[mike noble]

I am going to build the Martin J King passive two way O/B but am having trouble finding a 30 mH inductor for the bass driver xover, does anyone out there know of a supplier, UK ? I have used a number of on line calculators for the xover and none have come up with a 30 mH inductor.
Would using a different combination of capacitor and inductor for the bass unit have an effect on the performance of the Fostex xover, and alter
the sound.
Is it practical to use two lower value inductors in series to make up the 30 mH inductor.
I would be grateful for any advice, but not to technical please.
Thanks
Mike Noble

[JerryM]

Welcome to AudioCirlce, Mike. 

[Guy 13]

A warm welcome to AudioCircle Mr. Mike.

Guy 13

[FullRangeMan]

I am going to build the Martin J King passive two way O/B but am having trouble finding a 30 mH inductor for the bass driver xover, does anyone out there know of a supplier, UK ? I have used a number of on line calculators for the xover and none have come up with a 30 mH inductor.
Would using a different combination of capacitor and inductor for the bass unit have an effect on the performance of the Fostex xover, and alter
the sound.
Is it practical to use two lower value inductors in series to make up the 30 mH inductor.
I would be grateful for any advice, but not to technical please.
Thanks
Mike Noble

I unknow this project but it seems unsual, 30mH will cut around 40Hz.
Maybe it is 3.0mH(cut around 400Hz) in this case you would contact Jeff at Sonic Craft very friendly service.

If 2.9mH(cut around 430Hz) fit yours needs Sonic Craft price are nice:
http://www.soniccraft.com/product_info.php/pair-alpha-core-16-awg-290mh-p-5092

[mcgsxr]

Welcome to AC, and thanks for your interest in OB!

We have a "special place" for folks like us here, so future questions might get answers in our OB Circle.

http://www.audiocircle.com/index.php?board=90.0

[Phil A]

Welcome to AC!

[planet10]

Where did you get 30 mH? We built based on the original article (but with FF85k) which specified 9 mH, worked fine. I see in part 2 he is now specifing 5 mH.

Do note that in his table in Part 2 he has the units uF & mH switched. There is a 30 uF cap.

dave

[planet10]

I sent Martin a message about the swapping of the units on his table… he wrote back suggesting he needs to recheck the values of his LP filter as well, so you might want to postpone buying components.

dave

[planet10]

Martin has fixed the mistake in part 2 and it can now be downloaded.

http://www.quarter-wave.com/OBs/OB_Design_Part_2.pdf

You are now looking for a 9 mH choke.

dave

[mike noble]

Thanks for advice re crossovers, unfortunately already ordered bits. have looked at part 2 on link, still the same as my original download with wrong figures. I will just go with crossover for alpha 15 from part 1 and use part 2 for FF125WK.

[ArthurDent]

Greetings & Welcome to AC mike