer has dual PSU, and no cap on the output.
It has a much more direct signal path, a simple discrete preamp, and much less junk in the signal path than the Krell (which has multiple electrolythic DC coupling caps, discrete input stage, and two stages of op-amp buffers and gain).
Very very interesting. Clearly I was very wrong.
I happen to like better simple designs.
That usually also sound better.
Dual PSU. I am beating myself to have lost an auction on ebay.it.
I will search for another one then.
> Clearly, the simpler and more careful (IMO) design of the 'old' Pioneer just ends in a result that is what really matters: it sounds better.
This is also very interesting.
Old designs better than newer ones. Very interesting.
A sign of "audio decadence"?
> On the Krell you are paying for an incompetent design (IMO), excessive, detrimental, unnecessary stages, the 'Krell' words on the front, and a "made in USA" badge on the back.
Your opinion could be not exposed more clearly .
Thank you very much for the very interesting and valuable information.
Kind regards,
beppe61
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