[Boatanchors] capacitors

[Geoff]

----- Original Message ----- 
From: "Richard Knoppow" <1oldlens1 at ix.netcom.com>
To: "Boat Anchors Mailing List" <boatanchors at mailman.qth.net>; "Glenn Little 
WB4UIV" <glennmaillist at bellsouth.net>
Sent: Monday, February 13, 2012 11:22 AM
Subject: Re: [Boatanchors] capacitors


>
> ----- Original Message ----- 
> From: "Glenn Little WB4UIV" <glennmaillist at bellsouth.net>
> To: "Boat Anchors Mailing List"
> <boatanchors at mailman.qth.net>
> Sent: Sunday, February 12, 2012 10:15 PM
> Subject: [Boatanchors] capacitors
>
>
>>I recently got some capacitors at an estate sale.
>> There are some Cornell Dubilier PM602 and some GE MAL
>> molded
>> capacitor in the lot.
>> Are these in the same class as the Sprague BBOD?
>> They are both molded capacitors.
>> The GE capacitors are black and the CD capacitors are
>> green.
>> There were also some orange drops and brown dipped
>> capacitors in the lot.
>>
>> I plan to use the orange drops and the brown dipped
>> capacitors first.
>> Should I keep the GE and CD capacitors or find an audio
>> phool??
>>
>> Thanks
>> 73
>> Glenn
>> WB4UIV
>
>    Early Black Beauty caps seem to have had a production
> problem that caused them to fail after only a short time. I
> think that was a specific problem to this particular brand.
> However, all paper dielectric caps seem to have limited
> lives. The change from paper to cast or dipped plastic was
> supposed to eliminate part of the problem and extend the
> life but all old paper caps are suspect regardless of type
> of case or brand. Test any of these before using them. They
> may be just fine but just age may cause some problems.
> Curiously Sprague sold dipped caps which are described in
> the catalogues as having the same construction as the BB
> caps but they did not fail early.
>    Modern film capacitors are superior to the old paper
> caps even when they were new.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com


Based upon almost 5 decades of experience I disagree with a lot of that.

All BB's of paper cap construction and their cheaper OEM Bumblebee versions 
are defective no matter what year of production from the late 40's into the 
late 50's.

The same with all other manufacturers such as CD and Sangamo who all got 
into the act and there were even a few ceramic tube versions.

Sprague did have a premium BB that was a film construction and these are 
easily identified by the red graphics. I have tested many in 50's HP test 
equipment that are still perfect and Ive several NOS on hand that I feed to 
the audiophools on Fleabay at ridiculous bids.

While at National we were replacing several brands of sealed caps in sets 
that were not even 5 years old and this was in 1963 when I first joined the 
Service Dept. Replacements were dark brown and maroon radial Mylars that 
will still be good....at least I havent found a bad one yet plus I have 
hundreds purchased at the 1992 auction.

Carl
KM1H



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