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View Full Version : L40 set. Mods/upgrades/info/resources?



stupidhead
05-09-2015, 04:15 AM
Hello folks. I have recently acquired a set of L40s. For all intents and purposes they are driver-less at this time, and missing grilles entirely. I have enjoyed working on L110s in the past and am considering these for a project. I like the size, and very much like the look of the original grilles. I suspect I will be into these for more than they are worth in the end, but am OK with that. I foresee giving them to one of our daughters for bookshelf speakers.
Somewhere on this site, I have seen tech specs for other JBLs on this site, but I have tried to find a tech sheet for these with no luck. I have explored the library with no luck. Probably right in front of me but if someone could help me find this I would appreciate it. Schematic for xover would be nice to have as well!
I am curious if I should seek out OEM drivers or are there replacements that would be upgrades. The grilles are also going to need to be sourced, and don't know where to begin for that quest. Once I get these on the bench I will take some pics. Cabs aren't terrible, and the insulation baskets are still intact. The cabs will need some treatment for that musty thing and I look forward to this challenge.
Any insights will be much appreciated.

Geoff

Odd
05-09-2015, 05:17 AM
L40
L40a

Woofer
05-11-2015, 08:55 PM
I've got a pair that I've had since the 70's.
Killer bass. Always liked their 'thump' for fun listening.
I thought their sound was OK at the time, but once I got a pair of L36, [3-way versions of the L40], I really noticed what a difference the added mid unit made, but the L40 are still pretty good for what they are.

They normally use a 127A 10" woofer, but you can also use the 125A 10" Only difference is that one has an inverted dust-cap.
The 033 tweeters can be replaced with just about anything. Original tweeters are still sought after by restorers so still fetch a good price.
Either of the above can be sourced easy enough on the 'bay.
The grilles are easy enough to make up. Just need to build a simple frame and cover with acoustically transparent cloth.

Have fun.....

Wagner
05-12-2015, 04:04 PM
Hello folks. I have recently acquired a set of L40s. For all intents and purposes they are driver-less at this time, and missing grilles entirely. I have enjoyed working on L110s in the past and am considering these for a project. I like the size, and very much like the look of the original grilles. I suspect I will be into these for more than they are worth in the end, but am OK with that. I foresee giving them to one of our daughters for bookshelf speakers.
Somewhere on this site, I have seen tech specs for other JBLs on this site, but I have tried to find a tech sheet for these with no luck. I have explored the library with no luck. Probably right in front of me but if someone could help me find this I would appreciate it. Schematic for xover would be nice to have as well!
I am curious if I should seek out OEM drivers or are there replacements that would be upgrades. The grilles are also going to need to be sourced, and don't know where to begin for that quest. Once I get these on the bench I will take some pics. Cabs aren't terrible, and the insulation baskets are still intact. The cabs will need some treatment for that musty thing and I look forward to this challenge.
Any insights will be much appreciated.

Geoff
I like that series; the smaller L20 being the (overly used catch phrase) "over achiever" that "punches above it's weight" of the bunch
Nice as they are, you'd be better off seeking out a complete (if your heart is set on the L40) pair rather than trying to source all of the missing components; because you are correct and then some; it's going to cost you a lot more to do it that way than to just find a complete pair
(unless you are incredibly lucky as in VERY lucky)
Used grilles for this series are also commonly plagued with at least one broken attaching peg as well

I'd suggest just looking for another pair

I'm also not certain what "for all intents and purposes" means exactly; do you have any of the drivers or not?

The only way to resurrect them, "back" into a pair of L40s would be to use the original drivers as designed, although I am sure that with enough careful research there are drivers (other model numbers) that would get you close enough to the systems's original design parameters, possibly even offer some sort of improvement................but that would be another project entirely (JBLs are designed as a "system")

Edit: I'm sorry, when I mentioned the L20 I was thinking of the "T" series, as in "L20T" I think my suggestions would still apply however, maybe even a bit more difficult as yours are from an even older model series (I'm guessing here) Which version of the L40 do you have? The 2-way or the 3-way?

stupidhead
05-14-2015, 03:17 AM
I like that series; the smaller L20 being the (overly used catch phrase) "over achiever" that "punches above it's weight" of the bunch
Nice as they are, you'd be better off seeking out a complete (if your heart is set on the L40) pair rather than trying to source all of the missing components; because you are correct and then some; it's going to cost you a lot more to do it that way than to just find a complete pair
(unless you are incredibly lucky as in VERY lucky)
Used grilles for this series are also commonly plagued with at least one broken attaching peg as well

I'd suggest just looking for another pair

I'm also not certain what "for all intents and purposes" means exactly; do you have any of the drivers or not?

The only way to resurrect them, "back" into a pair of L40s would be to use the original drivers as designed, although I am sure that with enough careful research there are drivers (other model numbers) that would get you close enough to the systems's original design parameters, possibly even offer some sort of improvement................but that would be another project entirely (JBLs are designed as a "system")

Edit: I'm sorry, when I mentioned the L20 I was thinking of the "T" series, as in "L20T" I think my suggestions would still apply however, maybe even a bit more difficult as yours are from an even older model series (I'm guessing here) Which version of the L40 do you have? The 2-way or the 3-way?

Thanx for the responses so far folks. The back story goes something like this.
I found a set of L110s a couple years back and restored them back into fully functional and great sounding speakers. My listening taste is more lined up with the AR sound so I have recently sold them. On another forum a random user was contemplating resurrecting a set of L110s that had been damaged as a result of a break up. I jumped in the thread and encouraged the rebuild. He was lacking an 033 tweeter and was assembling all needed items for the restore. As things often fall together, as I was making final plans for the sale of my L110s, another forum member posted that he had a set of L40 cabs which had other than JBL woofers that he was going to use and one of the remaining 033s was dead and one good. Cabs OK. I was able to coordinate delivery of the L110s and pickup (gratis) of the L40s on the same day. During the road trip I had also arranged picking up an old version set of AR 2ax as well. Very productive speaker day.
I have since sent the 033s to their future home to be part of the L110 rebuild so now all I have is the cabs and xovers. I will keep an eye out for a set that has damaged cabs and hopefully marry these. I do like the look of L40 original grilles and hope to find a set.
Patience is a virtue.

Woofer
05-14-2015, 03:22 AM
…. you could always just use the boxes as Subs.