PDA

View Full Version : L46 cone repair



Stephen Sykes
08-18-2005, 11:11 AM
Hello,
I am new to this list and admittedly a novice at speaker repair/maintenance. My wife and I were fortunate to recently become owners of a pair of L46's. Unfortunately, one of the woofers appears to have been damaged and is producing an undesireable hiss/crackle when bass hits.

Can anyone offer advice on how technical a procedure it is to replace these woofer cones? I have gathered that I need the 117H for replacement. I'm just trying to assess whether this is something I can do or does it need professional attention?

Thanks for your time.
Stephen

Alan Fletcher
08-18-2005, 01:52 PM
Hi, Stephen, and welcome to the forum.

More descriptive info on the driver's malfunction would be very useful. It may not be necessary to recone the driver. A general repair may be possible.

That said, unless you are knowlegeable and/or experienced with a loudspeaker's general functionality-- how they work, why they sometimes don't-- failure modes, etc. , it would be inadvisable to attempt a do-it-yourself recone.
Not only (as I have learned recently) is it nearly impossible to obtain recone kits as an end user, but it also requires proper tools and test equipment to make sure the driver functions properly after the recone.

What sounds is the driver making? Is it a rattling sound? Does it make the noise at all volume levels, or just when you crank it up? Have you tried tapping on the driver with the speaker disconnected from your amplifier and if so, does it make a pinging or rattling sound?

All of this would help us (and there are many here more knowledgeable than myself) to help you solve your dilemma.

Also, please enable location display in your profile settings. It will allow us to see where you are. Perhaps there is someone local to you who could visit and check out the problem. I used to know a Linda Sykes, although I doubt there is any relation.

-Alan

Stephen Sykes
08-18-2005, 02:21 PM
Hi Alan,

Thanks for your response! I will activate my personal settings today, thanks for the tip. I live in Portland Oregon. Incidentally, my mother is Linda Sykes! I wonder if it's the same person? My grandmother lives in Norwichtown CT...

As for the cone performance...the apparent defect is audible at most volumes with high base. The crackling/scratching sound does not occur if the bass is turned down to all the way or close to that.

Any more thoughts on how to diagnose the issue are welcome. I'll try the touching/lightly poking of the cone while it's disconnected to see what happens.

I agree though, these are nice speakers and someone with more familiarity should be working on them. If anyone out there knows of a knowledgeable person or shop in the Portland area I would appreciate hearing about it.
Stephen

Alan Fletcher
08-18-2005, 02:34 PM
Stephen,

I'll send you a private message shortly to take the Connecticut/Sykes thing further, I'll tell you more about what I know/remember(this was back in high school).

Meanwhile, I've done some research on the L46 and it seems to be one of the numerous deviations from the professional-based consumer models I've come to know and love (post Harmon acquisition)... it may be better just replace the driver-- depending on the problem. Where did you get the L46's from? Were they abused, or in a situation where they could have been abused (child or teenager)?

-A

Stephen Sykes
08-18-2005, 04:21 PM
I got them from a guy selling them locally, Portland. He was the original owner and a very sophisticated listener. He had expensive power sources for them so I think they generally got clean power. They are about 14 years old so perhaps this is about the time that they need to be replaced. He used them as monitors for a studio he had for awhile so generally I think they've been well kept.

I'm a little bummed though as my wife and I debated for awhile whether or not to buy them because we already had some decent Bose speakers. These JBL's have such a warm and clean sound though we bit the bullet...
I think I'll contact the best shop in town that I know of, Fred's Heart of Music, and see what they say.
Thanks for your time.

Zilch
08-18-2005, 05:23 PM
http://www.jblproservice.com/service/oregon.html

jay
08-18-2005, 05:30 PM
Stephen, L46's are now 20-25 years old and the woofers' surround edges are no doubt decayed. The way you describe yours is exactly what mine sounded like when I got them a month ago.

Upon casual inspection, mine didn't seem to have bad edges, but a slight bit of pressure and they cracked and separated away from the cones, and worse, revealed that they had been bad for some time.

The 117h 8" woofer comes with a smooth stylish shiny black surround originally, but can be easily replaced with ordinary foam surrounds with good results. I did mine in under an hour, and the bass and overall balance were markedly improved.
Good luck, I hope that's all yours need!

transducergeek
08-18-2005, 07:19 PM
Hello,
I am new to this list and admittedly a novice at speaker repair/maintenance. My wife and I were fortunate to recently become owners of a pair of L46's. Unfortunately, one of the woofers appears to have been damaged and is producing an undesireable hiss/crackle when bass hits.

Can anyone offer advice on how technical a procedure it is to replace these woofer cones? I have gathered that I need the 117H for replacement. I'm just trying to assess whether this is something I can do or does it need professional attention?

Thanks for your time.
Stephen

I will guess with a high probability that your surrounds are shot. I will supply a set of 8" new foam edges with a bottle of adhesive and application brush and instructions for $10+ $4 postal parcel shipping, a total of $14/pair. That should totally fix them/you up... write or call me with any questions... Rolf Erickson.

(310) 372-9113 Phone.

Lightbearer
10-29-2005, 12:12 PM
I allso have a pair of those and earlyer I was very happy with them.. But now both of the woofers donīt seem to be working. There is no hiss or anything just total silence. Do you have any ideas what might be the problem(they seem to be in good condition, not torned or anything). If I have to replace the woofers do you guys know where one can get a pair of them or how to have them fixed...I actually donīt want to throw them away as they are excellent mixer monitors,neutral and precise..

JBLTEC
11-02-2005, 12:01 PM
First post:D .I recently had the same problem with a set of 125A woofers and found that the VC former had blistered on the ID and caused it to rub the pole piece. It was a painstaking process to fix but I was able to produce satisfactory results. I can elaborate if anyone is interested.

Jason