Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Packerswin14 on February 06, 2016, 11:29:34 am
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I got these vintage capacitors in a chest full of old parts at a yard sale. I'm having trouble decoding them, because the usual color chart produces odd voltages like 900v, tolerances like 4%, and .values like 0008, etc. Some have 5 bands, some 4, and some only 3. Does anyone recognize these or have insight into what the values are? I'd like to find some use for them and not just landfill them because I'm ignorant of their specs.
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they look quite thin and small, so i would guess somewhere in the nF pF range. ceramic perhaps?
if you know someone who can measure the value you might find the clue to the color code.
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same color code as resistors.
http://www.electronicshub.org/capacitor-color-codes/ (http://www.electronicshub.org/capacitor-color-codes/)
--pete
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I am not sure if these are the caps called "tropical fish" A quick search for "capacitor tropical fish", shows pictures of the Mullard/phillips C280 caps which are considerably more colorful. On the web, there is at least one color code for the Mullards assuming they are mullards.
Your caps are unusual, so they may be worth something.
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I'm not sure, maybe a vintage capacitor checker could get an accurate read? My modern capacitance meters don't give me any result at all. Clearly the resistor color coding isn't the whole story-- you should re-read the entire post if you think the standard resistor color coding fits for these caps. I doubt they were producing resistors with 4 or 9% tolerance, or odd values. Vintage stuff usually follows the common values- 47's, 22's, 82's, etc.
drgonzonm
you're right, these aren't the typical tropical fish caps, but that's the closest type I've ever seen. The really short leads on these make them appear to be built for circuit boards, but the design, paint, etc. makes them look more like 1940's-50's. No good clues from the other stuff in the parts chest-- about 25 modern small inductors, a bunch of modern transistors, about half of which were good and half were used and pulled because they are bad (who saves bad transistors?), a few IC's, and then just a few other vintage-looking parts, and oh, yes, a rusty needle my wife stepped on (she was not happy, fortunately her tetanus booster was still good).
If anyone else has any insight, I'd still appreciate any clues you can give, either as to how to read the odd color coding, or any info about brand, purpose, or circuits you may have seen these in before.
I admit my vintage electronics knowledge is pretty limited, I've mostly only worked on vintage tube amps and some tube radios. I helped grandpa with some antique truck restos back in the day, but those have very little in the way of electronics inside.
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if you look at the color coding like resistor codes, say one is 15K, that might mean 15,000 pf? Which *counts furiously on fingers* gives you an .015... I think.
You probably already know this, but to measure small caps I find it's better to use clips on the leads. Your body screws up the reading if you're holding them on there with your fingers.
Be warned, I might be completely wrong with all of this!
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No, that is helpful, John. You're right, especially at these small capacitance numbers, contact with your hand does mess with the readings, but I still can't get it to show give me a reading. And .015 is not super common, but at least believable. That would indicate that these caps have no given tolerance or voltage markings. So I could then half-assume that the ones with only 3 bands have no multiplier.
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Those look like small coils. These are probably in the microHenry range. Used in TV sets, rarely in audio amps.
Look at the other side and see if you see a circular looking lump. That would be the actual coil of wire.
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Your third one, is plausibly an "022" or "220" which is frustratingly ambiguous.
I am not entirely convinced those are caps. I suspect they are little RF chokes. Frankly, if your meter says they are not caps, they ain't, no matter what the color code is.
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A coil will have 1 to 500 Ohms. A cap should be near infinity Ohms.