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Old 06-20-2007, 04:48 PM   #1
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Join Date: Apr 2006
Location: North Texas
Posts: 5,429
Sprague Atoms

TFFer, JAM, pointed this out to me. But on a couple other amp boards, someone posted pics of Sprague Atom cut open. I think it started over at Hoffman's boards but it surfaced on Weber's, too. Apparently there's been talk of them being a little cap inside a big cap can.

I do know that Sprague announced that the manufacture of the Atoms had become obsolete. Now I understand why. Also why they're so expensive.

Someone then wondered if this was how they always made them. Someone posted one from '76 or '77.

The "problem" with Atoms is: they published the Sizes in the late 1940s/1950s, they must continue to make them THAT size or a few customers will whine, but the old fat paper/foil materials have been obsoleted and are no longer used. So you get a better cap, which is smaller, but they have to put it in an old-size can. The 50% excess space is for no electronic reason, it is just to give a mechanical "Exact Replacement".

So what you got is a newer better cap in an old-size can.

> are Sprague Atom caps being constructed/built/manufactured to the same specification that they used to be?

No. They can't get the old materials. New materials ARE better.

> have they taken short cuts, cuts that have affected long term reliability or even short term, cost actions that have put a reduced quality product into the hands of the consumer.

You forget how bad electrolytics were in the 1940s. The new ones ARE better. Reliable e-cap production is a very high-purity process and such manufacturing has come a long way since Atoms were introduced. (They once used raw borax; now it is all extra-refined electrolytes.) Early e-cap production used foil and paper much thicker than really needed, because they didn't have anything thinner; increased demand spurred right-thickness materials. If you think an old one "sounds" better, it is probably aging processes or just self-deception.

> Anybody have an OLD sprague they can dissect?

I had a couple of the Original 1930s Spragues. They came in a wax box instead of a can. The box held a turd just like seen above, just like any asian cap (except asians tend to use a lighter color paper). A 16uFd 450V turd was about 8 times the cubic volume of TubeGeek's 16/475 Atom, filled most of the box. They were utterly dead, and had probably been dead for a half-century.
Quite interesting.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."

-Edmund Burke
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