Rebuild JBL Century 100's?
- Thread starter BuzzK
- Start date
Register to hide this ad
BlackScholes
Active Member
Nowhere in this typical tired bashing of the L100s do I see an answer to the OPs question..
Yes, because the crossover is probably the weakest point in the L100, upgrading it would probably give you SOME gains. However, a better option for better sound quality if you were interested would be to sell the L100s and use the $500 or so you'd get for them to purchase a pair of 4410s or 4412s. You could use the leftover cash to upgrade the crossovers in the 44XXs and you'd end up with a much better speaker than the L100 would ever be.
kconnor
Well-Known Member
If you want to keep your L100’s and improve the sound try this link. Troels Gravesen is one of the top do it yourself speaker/ crossover designers around. He has designed many well-regarded speakers for the DIY community. You can trust his opinion.
http://www.troelsgravesen.dk/JBL_L100.htm
http://www.troelsgravesen.dk/JBL_L100.htm
Parts Express also has a crossover kit for the L100. It's a re-design including better parts and inductors and supposedly corrects some midrange peakiness in the original design.
I have no experience with this kit, just an FYI.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-896
I have no experience with this kit, just an FYI.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-896
stereofanboy
Addicted Member
Ye gods, $278, and you have to assemble them!
Heck, you can't even buy quality caps for $278....that's pretty fair depending on components used
jblmar
JBL & marantz
Last edited:
70salesguy
Only 99 easy payments!
You guys need to get some new material.
Copa1934
My ears are bleeding
My L88's are like that too, woofer wide open. On the other hand, that's truly amazing for a 12" woofer, but not the best application.
This aspect of vintage JBL speakers really makes me wonder at times about their thinking, i.e. were the drivers "that good" (to JBL of course) to warrant NOT using more elaborate xovers? I read put downs a lot about other brands of speakers, yet JBL went with rather lean xovers in many early speakers. Other speaker brands would be chided for this.
Zonker92
All shiny and chrome
I recapped my 4311s with Daytons bypassed with Thetas, using the original values. It really didn't make much different to my ears. Here is a thread on that exact job, with various approaches:
http://audiokarma.org/forums/showthread.php?t=106180 (4311Bs = same basic design)
The drivers and cabinets are very nice, but the crossovers are crude. I read that the L100 was following the sound of the 4311, which in turn followed the sound of the 4310, which in turn copied a popular Altec monitor, all with a peaky midrange and too gentle of a woofer rolloff. So it was apparently a deliberate choice to make them sound that way.
The Troels/Jantzen/Parts Express crossovers are supposed to be very nice, but I wish he would publish the schematics; unless you buy the kit, all you can get are ones without the values of each component.
If you don't like the sound, another good crossover upgrade is supposed to be the one here from Murphy. I plan to use this one my 4311s. A lot people plug the ports, too, for less of a hump in the bass.
http://forums.audioholics.com/forums/showthread.php?t=25014
http://techtalk.parts-express.com/showthread.php?t=220629&page=2
http://audiokarma.org/forums/showthread.php?t=106180 (4311Bs = same basic design)
The drivers and cabinets are very nice, but the crossovers are crude. I read that the L100 was following the sound of the 4311, which in turn followed the sound of the 4310, which in turn copied a popular Altec monitor, all with a peaky midrange and too gentle of a woofer rolloff. So it was apparently a deliberate choice to make them sound that way.
The Troels/Jantzen/Parts Express crossovers are supposed to be very nice, but I wish he would publish the schematics; unless you buy the kit, all you can get are ones without the values of each component.
If you don't like the sound, another good crossover upgrade is supposed to be the one here from Murphy. I plan to use this one my 4311s. A lot people plug the ports, too, for less of a hump in the bass.
http://forums.audioholics.com/forums/showthread.php?t=25014
http://techtalk.parts-express.com/showthread.php?t=220629&page=2
Last edited:
BuzzK: I'm curious as to what you would hope to obtain by doing the crossover upgrade. Are your L100's in good shape as they are?
I've had two pair of 4311's, two pair of 4312's, and one pair of L100's. I've always felt that, to my ears at least, the midrange from all of these speakers was pretty good but one had to be careful with the tweeter, especially on the 4312's. As far as bass is concerned, none of them had quite enough for me.
In a last-ditch effort to get the kind of sound I was looking for, I purchased a Polk PSW-505 subwoofer and added that to one of my systems using a Yamaha receiver and a pair of 4312's. I kept all of the level controls on the speakers right at their midpoint and I did the same with the subwoofer's crossover and volume controls.
