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Had a chat with an old radio guy that changed how I look at caps
I was picking up a vintage amp from a retired broadcast engineer in Portland, and he told me he never replaces electrolytic caps unless they're actually leaking or dead. He said he's seen too many perfectly good 50 year old units get wrecked by people shotgun replacing stuff. Has anyone else ever tested caps before swapping them, or do you just replace them on sight?
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paulw635mo ago
...and here I am with a soldering iron and a shotgun approach, probably the guy he's warning everyone about. I mean, to be fair, I've definitely ruined a perfectly good piece of gear by swapping caps that were still measuring fine on the meter. It's like I get nervous looking at old electrolytics, my brain just goes 'replace em all' without even testing. Maybe that retired engineer has a point though. I should probably dig out my multimeter and see if my vintage receiver actually needs a cap job or if I'm just looking for an excuse to break something else.
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jamienguyen5mo ago
Used to be the same way. Shotgun approach, replace everything. Then I ruined a perfectly functional 70s Marantz by swapping out some filter caps that were still within spec.
@paulw63 gets it, that feeling of "replace em all." But after that Marantz, I started testing first. Found an old Tektronix scope where most caps tested fine. Only swapped the three that were actually drifting. Kept the original sound intact.
Now I test everything. Takes longer but saves the gear.
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spencer_chen65mo ago
Man that Marantz story hits close to home. I did the same thing to a 1964 Fisher receiver about five years ago, replaced all the caps in the preamp section and it never sounded the same after. It lost that warm punchy character it had, ended up selling it for parts. Now I test every single cap with my ESR meter before making any moves. It takes forever but at least I know what I'm actually dealing with. The old broadcast guy is right, these vintage units have a certain lived in sound that you can't get back once you start swapping out parts that are still good.
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