Changing Inductance

[Roushon]

I purchased a 10mH inductor for a crossover network from madisound speakers.

https://www.madisound.com/store/product_info.php?manufacturers_id=139&products_id=857

But I need to change it to a 9mH. How many turn of the coil should I remove?
I do not have a meter to check the inductance. Thanks in advance.

Regards
Roushon.

 

[pheonix358]

As far as I am aware the only way to do this is with a meter.

 

[Elvee]

You could try to "guesstimate" the number of turns by multiplying the number visible on the outer layer by the number of layers.
You then remove 5% of that quantity. Won't be very accurate, but anyway, a change of 10% for such a coil is rather cosmetic.
Some cheap techniques to measure inductors have been described in the ZLCR thread, here:
http://www.diyaudio.com/forums/software-tools/173248-awesome-zlcr-meter.html

 

[Roushon]

You could try to "guesstimate" the number of turns by multiplying the number visible on the outer layer by the number of layers.
You then remove 5% of that quantity. Won't be very accurate, but anyway, a change of 10% for such a coil is rather cosmetic.
Some cheap techniques to measure inductors have been described in the ZLCR thread, here:
http://www.diyaudio.com/forums/software-tools/173248-awesome-zlcr-meter.html

I will try your suggestion. I read somewhere that in crossover parts 5% tolerance is
acceptable. If 10% is also OK then I do not have to change the 10mH. I can use it
in place of 9mH which I am doing at present and wanted to try with the correct
value.

Thanks for the interesting ZLCR thread.

Roushon

 

[Roushon]

Finally changed...

Purchased an inductance meter and finally unwrapped
some part of the inductor to reduce its value to 9mH.

Roushon

 

[Roushon]

The sound considerably improved. The woofer is
more active now and I hear more clear bass than before.
So it does make a difference to be accurate in the
inductance reading.

Roushon.

 

[picowallspeaker]

Thanks for sharing