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"Capacitor off value" record?


KlausDK

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I am fiddling with a set of unrestored, late version AR-11B (from 1978), and took out the 10 uF tweeter cap for replacement (it is the black Callins? with the red sealing in the ends). Just out of interest, I tested the value on my multi meter, and this must be a record in capacitor off value: 32 uF! I just need an 8 uF in parallel and I can use it for the midrange.

BRgds Klaus

post-101646-1210498401.jpg

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I am fiddling with a set of unrestored, late version AR-11B (from 1978), and took out the 10 uF tweeter cap for replacement (it is the black Callins? with the red sealing in the ends). Just out of interest, I tested the value on my multi meter, and this must be a record in capacitor off value: 32 uF! I just need an 8 uF in parallel and I can use it for the midrange.

BRgds Klaus

Careful Klaus. That Calluns' ESR may also be way off. Did you test that also? Just adding the parallel cap may bring the crossover point back to spec, but the mid's potential output may suffer due to elevated impedance across the caps.

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Careful Klaus. That Calluns' ESR may also be way off. Did you test that also? Just adding the parallel cap may bring the crossover point back to spec, but the mid's potential output may suffer due to elevated impedance across the caps.

Hi Carl

Sorry, I was just being ironical, a Danish folk-art not always easily applicable to other cultures, maybe except the Brittish. I cannot measure ESR, unfortunately. but rest assured, I have no intensions of using the cap for anything else than another addition to the horror cabinet.

BRgds Klaus

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...another addition to the horror cabinet.

A lot of those old Callins belong in a cabinet of horror.

It's all part of a vast left-wing, liberal Massachusetts' conspiracy to slowly ruin the expensive speakers of the vast right-wing conspirators, who, being conservative, conserve things for long periods of time. There's some Cabot / Lodge / Kennedy-thing going on... skimping on bridge widths and not-watering the booze... It isn't pretty.

Thanks for reminding us once again that those red-capped black tubular things don't even rate a decent burial.

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  • 12 years later...
10 minutes ago, KlausDK said:

Just a friendly reminder, whenever you see those black Callins in you AR speaker, GET THEM OUT!!! 😬
6 uF cap. measures 27.8 uF, poor tweeter!!

20210108_152219.jpg

Well done for updating and reminding all of the importance of this. 🙂👍

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Yes ... those 6uF seem to be particularly awful.  You'll see in the attached image that one of the ones I removed from my AR-9's measured 77uF at 1KHz - 1,180 percent of its nominal value!  The other one was only 31uF, 416% of nominal.  Getting the correct values in the crossovers certainly makes a significant and audible difference!

Removed Parts - AR9s.jpg

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I'd toss that old callins for a modern cap. When I recapped my 90s I found several were still within range (+/- 10%) BUT sounded horrible. I thought my tweeters had dried ferro-fluid.  The tweeters are fine. The old callins caps were acting more as a resistor than a capacitor.

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