Are these actually Wimas?

[amc184]

After laughing at all the auctions for obvious fakes on eBay, I was stupid enough to bid on an auction for some 100nF 100V Wima MKS2 capacitors. I use heaps of them, so I thought a bulk buy would save me some money.

They turned up, but they look like no Wimas I've seen before (and I've bought a few). The photo below shows the caps I got from eBay on the left beside some 220nF MKS2s I got from a trustworthy (but more expensive) source.

Are these actually Wimas?

[QSerraTico_Tico]

Originally Posted by amc184

After laughing at all the auctions for obvious fakes on eBay, I was stupid enough to bid on an auction for some 100nF 100V Wima MKS2 capacitors. I use heaps of them, so I thought a bulk buy would save me some money.

They turned up, but they look like no Wimas I've seen before (and I've bought a few). The photo below shows the caps I got from eBay on the left beside some 220nF MKS2s I got from a trustworthy (but more expensive) source.

Are these actually Wimas?

Left older, right newer.

[amc184]

Nope, both very new.

All the Wimas I have seen are stamped with 'WIMA', the capacitance and rated voltage on the front, and a batch code on the back, all in gray or black ink.

The suspect caps are stamped on the top for capacitance, tolerance and voltage rating in white ink. Nowhere does the name 'WIMA' appear, so I a hesitant to even call the fakes.

[amc184]

Nevermind.

I just got an answer from Wima themselves, these are the real deal. I'm glad them look the time to answer my email, to many companies don't bother.

[pjp]

This makes me wonder - what is so special about a WIMA ?

Given the extreme simplicity of these caps - polyester film is the same, regardless of where its manufactured, and the electrodes are always vacuum sputtered - I can't imagine there being any difference between polyester film capacitors from different manufacturers.

What is different about a WIMA that makes it a better cap ?

[amc184]

polyester film is the same, regardless of where its manufactured, and the electrodes are always vacuum sputtered

I don't agree. Never underestimate the capacity for a manufacturer to take a straightforward job and do it badly.

That said, no, there is nothing really special about Wima, I also use film capacitors from Illinois Capacitor, Vishay BC and more. Any manufacturer with a decent reputation is good enough for me. I tend to focus more on dielectric material and construction type than brand, as long as there is a brand.

The issue in this thread was that I had bought brand name capacitors which I thought may have been generic. My concern was misplaced.

[osscar]

Mine Wima (I believe they are original-bought from trusted supplier ) are printed in black lettering (MKS 4).

[Captain archer]

These's wima's are real i've bought some of these to, but from a normal shop so not from ebay.
Here in holland they sometimes apear as the one's with the white lettering on top and sometime with black letters on the side (sometimes with silver text to).
i've also salvaged some of these caps (white letters on top) from old medical equipment so these seem to be the older types or something?
and it seems to me that suppliers of medical equipment check their sources.

Greets Captain archer out.......................!

[qusp]

yep, real alright, the older stock mks2 dont have any writing on the side at all, just on top. mainly in the smaller values like you picture. I was concerned too with some I got in a kit, but after recieving the same type from several other reputable suppliers since i'm not worried. its worth enquiring though, especially when the caps in question might be in a power supply perhaps even high voltage 8O. also I guess there are several manufacturing plants for the same models too perehaps. wima are good, but I agree I will happily use similar films from vishay/BC, evox/rifa (I actually prefer evox/rifa/kemet) kemet's PPS are superb! IMO

[Elvee]

Originally Posted by pjp

This makes me wonder - what is so special about a WIMA ?

Given the extreme simplicity of these caps - polyester film is the same, regardless of where its manufactured, and the electrodes are always vacuum sputtered - I can't imagine there being any difference between polyester film capacitors from different manufacturers.

What is different about a WIMA that makes it a better cap ?

Wima is among the best, but not THE best:
"Best" film cap you've never heard of?

In this example, a rather old C280 from Mullard is better. Older, tubular types are even better.