• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

JBL 4311B refurb questions

Danbo69

Danbo69

Active Member
I have recently acquired a pair of 4311Bs from a local thrift shop. Overall they are in pretty decent shape, but I am planning on refurbishing them to make them look new again. I'm pretty comfortable with redoing the cabinets as I have pretty decent woodworking experience and done several cabinets that have turned out very nice. I do however have a couple of other questions that perhaps some of you who are more familiar with these can answer:

There is a goop that has leaked down from the woofer and has run down the face of the speaker. It seems like a sealant from the woofer surrounds and in practically every picture of one of these I have seen it, so I know it's a common issue. First question, what works to clean that off without removing the paint on the speakers? Second, do I need to put some sort of sealant on the surrounds to keep them from drying out?

Speaking of the woofers, it seems most of the pictures show the black leads on the white cones canted to the left, but on mine they are canted to the right. It seems like mine have been that way for a very long time as the goop from the woofer surrounds has run down as they sit. I know it would simply be a matter of turning the woofers 90 degrees, but am curious if there is a "correct" way that these came from the factory, or if mine have been manipulated at some point?

Finally, how important/difficult is it to replace the capacitors on the crossovers? These have large, cardboard capacitors, and I haven't pulled mine out to look at them yet, but is this a must do, or a should do?

Thanks
 
Last edited:
Register to hide this ad
Can you post some photos of this goop? And what other issues you may have with the speakers.

I changed the sandbox caps in my old L100. I used ERSE ones.
 
I believe it is some type of adhesive or a coating on the surrounds. It is very sticky, and when I heat it up it becomes more viscous. I assume it has melted and run down the face of the speaker due to being exposed to heat over time. I've seen this on pictures of other 4311Bs online, so I know it's not unique to this pair.

On another note, this speaker has the black leads by the cone canted to the right, and it has clearly been that way for a long time due to the leaking goop. It seems most every picture I see has the leads on the left-hand side. I know it's a minor aesthetic thing, but does anyone know if these all came from the factory facing to the left?

As far as any other issues, the connection plate in the back of one of the speakers had come loose, but some wood glue and staples put it back in place, and the other speaker had a loose connector, but a couple of twists with a screwdriver set it right. There is a ding on the front edge of one of the cabinets that put a dent in the plywood, and there is about an inch-long chunk of veneer missing. I've ordered some walnut veneer edging and will work to repair that.


PXL_20230924_141846448.jpg
 

Attachments

  • PXL_20230924_141852776.jpg
    PXL_20230924_141852776.jpg
    123 KB · Views: 5
Danbo69 said:
I believe it is some type of adhesive or a coating on the surrounds. It is very sticky, and when I heat it up it becomes more viscous. I assume it has melted and run down the face of the speaker due to being exposed to heat over time. I've seen this on pictures of other 4311Bs online, so I know it's not unique to this pair.

On another note, this speaker has the black leads by the cone canted to the right, and it has clearly been that way for a long time due to the leaking goop. It seems most every picture I see has the leads on the left-hand side. I know it's a minor aesthetic thing, but does anyone know if these all came from the factory facing to the left?

As far as any other issues, the connection plate in the back of one of the speakers had come loose, but some wood glue and staples put it back in place, and the other speaker had a loose connector, but a couple of twists with a screwdriver set it right. There is a ding on the front edge of one of the cabinets that put a dent in the plywood, and there is about an inch-long chunk of veneer missing. I've ordered some walnut veneer edging and will work to repair that.


View attachment 2993277
Click to expand...
Someone may have added too much aftermarket doping compound to the surround to soften it. They used to sell this stuff in guitar amp shops. Really, no damage, just very messy.

Maybe, remove the woofer. Clean the surround doping off the frame and cabinet. Then, place the woofer back into the speaker at another angle.

https://audiokarma.org/forums/index...ui-speaker-surrounds-leaking-adhesive.863983/
 
I have the cabinets stripped down, and now seems like the best time to tackle my first capacitor replacement even since I won't be able to easily access the screws that hold the crossovers in place once I put the badges back in place. There are two capacitors, an 8.0 uf and a 3.0 uf on each. I know nothing about capacitors, so need some help here. Would these be good replacements: https://www.ebay.com/itm/1219099006...lRXh0G9U/UWE5zw+SMPy8VR1hts=|tkp:BFBMjNmUmuBi

Thanks!
 
Danbo69 said:
I have the cabinets stripped down, and now seems like the best time to tackle my first capacitor replacement even since I won't be able to easily access the screws that hold the crossovers in place once I put the badges back in place. There are two capacitors, an 8.0 uf and a 3.0 uf on each. I know nothing about capacitors, so need some help here. Would these be good replacements: https://www.ebay.com/itm/121909900683?hash=item1c6265758b:g:FyMAAOSwBJxdSWgp&amdata=enc:AQAIAAAA0MGYfdPN+1FwLbclS7P6bdbe7wKxuK3+eW5p+QB8fw94fQSydBtSCLf1G7PMpx+q9/5uvJzvtwlqs4BloFmKazQrAKRSeAJ8MU650yJplo2flO+u6itG8p/WbUiHyDduIhisffZGWIILS8H8tYPN7dbggWWBa2ej29xrIPP6C9cLgmHyWDjyeu9joXAuwnO5GJHsUEi3Tp6GDSSPtQuiI2dloO9q7Ss3ClwYDhH6Pde2oUobMZ87EbnsXR8+lRXh0G9U/UWE5zw+SMPy8VR1hts=|tkp:BFBMjNmUmuBi

Thanks!
Click to expand...
Those look like Solen PPE caps. They are good quality caps.
 
Those woofers have folded edge surrounds instead of the later foam surrounds that deteriorate crack and crumble.
The "goop" was a treatment meant to keep the folds flexible, and not a problem if you rotate the woofers periodically
so the goop stays on the woofer itself and doesn't run down the baffle and look messy on the speaker face.

generic image of a typical pair of 4311B
JBL4311B.png
 
hjames said:
Those woofers have folded edge surrounds instead of the later foam surrounds that deteriorate crack and crumble.
The "goop" was a treatment meant to keep the folds flexible, and not a problem if you rotate the woofers periodically
so the goop stays on the woofer itself and doesn't run down the baffle and look messy on the speaker face.

generic image of a typical pair of 4311B
View attachment 3002844
Click to expand...
Us guitar ppl call it speaker doping. The viscosity and amount apply changes the tonal and response qualities of the speaker.

Many guitar amp speaker companies can custom dope the surrounds, to meet personal specs.
 
Last edited:
Today I sadly discovered that one of the mids and one of the tweeters are dead. I know I can watch eBay and Reverb to see if replacements pop up, but does anyone know of a place that will rebuild these? Tweeter is an LE25-2 and mid is a LE5-10.
 
You must log in or register to reply here.
Back
Top Bottom