Removing Plastic covers from Capacitors

I don't belive this at all, in fact I think you will ruin the cap. Is it possible to remove the cover without damaging the cap? We have talked here about capacitor distorsion

http://www.diyaudio.com/forums/showthread.php?s=&threadid=5107

and come to the conclusion that the distortion is very small. It's better to take care of the circuit design instead.
 
Cap Mods

It is very easy to try and will not ruin the cap. You can run a soldering iron across the plastic and peel it right off. Mark the leads for polarity if you do this befor installing cap. I have heared differences from putting damping material on caps. "Maybe this is a little "extreme" for Peranders. It is pretty well accepted that caps sound different even among electrolytics.
 
Peranders,

If you would check my thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=5903, you would already know that proper combining of materials and structural support, are as important as circuits themselves. It is still only my opinions, but by doing a lot of experimentation in that field I'm more and more certain of that.;)

Depending what I placed under my CD-PRO transport I got completely different sound. Sometimes it sounded worse than cheap $100 player, sometimes it was high end sound.

I've also heard that removing plastic covers from electrolytics improves sonics. You got two different materials interacting with ea. other. When you remove one the vibrational properties change and possible change in sound signature could be observed.

I didn't try it yet (I'm using 120 electrolytics in my current amp) and I'm also very reluctant to remove that nice plastic from my 22,000 Cerafine caps.;)

But it can be easily done, just cut the plasic (but not completely, so as not to scratch aluminum) and pull it off. We would be curious to hear your obsevations.
 
On aluminum electrolytics at least, you can remove the plastic from the outside and gain a little better heat dissipation, and therefore a higher ripple current capability. I wouldn't try unwrapping the plastic on a film (polyester, polypropylene, etc) capacitor though, as I've seen some of them where the film on the outside is just a continuation of the dielectric, and if you unwrap it, you'll unwrap the whole capacitor.

Of course, this is unnecessary and won't make a difference unless you're really pushing the limits of the capacitors' ripple current capability.

(and it won't make them sound better - it'll just give them a little bit longer life, all other things being equal)
 
and it won't make them sound better

ThingyNess, take a Coke can and put some plastic around it, then compare the sound when you knock on it. Is it different?;)

I'll go even further: do you have a preferance for the sound of Coke can with a plastic or without it? Expect similar differences in sound for caps with plastic and without it. I'm not joking.;)
 
Re: referenceaudiomods.com

GIVE ME A BREAK!

In fact, recent reseach suggests that power amplifiers (and electrolytics) should be operated in sealed glass containers in which the air has been replaced with argon. Input and output connections are made via feedthrus. The temperature must be reduced to -100C over a period of 10 years.

We a currently running a $29.95 special on this process. This offer ends Oct 15, 2002 so send us your amps and a check today.
 
Peter,

Take an audio signal (say 5V pk-pk as it gives us a better S/N ratio for our test, high voltages being better) audio signal (your choice which kind, sines are nice as they're easy to analyze) and alternately pass it through two electrolytic capacitors (one with the plastic on, and one with the plastic off.)

Examine the output of each on a 'scope. Note any differences you see.

Now take a large screwdriver and smack each capacitor around a bit - on the top, bottom, sides, etc. Again, note any fluctuations or oddities in the 'scope readout. For more fun, use a digital 'scope and capture the waveform as you do this so you can examine it later for any transients you may miss on an analog scope.

Worrying about mechanical resonances is one thing when you're dealing with a device that's designed specifically for electrical -> mechanical energy conversion (IE, a loudspeaker), but a completely different thing when you're talking about mechanical resonances in a device designed to pass the signal electrically.

Of course, you can generalize this as much as you want - grab yourself a distortion analyzer, capture the output of the distortion analyzer with a 'scope, and during the test, take an 8 pound sledge and start beating the hell out of your favorite amp. It can be quite a fun test. :)

Considering the fact that moving my head the amount required to scratch my ear likely changes the frequency/phase response more than any esoteric tweak you could do to your system, I'm not about to go and worry about mechanical damping in my amplifiers anytime soon - spending 5 minutes tweaking the bracing/damping on your speakers will likely have more effect than a lifetime of rubber isolation mounts for your non-transducer audio gear.

Of course, many people love the subjective part of audio, and if you consider yourself a subjectivist, by all means, remove the plastic. While you're at it, you might want to slip a woven carbon fiber "sock" over the cap - I hear those sound much better than the inferior wool ones. :)

Besides, in a lot of psychological (and even physiological) tests, the placebo does almost as well as the real thing. The power of suggestion is a strong one indeed. ;)

(for what it's worth, I find most of the stuff you've posted here to be beautifully designed/constructed, Peter, and I wish I could make my DIY efforts look that good.)
 
