New to me JBL L40

View attachment 1233899 View attachment 1233900 View attachment 1233901 View attachment 1233902 I’ve been lusting for a pair of JBL speakers for a while. I found this very nice pair of L40 here in Montréal. They are all there and most of all they really sound great with my Mcintosh... I’m listening to some Led Zeppelin and I have to say I’m really impressed.
I love my ZU Omen but these little beasts really kick it up a step higher.

They bass sounds full and rich, the tweeters are set at 7 and they light up the highs just right - the 12 string guitar sound like it in the room with me...anyway I’m really happy
I’ll lsten for a while then I’ll resyore them.
I would love your help.
Led Zepp ll sounds great on older JBL monitors...as do most rock lp's of the era. The L 40 is a nice speaker...did not use the best of JBL 10" drivers. I worked JBl Pro for 25 years outfitting recording studios. Without a doubt a recap of the crossover won't hurt. If they play well just enjoy them!! Listen to Tektons if you REALLY want to be suprised!!
 
What do you guys think about the colour of the paper diaphragms? I hope they clean well..

Normally, the paper cone color is a light gray. They sometimes fade a bit if left in direct sunlight. Usually a light wiping with a moist cloth is all that is needed to clean dust off, the moisture will dry.

I see that you tinted them black with ink, hopefully the ink dried very well without damaging the cones or adding unwanted weight. The compressed pulp is originally vacuum dried into shape and held by whatever proprietary material / liquid that is part of the pulp slurry. Normally don't recommend ever wetting a JBL paper cone because we don't know what it might do to the structural integrity of the cone. That said, if for some reason the cone collapses or creases on hard excursion or driving, the JBL 127A or H (used in the L40A) woofer is not particularly hard or expensive to find and replace. You can get recone kits also to use but almost cheaper to just replace the whole woofer with an OEM original.

Its not clear from the pics you've posted, do the cones look uniformly black or are they a little blotchy? Same for the tweeter flanges, they look like there's some black blotching around the edges and mounting holes. Flash pics will highlight visual defects. However, normally, the nice 3D grill cover should be in place.

The L40 crossover is pretty simple. Replacing the caps would be simple even if not needed. The schematic is in the thread below...

http://audiokarma.org/forums/index.php?threads/jbl-l26-vs-l40.656574/

Enjoy ! :thumbsup:

Agree. If you want to do anything aside from DeOxiting the tweeter control, replace the two capacitors - one is a non-polar electrolytic and the other is a cardboard wrapped mylar. The NPE is 24uF and the mylar is 6uF. For the NPE, you can use a quality NPE replacement or a large (and usually expensive) film (metallized polyester or polypropylene) replacement. For the mylar, a polypropylene cap is recommended. Since you're in Montreal, consider purchasing from Parts Connexion, I've used their Axon caps with very good results. Leave the resistors and inductors alone.

http://manuals.harman.com/JBL/HOM/Technical Sheet/L40 ts.pdf

So restoration begins but a couple of questions first.
1) would you keep the installation baskets, pic 2?
2)What is best way to remove JBL Lpad
Instruction plate pic 4?
3) is there anything to do to the woofer and tweeter?
4) would you do any thing to the cabinet ie; Bracing?
Thanks

1. YES! The fiberglass basket is part of this particular speaker's design. Its an acoustic impedance loading the woofer and is integral to the acoustic box design. Suggest you retrieve it or rebuild it from 6" wide 1" thick compressed fiberglass strip material (normally used to wrap pipes) and refasten to cabinet. Also, do not add polyester stuffing, the cabinet should be lined with the original fiberglass material.
3. Nothing other than normal foam surround replacement for the woofer. Only investigate the 033 tweeter if it sounds tizzy or spitty in presentation. It is normally a pretty decent and smooth tweeter.
4. no additional bracing is needed. JBL cabinets are quite stout and well built.

