JBL 4311's = system complete... for now.

[asilker]

How did you handle the deep scratches? Did you sand the whole things down and then stain?

Mine have a few scratches that make it through the veneer, particularly on the corners. Think I'll try to track down some of the Howard's you mentioned. I'm not trying to go crazy with the cabinet restoration, just clean them up a bit and let them keep some of their used character.

yup I sanded and Minwaxed. But honestly now that I've used restore a finish, I'm not convinced the minwax did a better job. try it first, I bet it works deeper than youre expecting

 

[TheCasual]

Nice work on the 4311B's and welcome to AK!

You will be coming back and acquiring more gear now, guaranteed You can find Howards Restore-a-Finish just about anywhere, Home Depot, Lowes, ACE etc.
Great stuff, you will see a big difference immediately without going crazy on the veneer. You can always sand later if you need to.

Thanks for the welcome, I think I'll stick around . I really just felt compelled to share since it was this thread solely that got me to go for it anyway. Here's to hoping someone else stumbles upon this and does the same.

yup I sanded and Minwaxed. But honestly now that I've used restore a finish, I'm not convinced the minwax did a better job. try it first, I bet it works deeper than youre expecting

Awesome, I'll give that a shot this weekend and update with results.

 

[rollcentre]

Nice work on the foilcals!!! Nice work all around!

 

[mech986]

I tried to save them. So far I've opened the one's seen in the pic and both actually had parts of the wiring broken and unraveled and was being dragged along as you turned the knob. The ones on the other speaker might be better. The problem is that these speakers were owned by a heavy smoker. The knobs moved as if they had honey inside. The once white woofer is now the color of a used cigarette filter.

If the resistance elements are shot, replace the L-pad, there is no saving it. If there was a smoker, the electrical components should be replaced pretty much too. I would replace them in pairs with the Parts Express units mentioned elsewhere in the thread, or get a good used pair from any JBL which uses the same part number listed on the tech sheet - a ton of JBLs used this same combo of mid and tweeter models, so same L-pads.

There are a number of threads dealing with how t possibly clean or re color the woofers. If the cone and surround are otherwise intact, you're better off than most who have woofers which have suffered some type of tear or structural damage.

Thanks for the welcome, I think I'll stick around . I really just felt compelled to share since it was this thread solely that got me to go for it anyway. Here's to hoping someone else stumbles upon this and does the same.
Awesome, I'll give that a shot this weekend and update with results.

For mild to deep scratches, if it has not fully penetrated deep under the veneer, you can use a steam raising method. Get an electric iron and a moist cloth, not dripping wet. Locate the area with scratches, clean and wipe down so no dirt. Heat the iron to a cotton temp, lay the moist cloth over the scratch or gouge, then heat using the tip or upper 1/4 to 1/3 of the iron. Apply for ten seconds or so, usually a little steam maya rise. Don't over apply as it's possible to burn the veneer if too hot or too long. The scratched fibers will absorb the moisture and swell, filling in the scratch. Re moisten the cloth and reapply as needed till the scratch is filled or slightly raised for sanding. Then move on to the next scratch or area.

Resist the urge to apply heat to a large area all at once, it's harder to control the entire iron heating surface and the body of the iron bottom is much hotter.

Once done, you can lightly sand or use Restor-a-Finish with steel wool or similar to apply and lightly sand. JBL veneers respond very well to TLC if not extensively damaged.

We need before and afters on your work. As always

 

[TheCasual]

We need before and afters on your work. As always

As commanded:

Basic supplies, feed 'n wax not pictured.

Prepping the foil cals for replacement. The top edges were a bit shiny, probably as a result of their original extraction from the speaker. I hit the top edge of it with a sharpie, it actually looked nice I thought. I used the paint thinner to get all of the old adhesive off the foil cals. 3M spray adhesive applied liberally before putting them back on. Paint thinner on a rag to wipe up the excess after pressing the foilcals on nice. Pic below shows foil cal with and without the sharpie treatment.

In Re the deep scratches on the bottoms: I don't actually own an iron but my girlfriend does have a steamer.

The following pics show the same cabinet face in three stages of the process-> first raw, then after a steaming of the deep scratches, and then after a coat of Howard's Walnut Restor-A-Finish.

One more before / after:

And now let's just jump ahead to the finished product after a coat of Feed-N-Wax:

Honestly, I'm a bit astonished how easy this was and how great they look. The original scratches and signs of use are still there but they aren't nearly as in your face. Once again the people here have not steered me wrong.

Cheers

 

[asilker]

And now let's just jump ahead to the finished product after a coat of Feed-N-Wax:

Honestly, I'm a bit astonished how easy this was and how great they look. The original scratches and signs of use are still there but they aren't nearly as in your face. Once again the people here have not steered me wrong.

Cheers

Those look lovely. I wasn't crazy about the way mine sounded (personal preference) but dangit if I wouldn't jump on another pair just for how dang good they look!!

 

[mech986]

Very nice work, well done. As for the sound, if the original or recapped crossovers don't work for you, there's the Murphy modification or the more expensive and extensive mod from Troels Gravesen which smooth them a lot. Nothing wrong with trying out a mod to the crossovers.

 

[the_nines]

Great work indeed.

 

[asilker]

Very nice work, well done. As for the sound, if the original or recapped crossovers don't work for you, there's the Murphy modification or the more expensive and extensive mod from Troels Gravesen which smooth them a lot. Nothing wrong with trying out a mod to the crossovers.

