S75, The worst crossover I've found

33 replies

Hello everyone,

I purchased a pair of S75's about six months ago and have more than happy with them. Upon further inspection however, I noticed that one of the midrange speakers was not working. Set up with a 5.1 system it was difficult to hear the absence unless you were close to the speaker so it didn't bother me. I recently got a moment to open it up in attempt to locate the culprit. Let's just say it was quite obvious (see photos below). After opening it up, the woofer wire fell apart. It amazes me that any sound came out of any of the 4 speakers. After a few hours of google image searching, on the spectrum of "light toast" to "your toaster melted", I fell as though I landed the latter. I opened the other speaker for comparison and to make sure it wasn't in need of some major TLC as well (pictured below). Thankfully it looks brand new. I will likely order two of all replacement parts and repair both crossovers to the same specifications for continuity.

My question is in regard to the inductors. I was originally going to ask about specifications for the capacitors and resistors but was able to locate a schematic with the values (included below). The schematic does leave some information out about the inductors. As you can see in the photos, I do not think it is a good idea to replace everything and leave the charred inductors in there.

The schematics state that the most heavily charred inductor has a specification of 0.26mH and has a ferrite core. Looking primarily on Parts Express but also some google searches, 0.26mH inductors are difficult to find. 0.25mH and 0.27mH inductors are plentiful. I also noticed that with differences in wire gauge comes differences in Ohms. Is there a way to tell, or does anyone know what gauge wire these inductors have or their original Ohm rating? Would using a 0.25 or 0.27mH inductor make much of a difference?

If the seemingly infamous "Martin (Dillen)" or someone similar stumbles upon this, they are Type 6313.

Any help is greatly appreciated.

 

link

Woops, charred one is 0.7mH. The above question still stands though.

Dont rely on the schematics and the component list, mostly the crossovers are different so where possible check the values on the crossover component and get new ones as close as you can get, as for the coils wait for Martin, or send him a mail

Location: Mexico city

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Oh dear, what a mess. Looks like one speaker was at a party, while the other stayed home.

Are the coils charred too? Maybe it's just my monitor, but I cannot see where.
Isn't it just a matter of cleaning the leads that goes to the coils where they've passed through hot areas ?

Martin

Here is a better image to show the inductor. Strange too that it's the only one that I have found that is purple. Looks like it took quite a bit of heat. Any idea of the specifications on these little buggers?link

Doesn't look too bad, if you ask me.
The color is fine and it was submerged in lacquer to prevent rattling and copper wire insulation breakup.
They are very sturdy components. I wouldn't suspect it.

Martin

Correct me if I'm wrong, but an inductor is just a loop of wire. I would check it for continuity. If it checks good, then it's probably OK.

I have seen burned out inductors before, but on power supplies. From EE-101, the voltage across an inductor is the inductance times the rate of change in current. If the current is interrupted, you can get very high voltages which may cause it to fail. Inductors can have pretty big tolerances, sometimes +- 50%. An exact match, such as 0.26 mH may not always necessary. But in audio it may be different, so my opinion should be taken with a grain of salt.

Location: Los Angeles, CA

andyjsegal wrote:

Here is a better image to show the inductor. Strange too that it's the only one that I have found that is purple. Looks like it took quite a bit of heat. Any idea of the specifications on these little buggers?link

 

Maybe you could compare measure coils between speakers if there is difference? If not, they are probably ok.

Did you get my email ?

Martin

I'm with Martin - a few of my projects had inductors (and resistors) that looked bad, but weren't.  They should be fine.

But, if you ever need an odd-valued inductor,

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