Capacitors

Well you can lead a horse to water but you get make him hear.
I used some material from 3M for damping fan assembly noise in a telecom application and it was made of thin aluminum with an adhesive backing. The aluminum was part of the damping mechanism. I was told explicitly not to put material over the aluminum. Good thing I found out those guys at 3M are just a bunch of flakey tweak types, I will never be hoodwinked by them again. Thanks for seting me straight.

Art

P.S. Are you a material science engineer or a mechnical engineer?
 
Another Expert.......

Worrying about mechanical resonances is one thing when you're dealing with a device that's designed specifically for electrical -> mechanical energy conversion (IE, a loudspeaker), but a completely different thing when you're talking about mechanical resonances in a device designed to pass the signal electrically.
:whazzat:

Go read Chapter 26. Analog Extensions of Digital Time and Frequency generation in Analog Circuit Design edited by Jim Williams. The author describes the effect of noise and vibration on sensitive oscillator circuit. By the way these were real engineers and not audio tweaks. If I had a quater for every time I heard the phase "That shouldn't matter..." in my telecom engineering career...:magnify:
 
I'm not saying that tapping the capacitor won't have any effect on the signal. As a matter of fact, I guarantee you it will. Slight mechanical deformations of the capacitor will change the spacing between the places and cause a change in the capacitance - there's no doubt about that. However, the magnitude of it is what's important. If it's 100dB below the noise floor, it's not of particular concern. :)

It should also be noted that there's a large difference between a very tiny change in the capacitor value in an oscillator circuit that's frequency stability depends on the R*C product and and a very tiny change in the capacitance of a power supply filter capacitor feeding an amplifier with 60dB PSRR.

Even in a coupling capacitor application, a tiny change in the capacitance would only result in a very tiny fluctuation of the LF corner frequency and phase response - and even then only around the 0.1 -> 3hz range or so. And as said, the variations in frequency/phase response from that are going to be smaller than those you'd have if you moved your head an inch to the left in your room.

The only time I could see it being even mildly important were in active filter/crossover applications where frequency stability is determined by the RC product. Of course, in those applications, you shouldn't be using aluminum 'lytics anyway, seeing as their capacitance values aren't terribly stable anyway - plastic covering or not. (nonlinear with respect to temperature, voltage, etc.)

That there's a difference isn't being disputed - whether the difference is large enough to be worth worrying about is, though. I'm sure the 30 "Type R" stickers the local honda accord drivers here plaster on their cars and aftermarket 24" high spoilers really do affect the aerodynamic performance of the cars, but spending $2000 on them in the name of "performance" is an exercise in futility. Of course, that doesn't stop them from doing it anymore than it stops us audiophiles from plating our amplifier chassis' with gold.
 
Re: the post about the 3m damping material.

The 3m engineers definitely did know what they were doing when they developed the damping compound. I'm sure it's very good at its intended application, which is most likely to change the q/resonant frequency of the surface to which it is applied, so that more energy is absorbed/dissipated as heat instead of transmitted as sound.

However, it's not at all intuitive whether or not applying that to an amplifier chassis, capacitor, or whatever else would have an effect on the frequency response, distortion, or even 'sound' (if you like to use that term)

Any device is good when used in an application for which it's relevant. Applying a damping compound to a speaker cone (resonant mechanical system) to change its properties is easily measurable by any standard (aural, electrical, or otherwise), whereas applying it to the IEC power cord on your amplifier will likely result in a less than satisfactory difference, just like adding another 256mb of ram into the proper slot may well speed up your computer by a significant amount, but it will do little good if epoxied to the side of your case.
 
Intuiton vs. experience

However, it's not at all intuitive whether or not applying that to an amplifier chassis, capacitor, or whatever else would have an effect on the frequency response, distortion, or even 'sound' (if you like to use that term)

And yet you spent two very long post based on some very intuitive and simplistic models based on some pretty arbitrary numbers and simple models. I am afraid we will have to agree to disagree, as I find your aguments counter to my experience and investgations into causes for vibration induced noise in active and passive components. I have heard the results of damping capacitors, chassis, cables, and active circuits on well set up, good system. Some times they are very subtle and sometimes suprisingly audible. I leave final judgement to the individual experimentor.

Art
 
<i><b>Next thing you'll know you'll have to remove all the oxygen from the air because it leaves an "undesirable sonic signature".

It's a slippery slope indeed.</i></b>

Yes, it is.

Because we are mortal beings, we are prone to perceiving things even when there is nothing there to actually perceive. When this irrefutable fact is wholly ignored, then for some literally nothing is too absurd.

