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Caps that last 50 years? All you need is a time machine.

nomadradio

Analog Retentive
Apr 3, 2005
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Louisville, KY
www.nomadradio.com
This set of filter caps came out of a Drake L4B power supply. Took them nearly 50 years to go bad. Yes the date code really is from 1973.

gd8I5C.jpg


The upgrade used a modern double-sided printed circuit board with snap-in filter caps and rectifiers. All on one board. The one in the pic is only half the original setup. One board like this on each end of the cabinet is what went in at the factory in 1973 or 74.

Got to thinking about how long it takes to find out what kind of service life a component can deliver. In this case, nearly fifty years. Definitely better than average.

But by the time you find out what lasts a long time and what doesn't, it's too late to take advantage in any way.

Can draw only one conclusion. All you really need is a time machine. Go back and fetch a case of these.

Odds are they would outlive you and me, both once they're installed. This is not the first Drake L4-PS we have seen with caps that still work after almost 50 years.

Just one problem. You'll get pestered to also bring back some 8908, 2057, 8950 tubes and such. Gotta figure every time machine has a load limit, so this could be a dilemma.

Just one piece of advice before you go. Check the dates on your cash first. Wouldn't want to get locked up in 1973 for counterfeiting and not be able to come back.

73
 

Just one piece of advice before you go. Check the dates on your cash first. Wouldn't want to get locked up in 1973 for counterfeiting and not be able to come back.

And slim chance they'll take PayPal..........
 
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Do you think that these caps were exceptional; or survived because they had optimal conditions? You know; even environment, kept cool, and weren't abused? How did these caps survive and what did the mfr do to get them to be right.
 
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Ok let's see here first things first I will need to find a DeLorean that still runs & can get going 88mph (142km/h) in a short distance.
 
This set of filter caps came out of a Drake L4B power supply. Took them nearly 50 years to go bad. Yes the date code really is from 1973.

gd8I5C.jpg


The upgrade used a modern double-sided printed circuit board with snap-in filter caps and rectifiers. All on one board. The one in the pic is only half the original setup. One board like this on each end of the cabinet is what went in at the factory in 1973 or 74.

Got to thinking about how long it takes to find out what kind of service life a component can deliver. In this case, nearly fifty years. Definitely better than average.

But by the time you find out what lasts a long time and what doesn't, it's too late to take advantage in any way.

Can draw only one conclusion. All you really need is a time machine. Go back and fetch a case of these.

Odds are they would outlive you and me, both once they're installed. This is not the first Drake L4-PS we have seen with caps that still work after almost 50 years.

Just one problem. You'll get pestered to also bring back some 8908, 2057, 8950 tubes and such. Gotta figure every time machine has a load limit, so this could be a dilemma.

Just one piece of advice before you go. Check the dates on your cash first. Wouldn't want to get locked up in 1973 for counterfeiting and not be able to come back.

73
 
Mouser Electronics still had a version that was enclosed in a plastic case last I checked. 24 Volt DC coil, 3PDT 10 Amp contacts. The original open-frame type relay has indeed become scarcer by the year.

If customer traffic slacks off I'll track down their stock number tomorrow and post it. Not feeling ambitious enough to wade into their online catalog tonight.

73
 
Last edited:
Do you think that these caps were exceptional; or survived because they had optimal conditions? You know; even environment, kept cool, and weren't abused? How did these caps survive and what did the mfr do to get them to be right.
It's probably a combination of both high-quality capacitors and optimal conditions. That particular brand name of capacitors, was noted as being high quality.
 

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