IMO, the best thing to do for the speakers is to clean the cabinet veneers thoroughly and try to remove the plant ring stains. Some use a light amount of oxalic acid to lighten the area and then when improved, a light sanding will take it out. Some like using Murphy's wood soap to clean, especially if any smoke residue is noted. Once cleaned, a good mineral spirits wiping will remove any residue. Then a good inspection of the veneer for scratches or gouges which, if needed, can be raised with the moist towel / hot clothes iron method. A light sanding should get you smooth, then stain or oil finish. Others may prefer to use a poly finish but beware this will seal the veneer. Some would just simply clean, sand and use an oil finish, tung oil finish, Howard Restor-A-Finish and then Feed-N-Wax.

JBL veneers respond well to good care and IMO, nothing looks better than a well restored JBL Walnut cabinet.

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Here's a nice variation on the consumer L40, a pair nicely restored with JBL Professional Blue front baffle, note the JBL veneer appearance. Looks exactly what JBL Pro would have produced.

Zonker92, note the nicely designed and built stands.

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Like the pro blue baffle...What JBL did at least with the studio monitors is this....during quality control if the veneer was not quite up to snuff,
the cabinet would be pulled from the line and a carpenter would hand finish the cabinet.
 
Nice elegant stand design! I’m not normally a fan of painting the home-model baffles blue, but those actually do look great.* Makes me think about doing it to the L110s I’m restoring now ...

(*My only quibble: The woofer gaskets are wrong.)
 
Nice elegant stand design! I’m not normally a fan of painting the home-model baffles blue, but those actually do look great.* Makes me think about doing it to the L110s I’m restoring now ...

(*My only quibble: The woofer gaskets are wrong.)

Yeah, the gaskets are sometimes like this from other aftermarket surround suppliers. The correct neoprene gaskets are available on Ebay in sizes from 8" to 18". I suspect the seller bought a ton of them from JBL long ago.

As for painting the L110's blue, then you'd have psuedo 4313's. Evolutionary compact 10" woofer 3 way design.
JBL_L110_1st_rt4_630x431_pixels.gif

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Like the pro blue baffle...What JBL did at least with the studio monitors is this....during quality control if the veneer was not quite up to snuff,
the cabinet would be pulled from the line and a carpenter would hand finish the cabinet.

Joe, what years and areas did you work for while at JBL Pro? Who there did you know? Always welcome former JBL employees also at Lansing Heritage @ www.lansingheritage.org
 
Based out of Las Vegas: started with Lansing in 1982. Northridge factory: Floyd Toole's secret garage. retired 2007
 
Normally, the paper cone color is a light gray. They sometimes fade a bit if left in direct sunlight. Usually a light wiping with a moist cloth is all that is needed to clean dust off, the moisture will dry.
Thank you for you very detailed response Mech986,

I see that you tinted them black with ink, hopefully the ink dried very well without damaging the cones or adding unwanted weight. The compressed pulp is originally vacuum dried into shape and held by whatever proprietary material / liquid that is part of the pulp slurry. Normally don't recommend ever wetting a JBL paper cone because we don't know what it might do to the structural integrity of the cone. That said, if for some reason the cone collapses or creases on hard excursion or driving, the JBL 127A or H (used in the L40A) woofer is not particularly hard or expensive to find and replace. You can get recone kits also to use but almost cheaper to just replace the whole woofer with an OEM original.

The India ink I used was very fast drying, i don’t think it added much or deformed the cones. I used a good quality paint brush and basic just gave it a fast single coat following the round of the cone, the KenRick Sound showed in their video.

Its not clear from the pics you've posted, do the cones look uniformly black or are they a little blotchy? Same for the tweeter flanges, they look like there's some black blotching around the edges and mounting holes. Flash pics will highlight visual defects. However, normally, the nice 3D grill cover should be in place.

The cones dried uniform and the blotchinng on the 033 flange is just some finger marks from the oil finish before I wiped them down.