No one has done more to prove this than <a href="http://www.belt.demon.co.uk/">Peter Belt</a> who is in the business of selling what amounts to audio talismans and has people reporting audible improvements in their audio systems from such things as placing a photograph of themselves in their freezers to writing special words using a special pen over the top of the Compact Disc logo on the cover sheet in the jewel case.

For some interesting reading, you might want to check this out:

<a href="http://www.belt.demon.co.uk/product/quantum/quantum.html">The PWB Quantum Clip</a>

So, if "hearing is believing" and hearing is a perception which can include a purely psychological element, where does one ultimately draw the line? If placing a photograph of yourself in the freezer improves the performance of your system, why not say, sacrificial offerings of small animals?

At what point does one go from a healthy passion to compulsive/obsessive, to full-blown voodoo cultism?

se
 
This thread is begging some serious questions. Like what was really wrong with my technics amp, pioneer turntable and audiotechnica cartridge i had in the seventies. Judging by some simplistic engineering opinions, based on even simpler engineering models i should have blissfully enjoyed the commercially derived sound, and never even thought about lo/zero feedback, single ended power amps, vacuum tubes, idler wheel drive turntables etc etc etc. And of course for total bliss i should have added one of those beautifully sounding early eighties cd players.
What is the point of improving on perfection?
Sadly, back in the real world these silly electromechanical effects can actually make or break the sound of a system. It seems that a self imposed mental block is the only way to ignore these effects. As i would honestly prefer to live in a world where capacitors are just capacitors and all sound the same (provisions made for value and esr) (please insert similar for resistors, inductors, semiconductors, valves, pcb material, wires etc), i wouldn't mind getting some of the magic concoction which inflicts that mental block. Come to think of it i would rather buy some of the voodoo stuff that makes me hear no differences at all than any of that crooked peter belt's stuff. Along these lines i have recently been experimenting with ear plugs, but while some brands seem to work well with eliminating the audible effects of power supply cords i still can hear differences between shelf materials.
Come on guys. Tell us what you use.

peter
 
To all non believers:

This is the inside of my Technics CD transport. If the capacitors vibrational behaviour is not influencing sonics, why would Japanese (who are rather not eager to tweak) install those dampers on electrolytics.?;)
 

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Removing plastic covers from capacitors

I think i can explain it because the cover is charged by the current going trough the capacitors. In the past some articles some things have been published in France. They say that most materials will be charged and sometimes will give this charge back. Same happens in speakercables. Teflon is very difficult to charge and that is why is sounds different. In the past there was a conductive product ( using Graphite ) to stop this charging but is was only applied to film caps , cables( not on power supply!! ), resistors. It works very well. But i think if there is no plastic there is no use to apply it. But sometimes a cap has to be mounted electrically isolated. I am a bad tuper if you need more info please sent your postal address. Succes,Ed
 
<i><b>To all non believers:</i></b>

Actually, I'm neither a non-believer nor a believer. To be either would require a level of dogma that I'm simply not comfortable with.

Why is it assumed that anyone who doesn't blindly accept another's dogma is a "non-believer"? That's like a theist assuming that anyone who isn't also a theist must be an atheist. The concept of being neither simply doesn't register for some reason.

<i><b>This is the inside of my Technics CD transport. If the capacitors vibrational behaviour is not influencing sonics, why would Japanese (who are rather not eager to tweak) install those dampers on electrolytics.?</i></b>

Allow me to turn this around on you.

If putting a photograph of yourself in your freezer does not influence sonics, why would anyone do such a thing?

Are you a believer in freezing photographs of yourself to influence sonics? Or are you a non-believer? If a non-believer, how can you possibly discount the positive effects reported by others?

se
 
Peter Daniel said:
I've also heard that removing plastic covers from electrolytics improves sonics. You got two different materials interacting with ea. other. When you remove one the vibrational properties change and possible change in sound signature could be observed.

Sorry, I still don't believe... at all!

Your mind is powerful. I you want believe, you will believe.

Example: As I have stated, I don't believe in real tweaks. I was at the hifi exibition (Hifimässan at Hotel Arken) here in Göteborg and they had a shelf suspended with springs. I listened with the shelfs firmly attached. Sounded OK. Then they made the shelfs hanging in springs. I thought it actually sounded better. I'm not sure if I had heard a difference in a blind test. I'm more or less convinced of it. Your mind is powerful in decieving or believing.

BTW: Was the discussion only about electrolythic caps in aluminium with a plastic cover? Then I really don't believe it. It's also easy to remove the cover, this I can agree with.