In "6 - 24 crossover" thread there was some time ago a short discussion about the quality of WIMA capacitors. Also a little about the "mysterious" about the "Black box WIMA's". I decided to ask about them and also which WIMA type to select today for audio. After a couple of mails and some waiting I got this information. It is information only.....I don't sell WIMA's 🙂
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The BlackBox was a special edition that we developed in early 2000.
With this special edition, the goal was not to be pricely competitive against our competitors. The goal was to deliver the best sound experience.
After several research and testing, we concluded that the use of a thicker dielectric drastically minimizes vibrations inside the capacitor, which has a positive effect on the sound quality.
We used a polypropylene dielectric with a polyester foil metallized with aluminum. This dielectric was thicker and as you can see very clearly the BlackBox edition has physically larger dimensions than the standard capacitors.
When the dielectric is thicker and you need more raw material for the caps and potting, the capacitors have a higher manufacturing cost and value.
The BlackBox standard alternative today will be direction MKP10. However, it is very important if you want extreme sound quality and if there is enough space available, that you consider a higher dielectric strength and higher nominal voltage due to the film thickness: The higher the nominal voltage, the thicker the foil.
What was then a BlackBox 250 VDC ... today should be something like the MKP10 series in 400 VDC, because of the thicker foil.
Example:
MKP 10, 400 VDC, 0.33 µF 20% = BlackBox 250 VDC, 0.33 µF 20%.
Nevertheless, the 250 VDC´s capacitors are also very optimal and beloved for sound engineering. This is because of the high quality of WIMA capacitors.
Most of our audio customers today also prefer a capacitor with a lower tolerance: 5%. Somehow this lower tolerance also has a positive effect on the quality of the sound.
I hope I could help you guys a bit further.
Stay safe and healthy.
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The BlackBox was a special edition that we developed in early 2000.
With this special edition, the goal was not to be pricely competitive against our competitors. The goal was to deliver the best sound experience.
After several research and testing, we concluded that the use of a thicker dielectric drastically minimizes vibrations inside the capacitor, which has a positive effect on the sound quality.
We used a polypropylene dielectric with a polyester foil metallized with aluminum. This dielectric was thicker and as you can see very clearly the BlackBox edition has physically larger dimensions than the standard capacitors.
When the dielectric is thicker and you need more raw material for the caps and potting, the capacitors have a higher manufacturing cost and value.
The BlackBox standard alternative today will be direction MKP10. However, it is very important if you want extreme sound quality and if there is enough space available, that you consider a higher dielectric strength and higher nominal voltage due to the film thickness: The higher the nominal voltage, the thicker the foil.
What was then a BlackBox 250 VDC ... today should be something like the MKP10 series in 400 VDC, because of the thicker foil.
Example:
MKP 10, 400 VDC, 0.33 µF 20% = BlackBox 250 VDC, 0.33 µF 20%.
Nevertheless, the 250 VDC´s capacitors are also very optimal and beloved for sound engineering. This is because of the high quality of WIMA capacitors.
Most of our audio customers today also prefer a capacitor with a lower tolerance: 5%. Somehow this lower tolerance also has a positive effect on the quality of the sound.
I hope I could help you guys a bit further.
Stay safe and healthy.
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I have a bit more information as I was curious about the tolerances and how 5,10 and 20% capacitors was "produced". Some questions I asked was conditional so the answer for one question indirectly answers the next. But below are the "full" Q&A.
Q:
Are the 20%, 10%, 5% from same production run meaning that you group the capacitors by measure the capacitance of each capacitor?
A:
Yes
Q:
This method will also cause that I will only see a capacitor close to the nominel value in the 5% group?
A:
Yes
Q:
Or do you “trim” or “tune” the production to produce the 5 or 10% groups?
A:
No
Q:
If this is the case I might get a higher quality capacitor in the 5% group?
A:
In the 5% group you can have even near + 5% tolerance = more capacitance = 10 µF + 5% = 10,5µF… but also you can have till almost – 5% = 9,5 µF (normally this never happens).
Q:
Are the 20%, 10%, 5% from same production run meaning that you group the capacitors by measure the capacitance of each capacitor?
A:
Yes
Q:
This method will also cause that I will only see a capacitor close to the nominel value in the 5% group?
A:
Yes
Q:
Or do you “trim” or “tune” the production to produce the 5 or 10% groups?
A:
No
Q:
If this is the case I might get a higher quality capacitor in the 5% group?
A:
In the 5% group you can have even near + 5% tolerance = more capacitance = 10 µF + 5% = 10,5µF… but also you can have till almost – 5% = 9,5 µF (normally this never happens).
You will get more wound film capacitors on the lower end of the range, because that's cheaper
to make. The production tolerance peak is tuned a little lower than exactly nominal.
Matching the values between channels is fine, but a higher voltage rating is better.
to make. The production tolerance peak is tuned a little lower than exactly nominal.
Matching the values between channels is fine, but a higher voltage rating is better.
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If they had a production run for each tolerance then if I purchased a lot of 20% caps I would get some close to the nominel value but now I know that I need the 5% to get close to the nominel value. I think that was the question I was most curious about. This may be important for use in filters but for audio coupling cap it is not important as I can still match two 20% caps for left and right channel if I want two caps that has about same value.
Hello Meper,
this is the reason why I use the WIMA FKP in filters (often available in 2,5% and 5% - tolerance).
This was also the reason why I tried the Mundorf caps in my newer 6-24XO-build. They are rated at 3% tolerance. But not so many capacitances available -
especially in the nf - range. I needed 100nF ( Mundorf) and the 47nF are WIMAs.
Greets
Dirk
this is the reason why I use the WIMA FKP in filters (often available in 2,5% and 5% - tolerance).
This was also the reason why I tried the Mundorf caps in my newer 6-24XO-build. They are rated at 3% tolerance. But not so many capacitances available -
especially in the nf - range. I needed 100nF ( Mundorf) and the 47nF are WIMAs.
Greets
Dirk
I wonder what the "yield" is after a production run in the different "groups of precision". One should think as the production gets "modernized" it will be difficult to produce a cap that if off more than 10% of the nominel value. But an important information to know how many "precision groups" there are of a specific production run. Depending of what you want of course. If you want a cap as close as possible to the nominel value it is important.