Crites Q&A on capacitors, burn-in, etc. ---- discuss among yourselves

[bmwr75]

http://www.critesspeakers.com/frequently-asked-questions.html

Keep in mind Bob Crites is a speaker guy.  Don't think what he says can automatically be extrapolated to electrical components used in amps, etc.

[OldiesButGoodies]

I agree with most of what he lays out here.  Anders - which of his statements do you disagree with and why? Let's take capacitor break in.  He believes it is not real.   You disagree.  Why?

[rgpit]

Regarding burn in, I believe that there may be audible effects as the capacitor's dielectric material changes over time from being exposed to the electric field applied to the capacitor plates. I understand many will say there is no audible difference but there is a mechanism for change.

[rgpit]

Another aspect that differentiates caps is microphonics.

Depending on the way a capacitor is manufactured and how tightly it is wrapped it can become slightly microphonic. Think about the varying pressures that a cap is exposed to inside of a speaker enclosure.

[Anders]

I say it because I hear it everytime !

[Anders]

rgpit is correct.
There are scientific reasons for the differences.
Just because you can't hear a difference that doesn't mean no one else can. You may just need to learn to hear the difference.

[scorpio333]

There was a thread awhile back about caps, it was suggested 200hrs and they'd be broken in. So I recapped a set of speakers. They immediately sounded different. However, since then they sound the same to me as they did after the recap. Is it possible the change is so subtle in that 1st 200hrs that it's impossible for the "unlearned ear" to hear it? I don't think my ears are sensitive enough or my memory strong enough to remember the sound differences.

[OldiesButGoodies]

We can probably all agree that expectation bias could make us believe there are changes?  (or a small change may be amplified by it?)

Expectation bias:  the tendency for experimenters to believe, certify, and publish data that agree with their expectations for the outcome of an experiment, and to disbelieve, discard, or downgrade the corresponding weightings for data that appear to conflict with those expectations.

Crites point - If we can measure the characteristics of a cap as capacitance and ESR, and both are within spec when new,  what changed to make them sound different 200 hours later? And did the change move them out-of-spec?  Anders - if your hearing os correct, and the capacitance and ESR remain the same,  something else measurable and related to sound must have changed.  What do you think that would be? Microphonics would strike me as making caps sound worse as it increases. 

[schwarcw]

I am curious about inductors which are also part of the speaker's crossover circuit.  If similar value inductors (mH, ESR or whatever) what difference air core vs solid core or other types?  Burn in is an interesting and controversial subject for any component.  I know that I have heard audible changes after performing a crossover upgrade.  I don't profess to be an expert on critical listening but professional recording engineers are trained in critical listening. 

[rgpit]

The microphonics reference was not to related to burn in. Just brought it up to show there are aspects to caps that aren't always spec'd out. There's more to it than just the initial capacitance, breakdown voltage' and ESR.

Here is a link to the Wima capacitor technical site. Lots of good info.        http://www.wima.com/EN/technicalinformation.htm

Quote from their website regarding film cap stability .. "Environmental influences such as heat, high humidity and strong mechanical vibrations can, over a longer period of time, due to ageing, lead to an irreversible change in the capacitance value." *This tells me that it is possible for changes to occur during usage (i.e. burn-in)

[rgpit]

Carl

There are a lot of mechanical forces generated when the electromagnetic field changes in a coil which is why a speaker cone moves, a motor turns, or a solenoid actuates. I would think that in a given inductor, if the windings are not solidly wound and can vibrate due to magnetic fields or just mechanical resonance there could be audible artifacts.

Also ferrite and iron cores will saturate when the field strength is too high from applying high currents. The benefit of using cores other than air is that you can achieve higher inductances with less wire which also yields a lower DCR.

[Anders]

Take a look at this and tell me all caps sound the same.
http://www.humblehomemadehifi.com/Cap.html

[Anders]

I reject expectation bias and I keep an open mind and open ears.

[Sir Thrift-a-Lot]

Here is a link to the Wima capacitor technical site. Lots of good info.        http://www.wima.com/EN/technicalinformation.htm

Quote from their website regarding film cap stability .. "Environmental influences such as heat, high humidity and strong mechanical vibrations can, over a longer period of time, due to ageing, lead to an irreversible change in the capacitance value." *This tells me that it is possible for changes to occur during usage (i.e. burn-in)

A change in value is easily measured, though.

[Sir Thrift-a-Lot]

Take a look at this and tell me all caps sound the same.
http://www.humblehomemadehifi.com/Cap.html

I missed where anyone said that all caps sound the same.