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tiroth 5th June 2002 02:16 AM

Capacitor identification
2 Attachment(s)
Hi all. I'm hoping some of the forum gurus who can identify caps on sight (and faster than a speeding bullet no less) can help me out with some new finds from the bargain bins. Anyone know the composition and/or sonic attributes of any of these caps?

From left to right:
0.33uF/250V, ??
5uF/100V, 2%, West-Cap WF70U1505
5uF/50V, 10%, TRW X663F
0.1uF/50V, 20%, TRW 8336

tiroth 5th June 2002 02:18 AM

2 Attachment(s)
Deep orange are Sprauge in sizes from .0082-.22uF, 80-200V, 10%
Yellow wrapped is Sprauge .047uF/100V, 5%

tiroth 5th June 2002 02:20 AM

2 Attachment(s)
From left to right:
2uF/200V, Aerovox P8292ZN14
0.1uF/200V, 1%, BEC 9637
0.15/50V, 5%, G.E.
Micamold and El-Menco. Anyone have a site for identifying values?

I also have some yellow film caps similar to Sprauge by IMB, Wesco, Aerovox, CDE, and "Acushnet Acu-cap. Several white film caps by STK, "MP900".

Thanks very much to anyone who can offer some input.

HarryHaller 5th June 2002 03:06 AM

Surplus caps
Most of the caps you find surplus are Mylar also know as metalized polyester. TRW is now ASC.

This might help to identify cap types also:

Alot of what a cap sounds like from construction rather than dielectric. IMB usally makes very good caps and the Sprauges and TRW are good caps also. You just have to listen to them. If you can find Electrocube brand caps they sound pretty good also.
European caps like Wima Rifa and ERO are also very good and are often marked for dielectric type:

MKT- metalized polyester
MKP- metalized polypropylene
MKC-metalized polycabonate

dice45 5th June 2002 11:11 PM


can help with the Mica colour code
(your 3rd pix, lower left corner. the brown square thing: El Menco, Cornell Dubilier, Sangamo, Aerovox or similar).

code has 6 dots, can be either RTMA or JAN or (ancient) RMA code.
Colours indicate same numbers , tolreances, multipliers as with resistor colour code of nowadays.
Capacitance is in picofarads (pF or F)
1st dot: white.
2nd dot: 1st digit
3rd dot: 2nd digit
4th dot: capacitor class (regarding Q, drift,insulation res. etc.)
5th dot: tolerance
6th dot: decimal multiplier

same as RTMA, but 1st dot is black and JAN standard instead of RTMA standards apply

1st dot: 1st digit
2nd dot: 2nd digit
3rd dot: 3rd digit
4th dot: voltage rating
5th dot: tolerance
6th dot: decimal multiplier

There exist also similar looking micas with rectanguar shape and 3 dots. They have 20% tolerance, 500V rating,
1st dot: 1st digit
2nd dot: 2nd digit
3rd dot: decimal multiplier

In case a a 4th corner dot is left above the 1st dot, this dot indicates tolerance.

For further info please consult the Radiotron Desinger's Handbook, 4th ed., pp1340.

Those ancient micas can be crap and also be extremely good. Before you rely on the voltage rating, measure each and any sample. They may go boom and take your cherished output tubes with them to Nirvana. SS use is uncritical, Best use: shunting PS electrolytics and coupling caps. Also use them for FB and phono EQ. but by any means, compare them to good polystyrenes or polyprops.

General hint (exception: PS) use micas in homoeopathic doses; you would not like overdosing sonically :)

HarryHaller 5th June 2002 11:35 PM

Mica colour code
YIKES!!!! This is why I own two capacitance meters.....

"use micas in homoeopathic doses" I love it, what an interestingly poetic analogy. I say we vote Dice45 as the DIYaudio poet laureat.


tiroth 6th June 2002 01:27 PM

Thanks for the help guys.

dice45 6th June 2002 03:56 PM


A poet reading his poetry in public may have other nastys habits.
(Robert.A.Heinlein, Notebooks of Lazarus Long)

HarryHaller 6th June 2002 05:19 PM

Lazurus Long
Hey! I read Time Enough For Love and Mr. Long has a LOT of nasty habits but at least building amps was not one of them. Your taste in sci-fi is very refined. Heinlien is the best, I just reread Strange in a Strange land.


dice45 7th June 2002 12:45 AM

Harry and all,
not only in sci-fi ... my taste is exquisite :) and expensive :)

concerning Heinlein, i am not that interrested in the sci-fi all too much albeit Heinlein's imagination is sometimes breathtaking. He manages however to depict utterly realistic fictionary societies of the future.
The moral philosophy underlying his stories is very much to my taste .... as the ethical values are .... and his definition of moral as group equivalent to survival instinct just hits.

Maureen Johnson from "to sail beyond the sunset" is an incredible and erotic female character ... love it. Most amazing: unconventional erotic athmosphere and moral philosophy do not disturb each other, quite opposite, very open-minded, just look at young Maureen's 10+6 commandmends.

I am not much of a democrat (German democracy turns out to be a gooey mess with a mighty minority dominating public opinion and even questioning election results, same with the US one ?), but the sort of democracy described in "Starship Troopers" really could work.

"stranger in a strange land" is a lil'bit overdone, not my taste.

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