Upgrading L100 speakers

[quindecima]

I had in mind to upgrade my L100's. I thought to replace the tweets with 035ti or 044 and use4 a 4412 cross. Is this a feasable and good change?

[Robh3606]

I would use the 4312A crossover. It is closer to the original network and easy to impliment. You may be able to just add the inductor across the tweeter and add a cap across the original 3uf to bring it up to 3.3uf. The links are the schematics you need for the change if you don't already have them.

http://manuals.harman.com/JBL/HOM/Te...4312A%20ts.pdf

http://manuals.harman.com/JBL/HOM/Te...L100A%20ts.pdf

Rob

[porschedpm]

The 035Ti is not a drop in replacement tweeter for the L100 without some modification to both the cabinet baffle and the tweeter itself. However you can make a speaker that retains the vintage look of the L100 but has the updated sound of a 4412A. This is what I do to L100 cabinets that are in less than perfect cosmetic condition. It requires changing all the drivers and the crossovers. You shouldn't change just the tweeters or just the crossovers and tweeters. It's an all or nothing proposition. Also, for the sake of preservation I don't recommend modifying L100 cabinets that are in very good condition to begin with.

1) Remove the L100 drivers and crossovers. Do not remove the L-Pads. Coil up the wires to the L-Pads and place them out of the way. The L-Pads will not be used. Fill old tweeter screw holes with wood putty.
2) Remove old push-style input terminals and install modern input terminals.
3) Modify cabinet baffle to accept 035Ti (or 0354Ti-A) tweeter, See picture below.
4) Modify the 035Ti tweeter by cutting off one side of the plastic tweeter face. See picture below. Note this is a picture of the first conversion I did and I tried to make the cut to follow the outline of the midrange. On later conversions, I merely made a straight cut from about 1/4" to the right of one of the tweeter screw holes to about 1/4" to the left of the adjacent screw hole.
5) Install a 4412A crossover. This crossover does not use L-Pads.
6) Install the 104H-2 or 104H-3 midrange.
7) Install the 035Ti tweeter. I use a rubber gasket under mine. Check for proper fit and trim baffle or tweeter as necessary. New screw holes will have to be tapped.
8) Install the 128H woofer.

[grumpy]

as a thought: while carving up the cabinet, one could use a router to sink the tweeter
flush with the cabinet top... don't have to cut up the tweeter that way.

-grumpy

[L100t Owner]

What crossover should be built is using the stock L100 drivers?

Have any members designed better crossovers for the L100's? These seem to use the natural rolloff of the drivers (at least the high end of the woofer and midrange). Is this a good way to go?

Thanks,

Chris

[Robh3606]

You can always change the crossovers but just remember when you do it's not an L100 anymore. If you start band limiting the drivers you are going to change the voicing.

Rob

[Rusnzha]

I built charge coupled crossovers, replaced the LE5-2 with 104H-2 mids and put Parts express terminals on the back. It involved no butchery, it is still an L100, but at the same time, a whole lot more. Also got sonofagun grills. Too sweet!

[L100t Owner]

I built charge coupled crossovers, replaced the LE5-2 with 104H-2 mids and put Parts express terminals on the back. It involved no butchery, it is still an L100, but at the same time, a whole lot more. Also got sonofagun grills. Too sweet!

Do you have a schematic for the x overs? I want to keep the stock drivers, but do want to build some nice x overs.

Thanks,

Chris

[Rusnzha]

I would have to draw it by hand and scan it in. This will take some time, but I should be able to do it sometime over the weekend.

[Rusnzha]

Another thing that really helped was getting some "Acoustistuff" from Parts Express. I put a little bit in the mid-range compartment and a generous amount into the main box for the woofer. Also, the 123A-3 woofer is an upgrade from the 123A-1. Same personality, just better.

[Zilch]

Discussed before, but worth mentioning whenever the subject arises:

First L100 issue I'd address is mirror imaging, asymmetric in-line in lieu of clustered....

[Rusnzha]

Do you have a schematic for the x overs? I want to keep the stock drivers, but do want to build some nice x overs.

Thanks,

Chris

I drew the schematic for the charge coupled Xover, but I am having trouble posting it. Please PM me with a hotmail address or something and i will get it to you.

Russ

[Rusnzha]

Do you have a schematic for the x overs? I want to keep the stock drivers, but do want to build some nice x overs.

Thanks,

Chris

[L100t Owner]

Thanks. I am assuming 1 9v battery for each channel.

How does it sound? Looks like a modded L100 crossover keeping teh same values. it just seems to weird to not use inductors, just having trouble getting past that.

Chris

[Rusnzha]

A 9 Volt battery it is. They will last as long as the shelf life of the battery. There is no upper cutoff in the L100, these are simply hi pass for the mid and tweeter. I used Solen caps from Parts Express for the main caps. These are much better than stock, but not premium caps so I bypassed them with audiocaps also from Parts express.

The sound is much more clear and transparent with the modified crossover. This is really wierd, but even the low end seemed to tighten up quite a bit. I believe this is due to the better clarity of the bass harmonics in the midrange speaker.

I built them onto the same board as the stock crossover so they aren't the prettiest things in the world, but the appearance and the operation of the pots is unchanged.

If you are more comfortabe using a crossover with inductors, your best bet would be to follow porschedpm's suggestion go with something like the crossover in the 4412, but I'm not so sure it would sound like an L100 anymore if you do this. Good luck!