Capacitor Burn-In/Break-In

[marce]

AndrR
pre-prepared responce, as I didn't say I didnn't believe, I asked questions, and for the record I dont believe in anything, life is but an illusion, here the reply:
If I am to learn anything, then why can I not question. Anecdotal information is of no use to me, I would like empirical data so that I can understand what is causing the change, and what effect electrically are taking place. This data can be collated with other experimental data and I can make a decision based on facts. That is what engineering is, and audio reproduction is engineering based, when I am trying to improve my system I am not creating some art work or musical instrument, I am building or re-engineering a tool, that's function is to reproduce music with the maximum fidelity, only by a combination of measurements and listening can an engineering decision be formed, and only with hard empirical data can you reproduce and determine how the change is made and what path to improve it more (if a change does in fact make an improvement).

[marce]

Further if the tweeter sounds to bright I would not expect some minor change to smooth things.
Simon7000, I guess this trick if for plastic film based caps?

[simon7000]

Originally Posted by marce

Further if the tweeter sounds to bright I would not expect some minor change to smooth things.
Simon7000, I guess this trick if for plastic film based caps?

Any plastic or non hermetic capacitor will be affected by moisture content. This decreases from use. As water is slightly polar there is voltage induced movement of the molecules. This may show up as an increase in distortion peaking at some frequency that could be influenced by film type and thickness. As the capacitor is used or even placed in a warm environment the humidity level in the film drops.

[SY]

Depends on the plastic. Mylar will pick up a few tenths of a percent (I think this was what Doug Self was seeing in his Linear Audio article). Polyprop, polystyrene, PTFE, as close to zero as you could want.

[simon7000]

Originally Posted by SY

Depends on the plastic. Mylar will pick up a few tenths of a percent (I think this was what Doug Self was seeing in his Linear Audio article). Polyprop, polystyrene, PTFE, as close to zero as you could want.

I haven't tried all of the types you mention. I think we agree the mylar has that problem. But I have also seen to a lesser extent the issue in polyprop. I don't know if it had to do with winding gaps or resin used. It was an "Audio" cap so quality of winding could be the reason for moisture issues.

Polystyrene and teflon are considered the golden boys of caps and are well known as very stable designs. But there is a cheap brand of polystyrene caps that do not seem to perform as well as others. As they even have a bit of different optical quality from the better ones I suspect either regrind or just a lower quality of resin.

Then there is always the issue of corrosion at the connections in extreme cases of moisture exposure, although I haven't seen that in any in use capacitors.

[SY]

Originally Posted by simon7000

But I have also seen to a lesser extent the issue in polyprop. I don't know if it had to do with winding gaps or resin used. It was an "Audio" cap so quality of winding could be the reason for moisture issues.

Far more likely that than the film- an example of why I avoid "audiophile" caps.

[marce]

When I get some 'first off' plastic parts (ABS, PC generally), the moulders put them in a sealed bag with a drop of water for 24 hrs, this improves the materials properties by a small amount...I was surprised when I first learnt this as I would not have imagined that plastics can absorb water.
As I dont use audiophile caps, just standard available caps from Farnell etc I dont supose I'll worry about any humidity caused changes.

[jacco vermeulen]

This is where a boat guy would mention to read up on Adolf Fick.

(epoxy resin sealing rules the galaxy, but i rather stick to aluminum if you don't mind )

[umut1001]

I think old electrolytic capacitors become better (less then 50-63volts)after using some ten hours so the people who does not know about "reforming caps" thinks that it is burning in.So it became a trend

[TV7]

Originally Posted by serengetiplains

I changed the rectifier bridge from the old, heavy workhorse (circa. 1985) to a new, sprite FRED module. No change in the spike. I also swapped out the three circuit boards, exchanging them with those in my other Elgar, and no change.

That leaves: the wiring, the two banks of output transistors, and the transformer.

And the capacitors.

Here's today's visual.

Magnetic saturation of the transformers of course! shifts in the magnetic pole, American High Frequency Active Aural Research Project! HAARP , little green men!

Actually nutty suggestions aside I also notice chances in audio output of coupling caps after running for some time. To my ears they smoothen out. I just did the .47 coupling in my C22 preamp with some NOS sprague black beauties and my initial impression was WHAT HAVE I DONE!! when given a few hours run in they sound just lovely. My opinion only, after observation of course.