Wima differences?

[tube-a-lou]

Hi all,
An cap question if your looking at Wima small capacitors like .1uf 100volt types,
underneath some are filled with red epoxy and some with yellow epoxy, is that a
code of some type?

Thanks

 

[jefferylhenr]

Hi all,
An cap question if your looking at Wima small capacitors like .1uf 100volt types,
underneath some are filled with red epoxy and some with yellow epoxy, is that a
code of some type?

Thanks

It’s a top secret code… for sure

 

[eiraved]

Take the red epoxy and you'll understand the true nature of the Wima Matrix.

 

[Okke 70s]

Wima makes a whole bunch of metal film cap series, like "MKS II". Series overlap in available ratings, so I suspect you are looking at two capacitors of the same ratings, but from different series.

 

[cademan]

underneath some are filled with red epoxy and some with yellow epoxy, is that a
code of some type?

Show us what you are looking at.

There are soooo many different types of capacitors.

 

[zaibatsu]

No code, I have different batches of Wima MKS from different years (but same PN, from memory) with both yellow and red fill.

I don't recall the % tolerance of the parts, but fairly sure that is indicated elsewhere.

 

[mr.muddles]

What is the difference between MKS and FKP?

Who wants to recommend me a 100pf 50+V WIMA cap?

 

[CohibaJoe]

Hi all,
An cap question if your looking at Wima small capacitors like .1uf 100volt types,
underneath some are filled with red epoxy and some with yellow epoxy, is that a
code of some type?

Thanks

Nice write up (and updated) for Caps.
http://www.humblehomemadehifi.com/Cap.html

 

[zaibatsu]

What is the difference between MKS and FKP?
Who wants to recommend me a 100pf 50+V WIMA cap?

MKS = Metallized Polyester
MKP = Metallized Polypropylene
FKP = Film / Foil Polypropylene

Choice depends on application, the latter two are superior for small values, while MKS is useful for larger values (particularly for replacing small value electrolytics, up to 6.8uF, even 10uF) where MKP and FKP are physically too large. In your case (100pF), FKP is likely the best choice.

 

[ghamilton]

MKS = Metallized Polyester
MKP = Metallized Polypropylene
FKP = Film / Foil Polypropylene

Choice depends on application, the latter two are superior for small values, while MKS is useful for larger values (particularly for replacing small value electrolytics, up to 6.8uF, even 10uF) where MKP and FKP are physically too large. In your case (100pF), FKP is likely the best choice.

Good answer!

 

[mr.muddles]

MKS = Metallized Polyester
MKP = Metallized Polypropylene
FKP = Film / Foil Polypropylene

Choice depends on application, the latter two are superior for small values, while MKS is useful for larger values (particularly for replacing small value electrolytics, up to 6.8uF, even 10uF) where MKP and FKP are physically too large. In your case (100pF), FKP is likely the best choice.

So FKP for the smallest values...

Is there any consensus on what is best to use between polyester and polypropylene when space/cost is not a concern but just best performance for audio and when the values overlap for both series?

 

[MissionX]

So FKP for the smallest values...

Is there any consensus on what is best to use between polyester and polypropylene when space/cost is not a concern but just best performance for audio and when the values overlap for both series?

I'd like to know this as well

 

[Lavane]

The MKP's will work just fine in most cases.

 

[wyn palmer]

So FKP for the smallest values...

Is there any consensus on what is best to use between polyester and polypropylene when space/cost is not a concern but just best performance for audio and when the values overlap for both series?

Polypropylene. Lower distortion, better consistency, etc. etc. etc.
When I design preamps I use caps in this order of preference:
1. polypropylene
2/3. C0G MLCC , PPS (polyphenylene sulphide)

All the rest.
Polyester films can be good, but they are not as good as those above and tend to show substantial batch to batch variations.

All three provide extremely low distortion (<<-120dB at ac signal levels of 3v RMS, 1kHz) and are extremely temperature stable and with almost unmeasurable DC bias dependence.

I know this because what literature exists supports this, and I've independently tested this in some designs.
I've excluded exotics like Teflon, that may be even more ideal but have other issues, and even more ideal really doesn't matter.

 

[FinalVinyl]

What is the difference between MKS and FKP?

Who wants to recommend me a 100pf 50+V WIMA cap?

A value that low I would use a silver mica. They're cheap and last forever

 

[dlucy]

Polypropylene. Lower distortion, better consistency, etc. etc. etc.
When I design preamps I use caps in this order of preference:
1. polypropylene
2/3. C0G MLCC , PPS (polyphenylene sulphide)

All the rest.
Polyester films can be good, but they are not as good as those above and tend to show substantial batch to batch variations.

All three provide extremely low distortion (<<-120dB at ac signal levels of 3v RMS, 1kHz) and are extremely temperature stable and with almost unmeasurable DC bias dependence.

Great to hear this from an authoritative source. Thank you!

Many of the WIMA are now showing PET instead of polypropylene. Is PET the same, worse, better, @wyn palmer ?

Very good to see love for the C0G MLCC caps....

 

[wyn palmer]

Great to hear this from an authoritative source. Thank you!

Many of the WIMA are now showing PET instead of polypropylene. Is PET the same, worse, better, @wyn palmer ?

Very good to see love for the C0G MLCC caps....

PET is a polyester capacitor- Polyethylene Terephthalate. The previous description includes them.
Film/foil capacitors - WIMA – Competence in Capacitors
In the above link Wima actually describes some of the differences (i.e. dissipation factor) and the preferred uses. PP for Audio, PET for general purpose, for example.

 

[wyn palmer]

For those who are interested in the Dielectric Absorption differences for various caps:
1982-10-13_EDN_Pease-capacitor-soakage.pdf
I recently had occasion to measure this for some Murata C0G 22nF caps and some Wima 22nF PP caps and I found it to be very similar in the 1s-100us time range that is relevant to audio design. This matched the 40year old Bob Pease results in the article above.

 

[crispycircuit]

I like Wima FKP in my tube amps