Polystyrene Caps For Filters

[jacco vermeulen]

My half-educated guess is that the quality of caps depends on the foil type, construction type, homogenity of the foil thickness, and winding tightness technology.
For the polystyrene cap era, it's very likely that the sota winding machinery was of German manufacture.

Explains why top notch Styrene caps from the late '70s till halfway the '90s were predominantly North Eurica production; ITT, MIAL, Phily, Siemens.
The KS caps i measured are commonly way more accurate than their nominal +/- 1% spread, higher voltage Polystyrene caps could also be special ordered with 1% accuracy.
A diyA member also measured one of the boxed Phily caps : Measured Differences Between Capacitors for Audio Applications

The most striking about the Greeny Russians (apart from dimensions) is the giant spread in accuracy, 0.5% to 5%.
Dirt cheap though, for someone with a use for bulky 250V caps.

[CeeVee]

Thanks Jacco...your half educated guess is a goldmine for me

[NagysAudio]

The very best capacitors for this type of job are the original ERO capacitors from Germany. Especially the MKP1837's and MKT1822's. The new production Vishay/Roederstein are not as good. Luckily, you can find just about any value of the original NOS EROs on eBay for pennies.

[jacco vermeulen]

I have my serious moments (not often though).

Odd part about Mr Hoffman's page is that 600V AuraT caps are specced at 5%, btw.

[CeeVee]

Originally Posted by jacco vermeulen

The most striking about the Greeny Russians (apart from dimensions) is the giant spread in accuracy, 0.5% to 5%.
Dirt cheap though, for someone with a use for bulky 250V caps.

I'm looking for alternatives to the Panasonic ECQP range for my Orion ASP upgrade and it seems Digikey is running out of these ( at least the 1% types i want )....


...seems they were discontinued June 2008....so stocks are going.

[wrenchone]

One for Jaco, as he seems to be Mr. Polystyrene. I picked up some little orange Siemens box-style polystyrenes (at least they say "KS" on them), with the leads in the corners. It looks like the type may be GSE. Sound familiar? Also picked up in the same run were some more of the Mial red box-style caps, and a handful of Rifa PHE307 polycarbonates. The Rifas are very well-made with very neat and heavy zinc spray at the ends with the leads buried securely therein. I may use them for that "warm and cozy" polycarbonate sound.

[jacco vermeulen]

Here you go.
(i own 15000 of the orange KS fellas, so i likely rank Mr Poly)

(i've got a headache from driving 100 miles through snow, is the pits with an unstable neck, 02.17am here, hence the swift response)

[wrenchone]

Thanks for the pics - a help to cap scroungers everywhere... Mine look a trifle different. They just have the value and tolerance printed on the top, with the Siemens logo on the side and KS 63V ,and GSE 01.85.

The local surplus stores have a surprising wealth of good polystyrene and polypropylene caps, perhaps due to the modem and telecom companies in the area. If I get a little spare time (HA!) I should compile a little menengerie of parts. I also have some interesting little bluish-silver Roederstein radial caps with laid-in (though rather thick) leads - you can even see the little hollow in the center as a result of the manufacturing process. I suspect these aren't the best caps in the universe, but they're certainly compact.

[wrenchone]

On closer perusal, the Siemens caps look like the smaller members of the KS57 series caps in the picture.

If I collect enough cool and colorful caps, I can color-coordinate them. I have two "citrus series" of RIAA amps at present, one "oranges and lemons" preamp with big yellow polypropylenes and some bright orange BC MKPs, and a "lemon-lime" preamp with the same yellow polypropylenes and the green Russian polystyrenes.

[jacco vermeulen]

GSE points to the manufacturing date (pff, German gründlichkeit)

The KS series were manufactured till 1995/6.
Official Siemens code is a B series number, B31521 in the early 80s, B31531 from late 80s. (i'm a number mental image fool)

Both series and cap value determine the shape of the box.
Late series caps were labelled S+M (cooperation between Siemens and Matsushita) , i'll post an image tomorrow.

I have a hickload of the black ones too, ITT manufacture, a diyA member offered to help me to a stash of Yellow Phily KS cubes in a range of values. Life can be good.