Distortion on 435Be

[cooky1257]

Hello all,
Do any of our resident experts have any opinions on what could give rise to distortion in the 435Be section of some K2 S9800's?
Crossovers have been swapped and the fault appears to be the speaker driver.The owner assures me they are well loved and haven't been overdriven.
I've heard surround creep mentioned and also cap foam coming unstuck.
The owner is in the UK and approved service centres are very very very thin on the ground.

Any suggestions/advice would be most welcome.

Thanks

Cooky

[Andyoz]

Hi Cooky,

I have no idea what the problem is but how do you find the 9800 sound. I have never heard them but hope to own a pair one day???

[cooky1257]

Hi Andy,
I'm not on the receiving end of the S9800's so can't comment-I'm just trying to help someone out.

Cooky

[Lee in Montreal]

I suppose that if the driver was owered directly off an amp, with a cap to filter out lower frequency, it would easily help find the problem.

[Andyoz]

Hi Andy,
I'm not on the receiving end of the S9800's so can't comment-I'm just trying to help someone out.

Cooky

I was hoping you might have heard them first hand?

[Robh3606]

Try doing a slow low power sine sweep. Might help you pin point it or at least give you a range of frequencies where the problem is. Could be as simple as the cover screws being loose or a wire.

Rob

[cooky1257]

I've suggested he check the bolts too-without over-tightening them:eek:
I may just get him to remove the driver and send it to me so I can give it a clean/recharge the ferrofluid/sweep etc.

Thanks chaps.

[cooky1257]

The chap with the distorting 435 has sent me these pics of the unit in question.

No ferrofluid but lots of flakey trim in the gap..

http://farm8.staticflickr.com/7019/6624257461_778381ce75_z.jpg

http://farm8.staticflickr.com/7028/6624256669_bc7186a0fc_z.jpg

[JeffW]

What is that? Looks like plating coming loose.

[Robh3606]

Crap that sure looks like the plating. In the gap as well yikes! Those are in 9800's can't you get a new driver through the waranty?? Couldn't hurt to ask that is a manufacturing defect. You could also get a 2431 core and just change out the diaphram and cover.

Rob:blink:

[cooky1257]

Shocking isn't it?
The other thought that came to mind was they'd been opened and the crap from the trim had headed straight for the gap...

The 2431 cores idea is a good one, I'm told the speakers are out of warranty
and the dealer is attempting to contact the JBL rep over the holidays.

[Mr. Widget]

The 2431 cores idea is a good one, I'm told the speakers are out of warranty
and the dealer is attempting to contact the JBL rep over the holidays.If the drivers are from a K2-S9800 and they were purchased through a legitimate dealer, I would think they'd be covered even if past the 5 year limit.


Widget

[Titanium Dome]

That picture is frightening and somewhat disconcerting. The 435Be is in other product as well.

If the driver hasn't been tampered with in some way, what might account for this degradation? In addition to manufacturing defects, are there usage or environmental factors that might cause this?

Though I'm not right on the Pacific Ocean, it's not far away. I wonder sometimes about the effects or marine air on some of my equipment. Is the owner living near the sea?

[Mr. Widget]

Is the owner living near the sea?Ever look at a map of Britain? ;)

I don't see corrosion, it looks like an original manufacturing defect to me.


Widget

[Robh3606]

Though I'm not right on the Pacific Ocean, it's not far away. I wonder sometimes about the effects or marine air on some of my equipment. Is the owner living near the sea? It has nothing to do with that. It's a plating failure on the NEO magnet. That's one of the reasons it's all in the gap as well. I am suprised the top plate has not shifted.

It could be from a bad plating batch on the NEO magnets so it could be in 2431 as well. Could be an isolated incident as an example the magnet was not prepared properly. If you took masking tape and put it on the area that is peeling it would take most of the "loose" stuff right off.

Yeah know what stikes me is odd is the finish on the magnet. The ones I have are black yet this one seems to be silver almost looks like nickel plating?? I have to check my drivers when I get home. Here's picture of the one I had the shifted top-plate on. You can see the black magnet sandwitched.