Agree. If you want to do anything aside from DeOxiting the tweeter control, replace the two capacitors - one is a non-polar electrolytic and the other is a cardboard wrapped mylar. The NPE is 24uF and the mylar is 6uF. For the NPE, you can use a quality NPE replacement or a large (and usually expensive) film (metallized polyester or polypropylene) replacement. For the mylar, a polypropylene cap is recommended. Since you're in Montreal, consider purchasing from Parts Connexion, I've used their Axon caps with very good results. Leave the resistors and inductors alone.

http://manuals.harman.com/JBL/HOM/Technical Sheet/L40 ts.pdf



1. YES! The fiberglass basket is part of this particular speaker's design. Its an acoustic impedance loading the woofer and is integral to the acoustic box design. Suggest you retrieve it or rebuild it from 6" wide 1" thick compressed fiberglass strip material (normally used to wrap pipes) and refasten to cabinet. Also, do not add polyester stuffing, the cabinet should be lined with the original fiberglass material.
3. Nothing other than normal foam surround replacement for the woofer. Only investigate the 033 tweeter if it sounds tizzy or spitty in presentation. It is normally a pretty decent and smooth tweeter.
4. no additional bracing is needed. JBL cabinets are quite stout and well built.

IMO, the best thing to do for the speakers is to clean the cabinet veneers thoroughly and try to remove the plant ring stains. Some use a light amount of oxalic acid to lighten the area and then when improved, a light sanding will take it out. Some like using Murphy's wood soap to clean, especially if any smoke residue is noted. Once cleaned, a good mineral spirits wiping will remove any residue. Then a good inspection of the veneer for scratches or gouges which, if needed, can be raised with the moist towel / hot clothes iron method. A light sanding should get you smooth, then stain or oil finish. Others may prefer to use a poly finish but beware this will seal the veneer. Some would just simply clean, sand and use an oil finish, tung oil finish, Howard Restor-A-Finish and then Feed-N-Wax.

That plant pot ring was a bitch to work on, I tried everything oxalic acid and lots of sanding, it will not go away and I am scared to sand too much and go through the veneer, so I’ll see what I’ll do next...

JBL veneers respond well to good care and IMO, nothing looks better than a well restored JBL Walnut cabinet.

l40.JPG
t25GwJGfhKiVfGeO.large
33374850266_6c5946c041_b.jpg
3%253A4%2Bleft.jpg
 
2704DF24-2BEE-434A-9CD0-E8AAE253C8CE.jpeg 56E41DDF-3DA7-4E07-AB94-F0EF7B263337.jpeg 17CC5C15-3BC7-4D22-8DB7-3F7D9DE76E0E.jpeg Here they are with the speakers stands, these U.S.A stands are about 15lbs each sand filled very impressed with the finish and quality...I have the say the sound with these stand seem to focus the sound stage.
Thank you for all your input!
 
Led Zepp ll sounds great on older JBL monitors...as do most rock lp's of the era. The L 40 is a nice speaker...did not use the best of JBL 10" drivers. I worked JBl Pro for 25 years outfitting recording studios. Without a doubt a recap of the crossover won't hurt. If they play well just enjoy them!! Listen to Tektons if you REALLY want to be suprised!!

Hey joe, I am enjoying them and you know what, they sound really good with a softer style of music too. Records like Adele or Sade are remarkable!
Are you saying surprised good or surprised bad?
 
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Hey joe, I am enjoying them and you want they sound really good with a softer style of music too. Records like Adele or Sade are remarkable!
Are you saying surprised good or surprised bad?
Most of rocks greatest engineers used JBL monitors in the studio in the 70 most 43 and 44 series. If given the chance listen to rematered Hendrix thru 4311's and some big old SS amps (SAE, Soundcratsmen) and you'll hear what Eddie Kramer was really doing
 
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Most of rocks greatest engineers used JBL monitors in the studio in the 70 most 43 and 44 series. If given the chance listen to rematered Hendrix thru 4311's and some big old SS amps (SAE, Soundcratsmen) and you'll hear what Eddie Kramer was really doing
Funny you are saying that, I’m thinking of getting a pair of 4311 here in Montreal, they are the grey finish. Not perfect but all there.
 
At the end got a pair of really nice L100 with reproduction waffle grills, sound great especially with a well recorded record.
The L40 are for sale now :)

They are Sold -01/2019
 
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