Capacitor mystery solved

[PinkFloyd]

Have a read

[Deleted]

The company then made a matrix of otherwise identical polypropylene metallised film capacitors by altering undisclosed production process variables and found a construction that offers the least electrically-induced mechanical resonance

The cynic in me suspects that a new capacitor label is about to be released at a premium price, based on these very wishy washy,sketchily detailed results. These kind of tests have been done previously, even commented upon by Douglas Self. (below)
I wonder if there have been any ex Blackgate personnel involved ?
SandyK

 Capacitors affect the signal passing through them in a way invisible to
distortion measurements.
Several writers have praised the technique of subtracting pulse signals passed through two different sorts of capacitor, claiming that the non-zero residue proves that capacitors can introduce audible errors. My view is that these tests expose only well-known capacitor shortcomings such as dielectric absorption and series resistance, plus perhaps the vulnerability of the dielectric film in electrolytics to reverse-biasing. No-one has yet shown
how these relate to capacitor audibility in properly designed equipment.

[leo]

Try skinning a lytic cap of its sleeve obviously making sure the bare aluminum does not touch any active circuitry.
I once mocked a guy who suggested this but tried it anyway seeing as though it was free, lesson learned never mock anything without trying it first

[PinkFloyd]

leo said:

Try skinning a lytic cap of its sleeve obviously making sure the bare aluminum does not touch any active circuitry.
I once mocked a guy who suggested this but tried it anyway seeing as though it was free, lesson learned never mock anything without trying it first

I always do this with output caps and polish them up with brasso too...... don't ask why but I swear they sound better

[leo]

This is one tweak I very rarely discuss, not because I try to keep it as a secret but because I'm actually embarrassed about saying such a thing BUT I do know for a fact it works because I've tried it and compared.
Only thing I can think of what causes the change is down to the sleeve having some vibration effect on the case, fook knows tbh.
I do have very good hearing and not one to be fooled by placebo but the thing I heard was a more airy sound, its not massive but the sort of thing thats noticeable.

[Deleted]

Leo
I have read previously that to get some kind of audible effect out of an electrolytic capacitor you normally need to strike it quite sharply, and the result is only a barely audible thud.
I think that modern electrolytic capacitors would be virtually impervious to the kind of effect you describe.

A tight sleeve is more likely just to alter the frequency of any mechanical resonance ?
Alex

[leo]

sandyk said:

Leo
I have read previously that to get some kind of audible effect out of an electrolytic capacitor
you normally need to strike it quite sharply, and the result is only a barely audible thud.
Alex

Yes, I also read the same and as mentioned above I rarely talk about such a thing as skinning capacitors, it sounds stupid I agree but this is one of the very few tweaks I found that did make a difference in this particular test, I've only actually tried it once in a cdp and the effect was there.

I wish I never mentioned it now

[Deleted]

Leo
All the more reason to use a JLH where there are any small effects that could conceivably be amplified !
Alex

[PinkFloyd]

Don't worry about it Leo, I agree with you it does make an audible difference just the same as swapping out a metal volco knob for a plastic one does. Cap skinning is free so one tweak that can't be labelled a "rip off"! Next time you skin them be sure to polish the cap surface with brasso until you can see your face in it, I find this also improves SQ marginally. Add a cap damper (a sticky backed felt pad) and you're good to go man.

Another thing you can try is a blob of butyl tape between the capacitor and the PCB and also a blob on the top of the cap. This stuff will stick to water and it's much better than blu tack.... the roll that reddiseals supply is ENORMOUS, don't be fooled by the picture in that link! This stuff has thousands of uses around the home and a roll will last you a lifetime..... one of the best finds I have ever made

[dc]

what amp is that?

[Deleted]

Add a cap damper (a sticky backed felt pad) and you're good to go man.

Are you a frigging mind reader, or something ? ;D

[PinkFloyd]

dc said:

what amp is that?

The uber rare White Noise Audio Mark lll.

sandyk said:

Add a cap damper (a sticky backed felt pad) and you're good to go man.

Are you a frigging mind reader, or something ? ;D

Yes. Styop thinking about that young girl you dirty bugger I'm trying to get to sleep here!

[rowuk]

If we immobilize the caps, then spikes on preamps should offer no more benefits!

Microphony is even present in cables - and is VERY audible. Any recording engineer can sing songs about cables that measure ok but introduce non-RF noise.

If vendors start removing the covers, we will have a much harder time backwards engineering electronic gear..............

Lets not forget, the top of the electrolytic cap is designed to vent instead of blowing up. Be careful what you glue there! Especially before a circuit has been fully tested!

[Deleted]

Robin and Miguel
We are missing the point of these claims. They aren't talking about microphonic problems.