The results, at least to me, were pretty damn good! I'm very happy with this particular system and I find that I use it almost exclusively for vinyl. The midrange is still top-notch, but now I have some "warmth" to the music, especially the vocals. In combination with keeping the tweeter levels down somewhat, I find the sound to be just right for most of my vinyl. Occasionally I'll have to make a minor adjustment here or there on certain records.
The reason I bring all of this up is because, for $199 (amazon.com), I improved my system to where I wished it to be with a minimum of fuss. I've always been skeptical of the crossover upgrades. Oh, I'm sure they work, and probably work well in some cases, but for "older ears," I'm not sure if one could tell much difference from the original sound of the speakers.
Just a thought.
I've had two pair of 4311's, two pair of 4312's, and one pair of L100's. I've always felt that, to my ears at least, the midrange from all of these speakers was pretty good but one had to be careful with the tweeter, especially on the 4312's. As far as bass is concerned, none of them had quite enough for me.
In a last-ditch effort to get the kind of sound I was looking for, I purchased a Polk PSW-505 subwoofer and added that to one of my systems using a Yamaha receiver and a pair of 4312's. I kept all of the level controls on the speakers right at their midpoint and I did the same with the subwoofer's crossover and volume controls.
The results, at least to me, were pretty damn good! I'm very happy with this particular system and I find that I use it almost exclusively for vinyl. The midrange is still top-notch, but now I have some "warmth" to the music, especially the vocals. In combination with keeping the tweeter levels down somewhat, I find the sound to be just right for most of my vinyl. Occasionally I'll have to make a minor adjustment here or there on certain records.
The reason I bring all of this up is because, for $199 (amazon.com), I improved my system to where I wished it to be with a minimum of fuss. I've always been skeptical of the crossover upgrades. Oh, I'm sure they work, and probably work well in some cases, but for "older ears," I'm not sure if one could tell much difference from the original sound of the speakers.
Just a thought.
JBL Cenutry L100 Crossover's hidden components in Wax REVEALED
The photo here is a crossover from what I think may be the first run of the JBL L100. Put it in the oven for 20 minutes at 220 degrees (covered most of the components with a three layers of aluminum foil, leaving the cardboard tube exposed) This was just enough time and heat to melt and pour out the wax, remove the 3 components, and not harm anything. I picked up a pair of these Century Speakers for just $50. Damaged cabinets, one tweeter has a tear and only one grill cover, but am happy to get them for that. The tweeter's are just barely audible on both when wired through the crossovers. Nothing wrong with at least the one I took out so far. Hooked it up directly as well as the mid and woofer, and they all sounded at a level as one would expect. But when all are hooked up to the crossover, the tweeter is weak. The frequency controls work fine. Wiring/Electronics has always been a weak point for me, so could anyone tell me what may be the problem of the barely audible tweeters? I really do not care to invest in a new pair of crossovers. Surely JBL could not have been as negligent as some have claimed when designing this crossover. Would like to remedy the weak tweeter problem with minimum investment. Are there any credible solutions out there?
The photo here is a crossover from what I think may be the first run of the JBL L100. Put it in the oven for 20 minutes at 220 degrees (covered most of the components with a three layers of aluminum foil, leaving the cardboard tube exposed) This was just enough time and heat to melt and pour out the wax, remove the 3 components, and not harm anything. I picked up a pair of these Century Speakers for just $50. Damaged cabinets, one tweeter has a tear and only one grill cover, but am happy to get them for that. The tweeter's are just barely audible on both when wired through the crossovers. Nothing wrong with at least the one I took out so far. Hooked it up directly as well as the mid and woofer, and they all sounded at a level as one would expect. But when all are hooked up to the crossover, the tweeter is weak. The frequency controls work fine. Wiring/Electronics has always been a weak point for me, so could anyone tell me what may be the problem of the barely audible tweeters? I really do not care to invest in a new pair of crossovers. Surely JBL could not have been as negligent as some have claimed when designing this crossover. Would like to remedy the weak tweeter problem with minimum investment. Are there any credible solutions out there?
Attachments
Zonker92
All shiny and chrome
Weird. I bet those crossovers are not original. Those yellow caps look to date from the 1980s.
I would test each resistor after lifting one leg of it. I would pop off the backs of the L pads and clean them with spray contact cleaner and examine them and test their resistance. I would replace both caps. And I would make sure all the connectors are shiny and tight.
I would test each resistor after lifting one leg of it. I would pop off the backs of the L pads and clean them with spray contact cleaner and examine them and test their resistance. I would replace both caps. And I would make sure all the connectors are shiny and tight.
Rick Vestal
Have a nice day and duck!
It's right... Poking around there's multiple people with identical components...
