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Re: Sprague capacitors variants

 
Edited

Don
The text in the first ad you found says that the TM (Tubular Molded?) says that it has been in development for 4 years.? That puts it at the end of WW2.? Printed values and logo, no stripes, so I'm not sure that the TM was ready for prime time.? Same as seen in your second ad.

The earliest ad that I found for the first generation Black Beauties is September, 1948 in "Electronics," paper page 58, pdf page 62.? Still not called Black Beauty but the value is shown in color coded color stripes.


A more detailed ad is in "Electronics," July, 1950, paper page 119.? Still not called Black Beauty, it is referred to as a molded tubular, with color stripes, as it is in the above ad.

Found an ad in "Electronics,"?January, 1956 on paper page 11,?calling the molded tubular capacitor a Black Beauty,?

I will search the jobber magazines for the Black Beauty trade name but I suspect that the equipment designers got their ideas from the more technical pubs like "Electronics."? If anyone finds a Black Beauty ad before 1955, give a holler.

Regards,
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy


On Monday, April 29, 2024 at 04:45:19 PM CDT, don Root <drootofallevil@...> wrote:


Richard, also Jacques and all

re¡­..The early one does not list any molded paper caps

Here is the first ad I found for the molded caps , no telecap or black beauty yet

??? ?

^^ 1948-02? Radio-Maintenance-

pdf? 21 ---

?

¡­and the first telecap ad

? ?

^^? 1949-04 RSD-

Pdf?? 12 ?

?

?

?

And telecaps are referred to by the expression ?[These "Black Beauties"] ??

^^ 1950-04 Radio-News-

pdf?? 16??? -----??

?

then two month later? =? Sprague Black Beauty Telecap? Tubulars ??

?????????? ????

^^?? 1950-06 Radio-Maintenance-

pdf???? 4? -----? ?

?

?

RE ?In any case, I believe these are the replacements for the Black Beauty caps

I don¡¯t understand this. ???Black Beauty began in 1950, and ran in ads to 1967. but the construction changed first brought in HCX and later Difilm ?

?

From: [email protected] [mailto:[email protected]] On Behalf Of Richard Knoppow
Sent: Sunday, April 28, 2024 10:42 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] Sprague capacitors variants

?

FWIW, I have a couple of hard copy "Radio's Master" catalogues.
Others are on the worldradiohistory.org site. The ones I have are 1947
and 1953. The early one does not list any molded paper caps, the 1953
edition shows Sprague Telecap, called Black Beauty in quotes but without
RMA code striping. These are described as "dry process" caps with the
same qualities as oil filled ones. In any case, I believe these are the
replacements for the Black Beauty caps. I am too lazy to look at the
on-line catalogues but, from memory, it seems to me that BB was used as
a trademark about 1950.
The 1953 catalog also shows Sprague Vitamin-Q caps.
Some older Hewlett-Packard instruments, like early 400D and similar,
have molded sprague caps with RMA coding on them. These do not seem to
have failed and don't show the mechanical disintegration of the caps in
the Hammarlund receivers. I don't know if they are the same caps or not.
The signal corps issued modification work orders to replace all
paper caps in the SP-600 about the mid 1950's, I don't know the exact
date. The caps were replaced with disc ceramic types.
The Black Beauty caps were advertised as "deluxe quality at no
higher price" for use in locations with high heat. Telecaps were
advertised for similar applications especially, as the name implies, in
television sets. Other manufacturers made similar molded caps, for
instance, Cornell-Dublier made Blue Cubs. Paper caps of all types have
limited lives but the Black Beauty seems to have had a special problem.
On 3/25/2024 1:17 PM, Richard Knoppow wrote:

Sprague began using the trade name "Telecap" after the Black Beauty
was discontinued. I don't know for certain but think they were the same
capacitor with whatever was wrong fixed. These look like their
advertising illustrations, no stripes, values marked in numerals. Again,
I don't know the exact dates but think the BB problems happened about
the mid or late 1950s.

On 3/25/2024 11:43 AM, Jacques_VE2JFE wrote:

Hi all, I still had, until recently, few ¡°Bumblebee-coded¡± 0.01?F, 600V
Sprague capacitors that passed all the leakage tests with flying colors.

--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998


--
don??? va3drl

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