What is this inductor value

[bumpy]

This may be asking the impossible, but you don't know till you try :)

I have a pair of these inductors taken from a vintage pair of Rogers speakers. I have no way to measure their values - all I have is that the resistance is about 0.5 ohms, the copper winding about 1.4mm and the weight of each is 450g. The central square former is plastic/ Bakelite.

Would anybody like to hazard a guess at the value.

If its totally impossible to guess, please say so. This will stop me waiting on answers.

Thanks

Chris

[Firebottle]

Could make a stab at it if the number of turns were known.

Or 2 seconds to read the value on my LCR meter.

[Lawrence001]

Or tell us which model they're from and we might be able to work it out from available schematics.

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[bumpy]

Alan
I didn't know there was a simple meter that could make this measurement. Everything I read suggested I needed an oscilloscope :( Found LCR meter at less than £25 so its on my borthday list.

Lawrence
Inspired by your post I went out to the shed to see if I could make out the model number on the old stripped Radford cabinets I stored there. And then a magic moment - when I found the crossover circuit diagram on a metal plate. The main driver was a KEF B139 with inductor of value 2mH.

So, mystery solved. Thanks for your help.

[Lawrence001]

Great news. I wonder if that's the same inductor value as in the B139 filter in the Kef Concerto crossover you can get from Falcon.

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[Lawrence001]

It seems the Concerto also had a 2mH inductor as I suspected. Interestingly there was a later concerto crossover that used a 4mH inductor.

https://www.falconacoustics.co.uk/kef-concerto-33mc-falcon-super-power-upgrade.html


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