Infinity crossover coil value

I had a customer bring in an Infinity KPX00 crossover for a 6.5" car unit. Coil L2 has burnt marks on it, Its a 24db linkquitz riley filter (or so the spec sheet says). Customer claims low tweeter output

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in: (+)

-------| | == C=15.7ufd | C=14ufd R=(1,2,4) OUTPUT |------------][------------/\/\/\/\/\------| > | >L2 (burnt) | > * (tweeter) | * | |

------------------------------------------------ (-) (-)

So, the input is a series cap inductor combination with a 15.7 MFD and unknown coil in series with the amp. The center tap of the two feeds a

14MFD cap and then goes through a series resistor adjustable pad to the tweeter. I tried to read the coil on my sencore, and it measures about .3 MH. It won't pass any ring test (air core) so i know turns are shorted and this value is suspect. Any clue on the value of this coil?

Strange, this seems to be a 3rd order filter rather than what the tear sheets says. Only one coil on the high pass with two caps. Minus the pad, it looks like the 3rd order 18 DB filter here:

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and these calculated 3500hz values are (4 ohm nominal) C=7.5 ufd L=0.1364 mh C2=22.7

standard replacement coil values are .1,.13,.15,.20,.27,.33 and etc.

Thoughts?

Bob

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Reply to
BOB Urz
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You can't measure (or observe) the one on the other side?

Reply to
Richard Crowley

While not quite symmetric, the other channels crossovers coil is burnt worse than the one i am looking at now. So, no chance for a good part measurement.

Bob

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Reply to
BOB Urz

How badly burnt?

I've seen some pretty ugly messes based on an heavy-gauge wire choke that was still OK.

For openers, unless they were burnt open or fused, I'd measure both coils and see if they still measure the same.

On a really bad day, wind up a coil of the same gauge wire and same number of turns in the same form factor and measure it.

Reply to
Arny Krueger

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I would be rather concerned about what actually caused the inductor/s to be cooked so badly. Assuming you managed to replace them and get it going again, what's to say that the owner is not going to repeat the exercise?

He would have to be driving these things extremely hard to cause the burnouts so perhaps they are not matched to his amps power output and speakers correctly or he is running both amp and speakers into severe overload. In this case I would suspect that the speakers aren't in too good a shape either.

Reply to
Ross Herbert

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The drivers are intact. Yes, i believe they were driven hard. But i am not the sound police. Only the repair man. So he wants the crossovers fixed and i will fix them if i can. But if he fry's them again its on his dime. I didn't design them and did not overdrive them.

Bob

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Reply to
BOB Urz

Given unlimited time and doing it for the sake of doing it, the coil could be rewound by determining the size of wire, buying a spool, counting the turns of the old coil and trying to duplicate it.

Its an exercise in wasting a lot of time. I just need to get a value and throw in another coil. Preferably, of a bigger wire size so it might be more robust. (my guess is 20g on this one)

When i can get no rings out of them on the sencore, you can about guarantee some turns are shorted.

Bob

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Reply to
BOB Urz

I entirely agree Bob. I was trying to intimate that perhaps along with carrying out the wishes of the owner to repair these things, that a little education might be needed to avoid a repeat. If he doesn't want to heed your warnings, then sure, repair them as often as needed - it's his money he's burning.

The only caution with this procedure may be that when his speakers (or the amps) eventually do clap out he may try to blame you for their demise by saying you can't possibly have repaired the x-overs correctly because they hadn't died at the time the x-over first failed, so why should they have died after you repaired them. You can't reason with some people.

Reply to
Ross Herbert

That appears to be self-contradictory.

Are you trying to saythat even though the coils pass a shorted-turn test, you still think they are too far gone to be worth measuring?

Reply to
Arny Krueger

You DON'T understand Arny. Rings are GOOD on the sencore test. Low ring count or NO ring count means the coil is shorted.

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This coil would show NO rings on the inductor ring test. Its shorted. If its shorted, the measured value of inductance is not going to be accurate.

The ultimate solution is use the crossover circuit topography with the listed value of caps and known crossover point (3500hz) and use algebra to solve for the inductor value (solve for one unknown). I have been too busy to try to figure that out. I also don't know why the tear sheets says its a 24db filter, when the hand drawn schematic from the crossover does not show that. It would need another inductor for that. With two caps and a inductor, it appears to be a 3rd order.

I have barely a few hours in the shop before i have to head off to set up for Jeff Daniel's and do FOH sound for two shows today.

Maybe someone with a lot of time on there hands can ID the filter from the ascii drawing, and find the math to reverse engineer the inductor value. There's a challenge for you Arny if your up to it.

I am guessing its in the .13 range at this point.

Bob

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Reply to
Bob Urz

Consider that the speaker driver acoustic roll off may supply one pole.