Rob

[JeffW]

Unless they started plating the magnets for some reason. I know the environmental guys don't like exposed neo magnet material, plating magnets in small, high performance electric motors was a point of contention a while back.

[cooky1257]

Just checked my pair of 2435's and they are black finish-don't look plated.

The dealer is no longer selling JBL, they were shop demonstrators and are 1 year out of warranty.

[Lee in Montreal]

The dealer is no longer selling JBL, they were shop demonstrators and are 1 year out of warranty.

The dealer will usually take care of the "official" warranty. Then, there's a non-explicit warranty from the manufacturer. Even though they warranty a product for, say, a year, that product should have a longer troublefree life. If you pay $3k for speakers, you expect them to last longer than the 1 year warranty. At that point it becomes a case by case negociation. If JBL is not responsive, small claim court is cheap and usually brings good results.

Seeing that plating was replaced by black aint is perhaps a sign that JBL knew something was wrong and a great leverage to negociate replacements.

[Mr. Widget]

The dealer is no longer selling JBL, they were shop demonstrators and are 1 year out of warranty.Contact the UK distributor and find out what can be done. 1 year or 5 years out of warranty, that is unacceptable and JBL will most likely resolve the issue... if you get to the right people.


Widget

[cooky1257]

Thanks all,
I'm passing all this info on.
Cooky

[grumpy]

When comparing magnet colors and plating, keep in mind that the 2435 and 435Be
are separate products, albeit with similar origins...
nearly all of the 435Be photos I've seen show plated magnets (I found one exception,
with no guarantee that 435Be back caps weren't installed on 243x drivers).

[JeffW]

At least 2 of my 435AL drivers have black (or at least non-plated) magnets. Not sure of the others, and not sure how close the 435AL and 435Be are related.

[Robh3606]

Not sure of the others, and not sure how close the 435AL and 435Be are related.

They are identical functionally except for the diaphragm material as are the 2431 and 2435. Curious about Grumpy's point. You can just change out all 4 diaphrams and covers they all use the same core structure.

Rob:)

[Robh3606]

nearly all of the 435Be photos I've seen show plated magnets

Could you share them. I have only seen the black and the drivers we got from JBL for Project May were black as well. One of them is in the photo Bo took when we first got them. Gregs drivers have the black magnets as well. The plot thickens!

Rob:)

[grumpy]

Sorry it took so long... some were 'user' supplied, some from JBL literature:

[grumpy]

Then there's this one (so it's likely something changed, or US vs. elsewhere supplier or version):

54324


There there's the hand model ;) :

http://www.audioheritage.org/vbulletin/showthread.php?1590-435Be&p=13935&viewfull=1#post13935

[Robh3606]

Thanks Grumpy:applaud:

So maybe the earlier versions were plated?? Or maybe they had different sources for the magnets and they were finnished differently??

Rob:)

[grumpy]

Dunno... pure speculation at this point re why some were "silvered."
Might have been a finish thing... on some speakers models, they
poke out the back of the horn and are visible, some they don't.
:dont-know:

Regardless, it does -seem- like a replacement from JBL would be appropriate
in this particular case, where the finish not only came off, but -appears- to have
migrated into the gap.

[JeffW]

Makes me wonder if there was a "Euro" version that required the bare Neo material to be plated over. Seems unlikely, but in the context of the motor magnets I mentioned earlier, it's not out of the realm of possibilities.

[Predrag Dukic]

Makes me wonder if there was a "Euro" version that required the bare Neo material to be plated over. Seems unlikely, but in the context of the motor magnets I mentioned earlier, it's not out of the realm of possibilities.

You will never see "Bare" Neo material in any of the industrial uses. NdFeB material is very susceptive to corrosion, so it is always plated or covered in epoxy.
Bare Neo material looks like gray pressed dust. Protection from corrosion is still unsolved problem,because everything really easy peels off the magnet.
Magnet material itself is brittle and low strength, protective layer bonding can't be any stronger than the underlying material...