M5B coil inductor in crossover

Jockos

Apparently the solder connection in my 5B crossover failed. The copper wire inductor that goes to the printed CB broke free. I did manage to solder it back. However when it broke the copper windings came undone. I did the best to wind it around the plastic spool. I have some questions; will this affect performance and exactly what does a wire inductor do? Should I get a new crossover? And if I do need a new crossover do I need to get 2 since it is quite dated.

Thanks for any help
Jocks

heiney9

Yes, the inductor is an important part of the x-over. Having it come unraveled is not a good thing. See link for an indepth desc of an inductor.

http://en.wikipedia.org/wiki/Inductor

The bad news is Polk no longer makes replacement x-over for the Original Monitor series. The good news is by looking here

http://www.polkaudio.com/forums/attachment.php?attachmentid=14948&d=1142111790

you can see in the schematic the inductor's are 1.55 mH for the midbass driver and 0.23 mH for the tweeter and I believe you can buy an exact replacement and solder it in yourself. It may not phyiscally look identical but as long as the rating and construction are the same you should be fine. For more specifics contact Ken at Polk Customer Service

Look here for parts

www.partsexpress.com

Hope this helps

H9

Jockos

Thanks heiney9 for the info. I went to the parts express site but I'm fairly confused, I guess the inductors come in different gauges and the ohms are different. I saw on the polk parts website that they might still have a couple of crossovers in stock, or maybe they can repair it. Hopefully Ken S. can post some info.

Jockos

F1nut

Jockos, rather than wait for Ken to respond here, call him.

heiney9

F1nut wrote:

Jockos, rather than wait for Ken to respond here, call him.

Yes, call him he's very easy to talk to and very helpful. I've never had need to buy inductors so I can't be of anymore help. I doubt the Polk x-over's are still avail, but you might get lucky.

H9

jcaut

I believe that if you can wind the wire back around the bobbin-- maybe not too easy if it all came unwound-- then put a piece of electrical tape around it to hold it, you'll be fine.

Yes, the winding technique and tightness does make some difference, but it would be minimal, IMO.

But, yes, talk to Ken. I'm sure he'll be able to help.

Jason

P.S.: To answer your question about what an inductor does: Inductors have a DC resistance (just like a resistor) that depends on the size of the wire used, and on the size of the inductor (bigger inductor=more wire, generally). They also have inductive reactance that causes the impedence of the inductor to increase as the frequency of the signal passing through it increases. They're usually used in series with a woofer, to filter out high frequencies the woofer shouldn't reproduce, or in parallel with (shunted across) a tweeter to provide a low impendance "return path" for the low frequencies that don't need to reach the tweeter. The DCR is important in the circuits, too, and therefore it is listed for replacement inductors. That's also the reason you shouldn't substitute an inductor of different wire gauge or construction, unless you know what you're doing.

[Deleted User]

Hello,
I'm pretty sure I can find a replacement inductor to send you. Give me a call at 1-800-377-7655 extension 891 or email me at kswauger@polkaudio.com and we can compare notes.
Regards, Ken

Jockos

Just got off the line with Ken S. He's going to find a spare inductor for me. Once again great customer service. Thats why I've been a polk customer for 20 years and have had over 12 different polk speakers.

Thanks and aloha

Jockos

[Deleted User]

Hello Jockos,
I found a coil and measured the inductance. As you are aware it is wrapped around the 6.5" plastic input plate. This would involve you removing the binding post and installing them into this replacement, then unsolder the positive and negative wires from the crossover network and solder in the new inductor and ground return wire. If you want to send the crossover to me I can replace the inductor for you, at no charge. Or, I can send the part to the address you've given me. Just let me know.
Regards, Ken

F1nut

Ken, THE MAN!!!

Jockos

Ken,

Thanks for all the help, I'd rather send the crossover to you since I don't trust my soldering skills all that much. Let me know the address and Ill send it to you.

Aloha,

Jockos

[Deleted User]

Hello Jockos,
No problem, you would send it to: Polk Audio, 5601 Metro Drive, Baltimore, MD. 21215, attn: Ken.
Thanks, Ken

Jockos

On it's way Ken.

Thanks,

Jockos

[Deleted User]

Hello Jockos,
I received your crossover today, I should be able to repair it over the weekend.
Take care, Ken

[Deleted User]

Hello Jockos,
The crossover repair went well, I replaced the inductor and tested the high and low pass sections of the crossover. It seems fine, I'll send it out today. Thanks for the chocolate treat! I'll share them with everyone here at Polk.
Take care, Ken

Jockos

Ken,

I can't thank you enough for helping me out; if you're ever in the area drop me a line, I'll be more than happy to show you around.

Thanks and Aloha,

Jockos