If an 8 ohm driver reads a little high in DC resistance

[z-adamson]

Looking at a driver that is listed as 8 ohms and typically reads between about 7 ohms. However, this particular driver I am looking at buying reads 9.9 ohms.

Driver = JBL LE111A

Does this look like a risky purchase? Why would most LE111A driver have a DC resistance of 7 and this particular one 9.9 ohms?

 

[bowtie427ss]

DC resistance should be 5.7 ohms. Something isn't right.

http://www.jblproservice.com/pdf/Thiele Small Parameters/Theile Parameters.pdf

 

[z-adamson]

Interesting, what could cause it to read a few ohms higher in DC resistance?

 

[bowtie427ss]

There are a number of possibilities from loose terminals, to failing tinsel leads, fractured solder joints, recone with non-factory parts, or even a partially burned thru coil or lead wire.

How does it sound/play?

Does the DCR settle to a different value if you move the cone to a position other than it's center/home position?

 

[z-adamson]

Havent heard it or seen it in person yet.

I know it has been refoamed, cone parts are OEM and it plays music. Thats about all I know additional to the high DC resistance.

 

[bowtie427ss]

Here's an interesting JBL document, note the polarity convention as it will help verify an original cone assembly.

 

[z-adamson]

Cool, do you have any more of those?

LE10A, LE14A?

 

[goodolpg]

Introducing an imperfect component into a perfect system seems risky.

 

[z-adamson]

Introducing an imperfect component into a perfect system seems risky.

Understood.

I wasn't sure what kind of problem would cause the slight rise in resistance.

And the system is not what I would consider perfect.

 

[bowtie427ss]

Cool, do you have any more of those?

LE10A, LE14A?

Sadly, no. Just something i stumbled across on the interwebs.

No FR plot, but the impedance curve was still attached: