Polyester metallized film cap vs polypropylene metallized film cap

[Positron]

I should add that materials, termination techniques, gauge and length of leads all make a sonic difference.
Very few brand capacitors are sonically accurate, but one or two brands are. Larger value polypropylene capacitors can
be near perfect, if not perfect in absolute terms (not alter the sonics in any way).

cheers

pos

 

[Markw4]

Larger value polypropylene capacitors can be near perfect, if not perfect in absolute terms (not alter the sonics in any way).

Some people well known in the high end audio world for great sounding products would disagree. Also, IME large value polypropylene caps can alter sound of low and or line level signals drastically (yet they can sound good in speaker crossover applications). I have some polypropylene and foil caps as large as 160uf which turned out to be a waste of money. Even Clarity and or REL caps affect the sound more in larger values.

 

[Positron]

"Some people well known in the high end audio world for great sounding products would disagree. Also, IME large value polypropylene caps can alter sound of low and or line level signals drastically (yet they can sound good in speaker crossover applications). I have some polypropylene and foil caps as large as 160uf which turned out to be a waste of money. Even Clarity and or REL caps affect the sound more in larger values."

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Are "Some people well known in the high end audio world for great sounding products" you refer to using Clarity and REL
capacitors? Even the small values of said caps are not very accurate, let alone the larger values, in absolute terms. Personally I
have worked/tested values of up to 100uf (have not used/tested larger values) in the lab that were quite accurate, and musical in
absolute terms, via sophisticated listening tests.

Unless one is using accurate parts, the components are missing musicality, accurate harmonic structure, spatial qualities,
dynamics etc from the recording. In otherwards, lacking live sound quality.

cheers

pos

 

[Markw4]

Accurate measured how? For capacitance? For some other parameter(s)? Do you know what the caps lose? I thought they sounded great too, until it was brought to my attention what was wrong.

And I'm not supposed to get into who exactly. If you really want to know for some good reason, you can PM me.

 

[Positron]

"Accurate measured how? For capacitance? For some other parameter(s)? Do you know what the caps lose?

I'm not supposed to get into who exactly. If you really want to know for some good reason, you can PM me."

Please re-read my previous post as I clearly answer your question(s), sonically.

pos

 

[Extreme_Boky]

The sound-coupling large film capacitors should be:

• tightly wrapped in copper foil. The copper foil should be grounded to the chassis potential via the shortest mean possible, using a fairly thick multistrand cable.
• (if possible)... their dielectric should be polarised by means of applying DC potential across them. Otherwise, they will influence the sound in such a way as what Mrakw4 described a few posts back - post#72
• be avoided no matter how "good" they may appear to be sounding.

Re electrolytic caps used as sound coupling caps, the best result can be obtained if 2 are used in an "anti-series" configuration of two caps, with a middle point connected to either + rail or - rail (depending, of course, how you connected the two electrolytic caps). Again, all caps need to have their electrolyte/dielectric polarised to sound good.

But, the best result I obtained in the end was... when I removed all sound coupling caps from my sound reproduction chain (sans the x-over caps in speaker cabinets...)

 

[Positron]

"The sound-coupling large film capacitors should be:

• (if possible)... their dielectric should be polarised by means of applying DC potential across them. Otherwise, they will influence the sound in such a way as what Mrakw4 described a few posts back - post#72
• be avoided no matter how "good" they may appear to be sounding."

1. Specialized, sophisticated listening tests are required to determine how accurate a capacitor is. A capacitor, small or large up to 100ufd can be near if not perfectly accurate. (I have only tested up to 100ufd value.) This means spatial, dynamic, frequency response is accurate and natural. Read on for more info.

2. Polarizing does not necessarily increase sonic accuracy, naturalness.

3. From Post #72:

"They can lose all the space/soundstage_depth"

What Mark is describing is masking. In such cases, true inner detail is "lost", covered due to DA and frequency response abnormalities of the part in question; in this case the capacitor. There are large value polypropylene capacitors that are accurate and leave no spacial information etc behind. Again, this via specialized sophisticated listening tests. The next paragraphs will explain more.

"Re electrolytic caps used as sound coupling caps, the best result can be obtained if 2 are used in an "anti-series" configuration of two caps,
with a middle point connected to either + rail or - rail (depending, of course, how you connected the two electrolytic caps). Again, all caps
need to have their electrolyte/dielectric polarised to sound good."

One of the main problems with electrolytic caps is the high dielectric absorption (DA) figure (electrons sticking to the insulating material and gradually coming off over time). The effect is to decrease dynamics, cause spatial problems, mask true inner detail.

The DA for an electrolytic is ~ 7% vs the DA for polypropylene is ~ 0,02%, Using 20log equation, there is ~50db difference between them. Inner detail is lost with higher DA.

Dimension, termination techniques, materials, can and usually cause frequency response abnormalities causing Masking. Designed improperly and inner detail, spatial information is lost, even with small to large polypropylene capacitors.

Another consideration is that the signal voltage across any capacitor varies with frequency. The reactance of a capacitor is

Xc = 1/2pi times F times C..... F is frequency, C is capacitance, Pi is ~3.14. It means that due to frequency, the time varies for the electrons to leave the insulating material.

"But, the best result I obtained in the end was... when I removed all sound coupling caps from my sound reproduction chain (sans the x-over caps in speaker cabinets...)"

Could be since dual, poor quality sans resistors along with the poor quality capacitors used. Typical sans are also inductive.

One other point. With quite small output amplifiers, amplifier clipping (rectification effects) often occurs with said weird sound.

Thus small coupling capacitors are used to minimize rectification effects. However, accurate capacitors would cause a thin sound.The "solution" is to use inaccurate, full sounding very small ufd capacitors. However, such capacitors tend to mask real inner detail, losing spatial info. Imagine the loss of large, full sounding capacitors in other places. It is a loss loss situation.

cheers

pos