If I had kept mine, I would have done the troel gravesen crossover. To me this seems like an obvious improvement

 

[Dror Becker]

Hi,

I recently got a pair of 4311.


The Presence and Brilliance controls don't seem to do anything though... and the sound is kinda bass heavy.
Do I need to follow the OP and replace the pots and caps?

Thanks!

 

[mech986]

Hi Dror, Welcome to AK! Should consider first taking out each driver and checking that they are correctly connected to the crossover wiring. Then test driver with a meter for a DC resistance reading (document it for each driver), and then play a low level signal of appropriate frequency into each driver to assess operation. If the drivers have problems, this will reveal it. If the drivers seem to be working fine and each pair of woofers, mids, and tweeter checks out ok, then you should look into cleaning the L-Pads first and see if the sound comes back and is more balanced. If not, then check the crossovers for bad solder joints, cracked wiring, or failure of the capacitors or inductors.

If these were used in a studio working environment (studio gray), the systems could have certainly been subject to overdriving or damage, or just worn out with use.

 

[Dror Becker]

Hi, Thanks for your help!

I checked the ohm of each driver and got this:
Left Speaker -
2212: 5 ohm
LE5-2: 5.4
LE25: 4.2

Right Speaker -
2212: 5 ohm
LE5-2: 5.8
LE25: 4.4

Is this normal? How do I test each driver with a signal?

Thanks again!

 

[Dror Becker]

You need a signal generator like this simple one but the values indicate the voice coils in the drivers are intact. I'd pull out the crossover and check the L-Pads and other components like you'd been advised earlier. It's very common for the L-Pads to develop dead spots. They need to be, at the very least, thoroughly cleaned with DeOxit or other contact cleaner. You can use a hair dryer to slowly heat up the foilcal and peel it off with a thin putty knife to clear access to the screws.

Thanks!
I'll take the crossover out. The controls have no effect when I turn them, can it still be just the L-Pads or is it more likely faulty components?

 

[Dror Becker]

I just took the crossovers out and they look different than the others I've seen:
R:
L:

 

[mech986]

The below crossover indicates one of the L-pads isn't even connected!! On closer examination, it appears all 4 of the controls are not L-pads at all, at least no JBL OEM types - they look much more like common low power, low level control pots. I can't quite make out the writing on the back, but they don't look JBL to me. As tnsilver notes, the crossovers have been messed with so all bets are off IMO.

Here's what the factory OEM parts should look like:

See the first post in this thread for details and parts lists at least using the same circuit with parts to suit sound preference tastes. Otherwise, you could consider some crossover circuit changes, particularly the Murphy crossover design, or the Troels Gavesens mod. http://www.troelsgravesen.dk/JBL_L100.htm


Another thread with a rebuild is:
http://www.audioheritage.org/vbulletin/showthread.php?35339-4311-resurrection

 

[Dror Becker]

Just wanted to follow up.
I repaired the crossover with the "improved original" parts and the speakers sound really really great!!
I'd like to thank you both for your help!

 

[Giovanni68]

Hello,

I have been following this thread since quite a while and after seeing successful x-over updates and reading about results I am very tempted to give it an attempt.

I bought my 4311B when I was a teen (and am not any longer since quite a while), back then the source was a Technics direct drive SL-D303 (which is still somewhere) and a Sansui AU-D7 which also is still on a shelf, I recently updated my music setup with an Audio Research SP9 preamp and a Michell Gyrodec turntable (which I have to restore with new belt and new head shell wires), amp wise using an old Carver but soon going to get a tubes one, an Aaron.

By the way, I many years ago did attempt to remove the woofer to see what's hidden inside there but it didn't come out, well, gave up the idea of exploring the inner of the box but now I'd like to perform some update of the crossover since it seems it could bring the 4311b back to life, my concern is first and foremost how to remove the front plate off the cabinet (I own a heater which I use to remove paint off of wood, it basically is a very hot hairdryer, could I use that at low power without to risk to make some damage?) and how to take the speakers off, once I can get past this I should get the new components and since I live in Italy I would need the parts list to try and find out.

Any good soul out there who wants me to help revitalize my 4311b?

Thank you

Giovanni

 

[tnsilver]

Do not use down force on the screw driver when you take out the 4 woofer bolts or you'll push the wood nut down and find your self in an awkward trap where the nut is inaccessible. Be very gentle with the screw driver. Once unscrewed, the woofer is caulked to the box. You will need to use a flat screw driver to release it with some force. You could use a thin block of wood for leverage. There's slight chance the old caulk would pull up some paint and fiber off the box. You will need to smooth this out and sand the mount hole before applying new caulk or reusing the existing caulk. For the foil cal, I'd use a hair dryer, not a heat gun (may damage the plastic L-Pads caps) and insert either a very thin putty knife or a leaf gauge under the cal. Easy does it. Take your time and do not be tempted to lift the foil cal before it's completely detached from the box.

 

[ictwoody]

Yo dudes. Thanks to this thread I just redid the crossovers for the JBL 4312’s I’m resto-modding. I thought some of you would appreciate seeing my completed crossovers using the parts listed in this thread for the improved original configuration.

I went ahead and replaced my L-Pad’s with the ones from PE. Figured I might as well play it safe.

Here’s the results. As well as some comparos with the original.

- Woody

 

[tnsilver]

Thanks to this thread I just redid the crossovers for the JBL 4312’s

and a beautiful job at it too. Very well looking and neatly executed XO's. Are the caps fixed to the masonite? You might wanna add a touch of hot glue / silicon for damping if they aren't. very nice!