Ross Herbert wrote:
On Fri, 19 Jan 2007 18:36:48 -0600, BOB Urz "sound"@(remove)
inetnebr.com wrote:
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
http://manuals.harman.com/INF/CAR/Owner's%20Manual/KAPPA%20PERFECT%206-1%20om.pdf
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 he
http://www.apicsllc.com/apics/Misc/filter2.html
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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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.
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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