Help with L100 needed

[roivett]

I recently rescued a pair of L100 Century speakers from the trash bin. They were not working very well when I got them home. The 123A-1's seemed to be working, the LE-25 tweeters had the dust cones pushed in but were working (sponge rings in good shape though), and the LE 5-2 mids will not produce any sound at all. I have removed the XOVRs and one of the pots will not turn. Cabinets are in rough shape as you would expect. Any thoughts on a cure for the mids? I would love to bring these back to life to compliment my Bozak 302A's. Any suggestions would be welcome.

Thanks, roivett

[badman]

First thing to do is to find out if the drivers are bad. Run a multimeter on them, they should read something around 5 ohms DCR (neighborhood of), if so, you're in good shape for a quick hookup to an amp, playing quietly, to see if the drivers are bad and it's just the XO (which seems entirely possible). You may simply need to replace the L-pads in the XO and be all set.

[roivett]

Thanks Badman for the advice. I measured all three sets of speakers with a miltimeter today. Both 123-1's read 4.5/4.6, tweeters measure 0.0 (no continuity)/4.4, and mids measured 0.0/0.5 ohms. Not able to get to the XO yet. I have one off but need to take the second out after I remove the foilcap/nameplate. Any suggestions?

Thanks Again,
roivett

[Eaulive]

Thanks Badman for the advice. I measured all three sets of speakers with a miltimeter today. Both 123-1's read 4.5/4.6, tweeters measure 0.0 (no continuity)/4.4, and mids measured 0.0/0.5 ohms. Not able to get to the XO yet. I have one off but need to take the second out after I remove the foilcap/nameplate. Any suggestions?

Thanks Again,
roivett

0 ohms is shorted, or perfect continuity, either way they're fried.
I don't think it's economical to repair, unless you have some sentimental value of some kind towards them.
The 123A-1s seems to be allright though, you could sell them as parts.

[roivett]

0 ohms is shorted, or perfect continuity, either way they're fried.
I don't think it's economical to repair, unless you have some sentimental value of some kind towards them.
The 123A-1s seems to be allright though, you could sell them as parts.


Thanks, that is what I thought. I have no sentimental connection, actually they belonged to a high school band for several years, so you can only imagine the abuse they must have been through. Cabinets are in terrible shape too with cracks and pieces missing. The LE 5-2 mids I see on ebay are really quite expensive but I see an occasional pair of LE25's at a fair price from time to time. I think I will keep a lookout for some drivers and work on moding my Bozak 302A's for now. I still think the L100 would be a nice match for the Bozaks.

Roivett

[dprice]

Recones for the mids and tweets are near $100 each, replacements on Ebay are typically $50 and up depending on condition (unless trashed). If the cabs and crossovers were perfect, it might be worth the repairs. But that isn't the case. You pulled them from the trash. Harvest what you can and be proud you saved something from the landfill...at least for a few more years.

By the way, the 123A-1 in a 3-5 ft^3 sealed box is a nice place to start if you have a DIY itch to scratch.

[Zilch]

OR:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=245-325

[Eaulive]

OR:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=245-325

The one on the left is the PT waveguide from the MRX series with a 2408H?
Honestly, how do you compare this with the original L-100?

I have a itch to scratch... but no money to spend :(

[Zilch]

PRX, actually, and they're $6 apiece, if I recall correctly. JBL does not call them waveguides, and they're not PT. They are definitely constant directivity, however, closer to Geddes designs. Drivers are Selenium D220Ti, and I've just worked out the crossover for that combination. Use the smaller and lighter D2500Ti-Nd if you're willing to spring for a bit higher cost. PC boards are available; PM for details. 2408H is appropriate, too, or 2414H(-1) but somebody else'll have to develop the filters for those.

The Dayton KD Trap cab kits are ~1.6 cuft. as shown, but can be expanded to ~2 cuft. by moving the baffle forward. Shipping's free on pairs of them from Parts Express. Not world-class Baltic birch, but serviceable, and can be finished nicely. See Johnaec's floor monitor project on this site.

They can be ported front or rear for L100 bass and greater power handling, but they're mighty nice closed box, too. You'll have to build them and tell everybody how they sound compared to L100/4311(B). I doubt you will be disappointed by their performance, however you might characterize that, sonically; they do not suck.

On the right is AC18 in AR4x cab. Both of these projects are shown in the EconoWave thread on AK, along with the obligatory flood of their respective response measurements.... ;)

Color key: On axis = Red, UP = Org, Yel, Gry, Aqu, DN = Grn, Blu, Vio, Cyn

[Eaulive]

PRX, MRX, same 354267-001 horn. Don't like the shape but at this price I could get used to it :)

However, I think you could do better with the 123A-1 rolling off at 200Hz.
It will definitely sound whimpy next to the L-100 which was having too much bass, granted, but some like it :applaud:

[Zilch]

However, I think you could do better with the 123A-1 rolling off at 200Hz.Measurements are MLS and roll off at the frequency specified in the legend.

Gotta use a different methodology to show the LF response.

[Trust the Zilchster; it is there.... :D ]