"mechanical resonance excited in the capacitors by ELECTRICAL signals applied to them was a problem. These resonances affected the filtering effect of the capacitors."

Alex

[rowuk]

Alex,
if applying AC to a cap gets it mechanically resonating with an audible effect, then we have the wrong cap. This would have to be caused by magnetic flux from another device, or inductance in the cap, coupled with a VERY strong signal capable of moving the capacitor "plates". If the inside/outside of the cap is that "loose", microphony is also an issue.

[Deleted]

Robin
That is why I suggested that this shouldn't be a problem with most modern capacitors.
It still sounds like another commercial PR beatup to me, as it is so sketchy on detail.
Alex

[leo]

Ok, I think its a mistake posting this but here goes

I've had 4 x 100uf Rubycon ZL caps buring in on the cap rack.
I have skinned two and left the others as standard.

The PCM1794 dac uses a pair of caps for Vcom, I've always found the type of capacitor used here has an influence on the sound, normally I use low leakage solid aluminum.

Anyway I've now compared the skinned ZL's against the non skinned in this position.
The non skinned ones made the sound have some slight top end sharpness, a little glassy, fitting the skinned ZL's gave quite an interesting result , the sharpness was reduced! this is quite clear to hear here

I'm now confused and have no idea why this is happening, I'm going to try the same test in other positions but the difference is plain in this particular application chaps

[aman]

In some guitar-amp forums I attend there been some buzz about the oil-filled-caps from cars being the real mojo....and those amps see a lot of vibrations.

[PinkFloyd]

fitting the skinned ZL's gave quite an interesting result

Gives a whole new meaning to the phrase "skin up"

[leo]

admin said:

fitting the skinned ZL's gave quite an interesting result

Gives a whole new meaning to the phrase "skin up"

I tried the skinned ones in the decoupling supplies, I didn't notice much difference there, worth a go though and cost nowt

[sometrolls2]

Wouldn't any field the cap has be altered is the coating is to some extent vibrating/flapping about, especially if it was metal and had a grain?

[charleyphogg]

leo said:

Ok, I think its a mistake posting this but here goes

I've had 4 x 100uf Rubycon ZL caps buring in on the cap rack.
I have skinned two and left the others as standard.

The PCM1794 dac uses a pair of caps for Vcom, I've always found the type of capacitor used here has an influence on the sound, normally I use low leakage solid aluminum.

Anyway I've now compared the skinned ZL's against the non skinned in this position.
The non skinned ones made the sound have some slight top end sharpness, a little glassy, fitting the skinned ZL's gave quite an interesting result , the sharpness was reduced! this is quite clear to hear here

I'm now confused and have no idea why this is happening, I'm going to try the same test in other positions but the difference is plain in this particular application chaps

Could it be similiar effect of hitting a drum skin with your hand on it as apoosed to without ur hand on it? Drasticly overstated, but it serves the point.

As far as polishing.... chrome always makes cars go faster , but on the serious side, maybe polishing removes the slight imperfections, ridges or whatnot and gives casing consistant thinkness?

[Deleted]

As far as polishing.... chrome always makes cars go faster , but on the serious side, maybe polishing removes the slight imperfections, ridges or whatnot and gives casing consistant thinkness?

O.K. I'm in my concrete bunker, fire away Mike !

Not only does it look good and put the listener in the right frame of mind to appreciate the music, it also makes for a much better surface for the adhesive felt, or other dampening material to stick to ! ;D
If Leo and Mike both say that doing this makes an improvement to SQ, I accept without reservation what they are both saying.
Alex

[leo]

sandyk said:

As far as polishing.... chrome always makes cars go faster , but on the serious side, maybe polishing removes the slight imperfections, ridges or whatnot and gives casing consistant thinkness?

O.K. I'm in my concrete bunker, fire away Mike !

Not only does it look good and put the listener in the right frame of mind to appreciate the music, it also makes for a much better surface for the adhesive felt, or other dampening material to stick to ! ;D
If Leo and Mike both say that doing this makes an improvement to SQ, I accept without reservation what they are both saying.
Alex

Please have a laugh mate I can honestly say if I read such a thing myself I'd think what a load of B******s, its not often I'd try or even post such a crazy thing
I had to try it though, cap skinning only had the really noticeable affect on the Vcom pins so won't be faffing about doing it in everything ;D

[Deleted]

If Leo and Mike both say that doing this makes an improvement to SQ, I accept without reservation what they are both saying.
Alex

Leo
I meant that !
I would imagine that the tight skin may be affecting the capacitor's mechanical resonances. This suggests to me that suitable dampening material like adhesive felt, could be beneficial.
Alex