Metropoulos Forum

After a PM from a fellow board member asking what a mustard actually looked like inside, I got prompted to do this again. I had previously torn one (and a radial mustard) apart after stupidly blowing one up on my sencore tester, having failed to lower the voltage before testing... These pics must be on my old hard drive though (which has died a death) as I can't find them on my computer so I started again.

On finding a .022uF mustard with short legs that actually tested very high for ESR (like four times my others) I thought this would be a perfect candidate.

http://i255.photobucket.com/albums/hh15 ... C01282.jpg" onclick="window.open(this.href);return false;

So, from left to right we have...
630V .022 Mallory 150
400V .022 C296 Mustard
400V .022 Sozo standard
and I got curious so I added a 716P Sprague Orange Drop (remember, other orange drop types will vary)

http://i255.photobucket.com/albums/hh15 ... C01282.jpg" onclick="window.open(this.href);return false;

One thing I did notice straight away, was that construction-wise, the Sozo's were less neat and tidy with regards to the legs...
Mallories were very neat and tidy with regards to construction. Mustards were nearly as good. Spragues a little bit more ratty.

You will notice that the mallories have a narrower dielectric film than the C296, but the Sozo's are about the same. The 716P's are obviously a fair bit wider.

http://i255.photobucket.com/albums/hh15 ... C01283.jpg" onclick="window.open(this.href);return false;

Top is Mallory, next is Mustard, then Sozo, then Sprague.

The next thing to notice is that the Mallories are actually of a metallized film type, rather than a definite film/foil construction. This is very thin, and tries to return to it's contructed shape as soon as it is unravelled.

The Sozo's are a definite film and foil construction, although maybe a bit thinner foil than the C296 Mustards.

The Sprague 716P's are actually closer in this respect, although wider, and oval, rather than cylindrical. It should be noted that these are a 630V rated cap though. The film itself is also slightly different than the others, less strong, creases easier. This is much the same as the radial mustards that I recall too, except they seemed thinner in the foil department (although I can't actually recall what value/voltage rating it was that I deconstructed. I installed my last few in a keyboard PCB repair a while back... )

So, now you know why the Mallories sound markedly different.


Edit: Sorry, couldn't be bothered to resize my photo's so had to post links instead.

Thanks, very interesting

Awesome thanks, so the 0.022uf 400v mustards should be foil like? like in the picture?

They should indeed. The mustards are directly below the curly mallory mess. Lower voltages (like the .68uF's for example) have slghtly thinner foil and film. They don't feel quite as robust upon dismantling (from what I recall...)

Thank you so much Demonufo, you're the best !!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I have a question what is the size of the epoxy coating of the Mullard capacitor ? 1mm ? Less ?
I wanted to know this since a long time.

Thank you

From memory I'd say it was a shade less than 1mm.

Thanks a lot

I find that metalized film sounds clearer and tighter. Maybe because the layers are thinner?

Several reasons I suspect. Most metallized polyester will be technically superior and self healing. I'd go with clearer for sure, but in general I find them a little bit less interesting.