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[mark jansen]

Hello,

Hope anyone can help.
One of my old RS880 its JBL2426 died (no resistance at all).
While opening the JBL2426 I noticed the black speaker terminal (JBL2426) is wired to the + marked on the diaphr. Is this correctly wired ? Normally you would assume that red is wired to + on the diaphr.....

Regards,

Mark

[Jens Palm Bacher]

Hello,

Hope anyone can help.
One of my old RS880 its JBL2426 died (no resistance at all).
While opening the JBL2426 I noticed the black speaker terminal (JBL2426) is wired to the + marked on the diaphr. Is this correctly wired ? Normally you would assume that red is wired to + on the diaphr.....

Regards,

Mark

http://www.jblpro.com/BackOffice/ProductAttachments/JBL_TechNoteN1V12C_v5.pdf

[mark jansen]

http://www.jblpro.com/BackOffice/ProductAttachments/JBL_TechNoteN1V12C_v5.pdf

Well many thanks for that link.
Seems like indeed the negative wiring is correct So that problem has been solved.

Another question, while removing the diaphr I noticed that:
-the diaphr. had just a little bit of brown kind of fluid on it (almost neglectable)
-same to the magnet gap (almost neglectable)

As JBL specs do not show any info on ferrofluid cooling, still could this have been remains of ferrofluid ?
Does a new diaphr (in this case Radian 1225-8) need ferrofluid for additional cooling ? Would this make any sense. JBL confirmed me no ferrofluid is needed ! Radian however wrote me some prefer ferrofluid but it is not needed.

[Riley Casey]

Installing Ferrofluid will yield 'undefined' results.  It will most likely increase power handling but it will also change the response.  As you are changing the diaphragm from the original you are already creating a mismatch with any drivers still containing JBL original parts.  As such you would probably do well to follow the diaphragm makers instructions.

Well many thanks for that link.
Seems like indeed the negative wiring is correct So that problem has been solved.

Another question, while removing the diaphr I noticed that:
-the diaphr. had just a little bit of brown kind of fluid on it (almost neglectable)
-same to the magnet gap (almost neglectable)

As JBL specs do not show any info on ferrofluid cooling, still could this have been remains of ferrofluid ?
Does a new diaphr (in this case Radian 1225-8) need ferrofluid for additional cooling ? Would this make any sense. JBL confirmed me no ferrofluid is needed ! Radian however wrote me some prefer ferrofluid but it is not needed.

[mark jansen]

Installing Ferrofluid will yield 'undefined' results.  It will most likely increase power handling but it will also change the response.  As you are changing the diaphragm from the original you are already creating a mismatch with any drivers still containing JBL original parts.  As such you would probably do well to follow the diaphragm makers instructions.

Well I am switching to Radian due to positive experience made by some people I know.
The sound of the 2426 basically I like less than the sound of the VHF100.

If to use Ferrofluid, how to apply and how much per speaker ?

[Rory Buszka]

Well I am switching to Radian due to positive experience made by some people I know.
The sound of the 2426 basically I like less than the sound of the VHF100.

If to use Ferrofluid, how to apply and how much per speaker ?

There are multiple grades of ferrofluid available, with different viscosities that are better suited to LF, MF, and HF drivers. (Community is one of the few companies I can think of that ever made ferrofluid-cooled LF drivers.) To get the same performance, you'd need to use the right grade of ferrofluid for the speaker. While the original JBL driver probably did not use ferrofluid, it is possible that Community disassembled the stock drivers and added ferrofluid to the magnetic gap, and then designed the voicing of the speaker with the driver that had the ferrofluid added.

Look in the gap and see if you can see any of the brown liquid left. If so, you're probably all right to just install the new diaphragm and let that work with the remaining ferrofluid.

[Barry Singleton]

With or without ferrofluid it's already "undifined" as genuine JBL diaphragms don't have a + mark on them, just a red or green mark on one of the terminations.

[ProSoundWeb Community]