I apologoze if this has been asked before but I searched and did not find discussion about this.
I have been using Wima MKP10 on a couple of tube preamps that I built. I can tell those caps need some time to burn in to sound good.
One of my preamps was sitting in the shelf for a while and I just pulled it out and use it again. I thought the WIMA inside was already burned in but the sound at first was really dry and grainy like brand new WIMA. I let it played for a while (probably 2 hours) and the familiar sound begin to come back.
So, if a WIMA (or generally a film cap) has been burned in but then sitting for a while, a re-burn in period is needed ?
I have been using Wima MKP10 on a couple of tube preamps that I built. I can tell those caps need some time to burn in to sound good.
One of my preamps was sitting in the shelf for a while and I just pulled it out and use it again. I thought the WIMA inside was already burned in but the sound at first was really dry and grainy like brand new WIMA. I let it played for a while (probably 2 hours) and the familiar sound begin to come back.
So, if a WIMA (or generally a film cap) has been burned in but then sitting for a while, a re-burn in period is needed ?
I thank you for that honest posting.
This "craze" or "myth" about burning in parts is purely driven by internet blabbering, and there's no real proof to back it up.
Because as you say, the listener "perceives" a change by way of adapting to a particular sonic signature.
Hopefully, people will read and take note of this, and stop inventing "nothings" to make others crazy.
Honestly, I was a little hesitated to post due to the fact that this topic has always been argued upon. And I risk putting myself at the center of the target being shot at (which had)....
So, in this case, I built two identical tube preamps. One has been used daily and the other was in storage for months. Therefore, I'm familiar with the sound characteristic of them. I observed the one in storage sounded dry after not being used for months. Then after two hours of playing, the familiar sound has come back. The other identical amp, which has been used daily, does not exhibit this issue.
I once questioned myself if this is an adaptation or myth or something along this line (your comments). But I do observe (more than once) the sound does change when a cap has more time in service.
(I cannot find a way to remove my own thread)
So, in this case, I built two identical tube preamps. One has been used daily and the other was in storage for months. Therefore, I'm familiar with the sound characteristic of them. I observed the one in storage sounded dry after not being used for months. Then after two hours of playing, the familiar sound has come back. The other identical amp, which has been used daily, does not exhibit this issue.
I once questioned myself if this is an adaptation or myth or something along this line (your comments). But I do observe (more than once) the sound does change when a cap has more time in service.
(I cannot find a way to remove my own thread)
It was not the Wima needed re-burn in but the whole preamp. The differences could be dramatic if the preamp was left unused for many months. The sound then will come back after days, not hours, of playing.
Observed this for many machines. Once I declared a friend's preamp from a well known brand, inferior, not worth even a fraction of the money of my diy one, only to be proven wrong some hours before I've given it back. And that was the 4th or 5th day.
I have a friend which I know he doesn't spend much time listening, every time I get something from him I have to spend a considering amount of time burn-in the machine, not just a day or two.
Wima MKP10 need some time to settle in but not that much, not more than 100-150 hours. And it doesn't show it's true character from day one and then improves as the burn-in goes. Nope, it's a different beast at first so you must be patient and not do critical listening right away.
Observed this for many machines. Once I declared a friend's preamp from a well known brand, inferior, not worth even a fraction of the money of my diy one, only to be proven wrong some hours before I've given it back. And that was the 4th or 5th day.
I have a friend which I know he doesn't spend much time listening, every time I get something from him I have to spend a considering amount of time burn-in the machine, not just a day or two.
Wima MKP10 need some time to settle in but not that much, not more than 100-150 hours. And it doesn't show it's true character from day one and then improves as the burn-in goes. Nope, it's a different beast at first so you must be patient and not do critical listening right away.
I'd say it's pretty silly to think that the molecular electronic properties wouldn't change with stress from electromotive force (AKA being powered up). There are many different types of capacitor because none is perfect and nearly all (if not all) have properties that are affected by the environment they are operated in and by age.
As a consequence capacitors certainly do have 'sound', the boundary conditions inside capacitors do change over time as a function of the voltage and current through them (both DC quiescent and AC components) and there is established and accepted physics at play, though not every aspect of change in electro-molecular properties is documented or understood as yet.
Still I'm interested in whether the change you perceive is the capacitors or some other effect in other components in the preamplifier.
Cyril Bateman is a respected capacitor designer and has published a number of papers on the implications of different materials used in capacitor manufacture and time dependent properties that affect sound. He has conducted tests on some WIMA capacitors, but I'm not sure if that includes the MPK10 family.
Cyril Bateman's Capacitor Sound articles | Linear Audio NL
As a consequence capacitors certainly do have 'sound', the boundary conditions inside capacitors do change over time as a function of the voltage and current through them (both DC quiescent and AC components) and there is established and accepted physics at play, though not every aspect of change in electro-molecular properties is documented or understood as yet.
Still I'm interested in whether the change you perceive is the capacitors or some other effect in other components in the preamplifier.
Cyril Bateman is a respected capacitor designer and has published a number of papers on the implications of different materials used in capacitor manufacture and time dependent properties that affect sound. He has conducted tests on some WIMA capacitors, but I'm not sure if that includes the MPK10 family.
Cyril Bateman's Capacitor Sound articles | Linear Audio NL
Definitely more of a materials/physics domain than that of a textbook electrical thing, not something that all can appreciate.
The process of establishing new parts is always somewhat predictable yet never the same in all situations…
I only have the mkp10 in one amp, as input filtering, but have not used it enough to experience what you’re describing.
The process of establishing new parts is always somewhat predictable yet never the same in all situations…
I only have the mkp10 in one amp, as input filtering, but have not used it enough to experience what you’re describing.
Because of the way they are manufactured un-impregnated capacitors inevitably contain distributed minute pockets of air, trapped inside the windings. The oxygen in the entrapped gas provides a mechanism for change in performance over time. Bias voltage across the capacitor may affect or reverse the boundary layer changes thus caused.
Most likely the tubes themselves have esablished certain parameters once they become good and hot.
You are trying to cook a non explanation for a non fact.
If anything even remotely similar happened, it would be measurable and capacitor datasheets would show it, including some graphs, as in Capacitance vs Time change.
But they don´t.
Meanwhile I´ll file the oxygen microbubbles explanation together with the microdiodes one, the Quantum Physics "explanation" about sound "granularity" , the "black noise" one, the influence of Gravity on Audio Waves and a few others.
If anything even remotely similar happened, it would be measurable and capacitor datasheets would show it, including some graphs, as in Capacitance vs Time change.
But they don´t.
Meanwhile I´ll file the oxygen microbubbles explanation together with the microdiodes one, the Quantum Physics "explanation" about sound "granularity" , the "black noise" one, the influence of Gravity on Audio Waves and a few others.
Thank you for mentioning this. Tubes change all the time, and eventually become "not tubes" when they wear out. Of course it's reasonable to suspect that the tubes are changing as they are powered up. The mere act of powering a tube up (applying plate voltage with a cold cathode) can strip the emissive metal layer from the cathode where it is then re-grown from the oxides on the cathode over a smallish period of time... perhaps hours.
Polypropylene film caps also have a significant temperature coefficient, so they will physically warm up and change value after two hours of heating. I would not call that "burning in" but simply "warmup".
Finally, there are a ton of components in that device, including your wall AC voltage, that, depending on the circuit, could change things over time or with different times of day, Ascribing the changes only to a polymer film cap is not logically warranted - it's just your own focus.
Polypropylene are for practical purposes perfect for audio, its electrolytics you might have to worry about.
There is no burn-in for film caps, the closest you get to this is dilectric absorption which is a fast process, and dielectric absorption is generally higher is lower-performing dielectrics.
Read Cyril Bateman's article johnmath cited - highly recommended.
You also should read about expectation bias and why double-blind testing is absolutely essential for judging audio equipment by ear - anything else gives meaningless results.
There is no burn-in for film caps, the closest you get to this is dilectric absorption which is a fast process, and dielectric absorption is generally higher is lower-performing dielectrics.
Read Cyril Bateman's article johnmath cited - highly recommended.
You also should read about expectation bias and why double-blind testing is absolutely essential for judging audio equipment by ear - anything else gives meaningless results.
I have spent hundreds, perhaps thousands, of hours in blind testing audio components over many decades. It's not often realised that expectation bias works both ways. Without confirmation from blind testing is just as easy to not hear something you don't expect, as it is to hear something you do expect.
The elephant in the room is that some people simply hear more detail than others, not because they have better brains or ears, but because of experience and interest whether deliberate or accidental. Just like appreciating fine wine, appreciating fine audio depends on knowledge, interest and experience, and it helps to have a language to express impressions in an unambiguous way. Luckily for hifi enthusiasts, these characteristics tend to get better with age, despite the fact their auditory mechanism is actually become less adroit.
Your quoting the wrong person, but I do find it interesting that these nuances get more common with what must be worse hearing.
There is nothing significant measurable electronically or acoustically with a decent plastic capaciitor "burning in" so I am inclined to suspect that nothing is happening. Plenty of other things do change, especially the speakers in the room and also the listener. It is a feature of our biology that if you over stimulate a nerve, it loses sensitivity
There is nothing significant measurable electronically or acoustically with a decent plastic capaciitor "burning in" so I am inclined to suspect that nothing is happening. Plenty of other things do change, especially the speakers in the room and also the listener. It is a feature of our biology that if you over stimulate a nerve, it loses sensitivity
After extended periods of inactivity all caps require some time until their sound settles down again. And so does wire and solder joints. And lots of other parts. It is basic empiric knowledge for everyone possessing a pair of ears and having good sound as a hobby.