Reply to
Speedskater

Right Bob I can't read your mind. You wrote a post in a way that would only be meaningful to someone who had experience with a specific piece of fairly esoteric test equipment.

Reply to
Arny Krueger

Just because most people have never heard of it, doesn't make it esoteric! Now an Agilent E4980A LCR Meter at $15,000 that's esoteric.

Reply to
Speedskater

Well , lets see. I said i got no rings, and that about guarantees a shorted turns. You (who obviously doesn't know about ringers), says it appears to be contradictory. So, you obviously thought you knew something about ringers to make your statement "that appears to be self contradictory". If you did no know what a ringer or ring test on a coil was, goggle was a few key strokes away.

The proper response would have been, I don't know about how ring tests work. Can you tell me how or supply a link? (which i eventually did). I am milady surprise with your wide knowledge base you did not know how a basic piece of electronic test gear works

I see you have not took up my challenge to reverse engineer the coils values. Guess your not up for a challenge today.

bob

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Reply to
Bob Urz

I know that this will make your day Bob, but I've never heard of a shorted-turn tester called a ringer. I said that the usage appeared to be contrdictory for that reason.

Therefore your claim that I thought I knew what a ringer was is completely false.

I just googled "ringer shorted turn" and nothing popped up that was obviously relevant in the first few pages.

Ditto for "ring test".

Reply to
Arny Krueger

Humm Arny, your not as smart as i thought.

Google Marco search: terms( coil ring test) Results 11 - 20 of about 1,190,000 for coil ring test.

Lets limit it down, add sencore

Results 1 - 10 of about 330 for coil ring sencore. (0.19 seconds) ePanorama.net :: View topic - Infinity crossover coil value

or

Results 1 - 10 of about 349 for coil ringer sencore.

First rule of web searches is to play with the search terms until you get the desired result.

Bob

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Reply to
Bob Urz

Which assumes you know what the desired result is. Arny was gracious enough to admit he had never heard of a ring test, therefore could not be expected to know. Now that may be surprising, but hardly a hanging offence. :-)

MrT.

Reply to
Mr.T

Not what I said. I introduced a concept that seems foreign to you Bob - hits that are actually relevant to the topic.

By citing all these irrelevant hits, you're showing that you can't determine relevance of the hits received to your own topic.

Reply to
Arny Krueger

You've got to remember that Bob is a disciple of the inestimable Phildo and George, the bitter, often intoxicated trolls who continuously run down AAPLS.

Reply to
Arny Krueger

Ok Arny. Your a smart guy RIght? You have used google before right? And you know how to search for topics?

With the words "coil ring sencore", here are the hits (in order)

ePanorama.net :: View topic - Infinity crossover coil value to the tweeter. I tried to read the coil on my sencore, and it measures about .3 MH. It won't pass any ring test (air core) so i know turns are ...

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- 69k - Jan 20, 2007 - Cached - Similar pages [PDF] Complete Flyback/IHVT Testing File Format: PDF/Adobe Acrobat - View as HTML secondary windings will never ring 10. The primary coil is usually the ... This can be tested with a Sencore Z-. Meter. You first need to find two separate ...

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- Similar pages Sencore designs, builds, and markets electronic test instruments. Sencore designs and manufactures electronic equipment for service and repair ... number of cycles the inductor rings before reaching a preset damping point. ...
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- 15k - Cached - Similar pages [ More results from
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] Sencore Sencore, Inc. >Test Equipment / AC Power Management > General or Systemic ... all four failure modes, and complete coil tests for value and shorted turns. ... catalogs.infocommiq.com/AVCAT/CTL1857/index.cfm?mlc_id=1857&NOTRACK=1&pin_id=2345&prodID=315911

- 23k - Cached - Similar pages [PDF] LC103 ReZolver In-Circuit Capacitor & Inductor Analyzer File Format: PDF/Adobe Acrobat - View as HTML Sencore Engineers have. empirically determined that any air core. or ferrite core coil will ring at least. 10 times before decaying to less than 25%, ... catalogs.infocommiq.com/AVCAT/images/documents/pdfs/LC103%20brochure-6956.pdf

- Similar pages Method and apparatus for testing television yokes and flyback ... Assignee:, Sencore, Inc. (Sioux Falls, SD). Primary Class: ... Each capacitor will cause the coil 16 to ring at a different frequency. ...

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- 26k - Cached - Similar pages Sci.Electronics.Repair FAQ: Testing of Flyback (LOPT) Transformers Another 10 turn coil is wound on the suspect flyback core anywhere it will fit. ... Sencore and others sell test equipment that includes the 'ring test' or ...
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- 54k - Cached - Similar pages [PDF]

You only had to go a couple of hits down to find information. Hardly searching through 1000 of "irrelevant hits". A computer literate person that claims to be such a audio wealth of information should have been able to do this in a couple of minutes.

Bob

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Reply to
Bob Urz

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