View Full Version : JBL LX3-1 Crossover Question

C56 Dorian
03-06-2017, 09:47 AM
Hello - I've just acquired a pair of C56 Dorian cabinets that contain the S5 driver and crossover package (LX3-1 x-over, LE 30 HF, and LE 10A LF drivers). They are functioning well considering their age and the oxidized state of the LE10A surround. I've found a technician that will be able to reform the LE10A here in Saint Louis. However; I see by reading this forum that there are no real re-coning options for the LE30 HF driver. I would like to bring this driver up to speed as well. Is it possible to replace the LE 30's with the standard LE 20's that originally came with the Dorians? Or would I need to replace the x-over with the LX10? I'm new to the world of electronics so I'm not sure how to read the schematics of the LX3-1. I am aware that most JBL x-overs were designed for specific drivers, bit I wasn't sure if I could "bend" the rules in this case. Any guidance here will be much appreciated.

By the way, this is my first post here and I would like to thank everyone on the forum for sharing their profound knowledge about the world of JBL! When I was younger I worked in a hi-fi shop in Peoria, IL that had been a JBL dealer since the 50's. We had a metrogon in the shop, and various other vintage JBL loudspeakers… In short, I was hooked. These Dorians are taking the place of my little 18Ti's (it's the old 044 tweeter fail that you all know so much about…) and I can't wait to get them refreshed and ready of another 50 years! Thanks in advance and take care.

Earl K
03-06-2017, 12:21 PM
If you replace the le30 with either the le20 or the le25, then the result becomes ( more or less ) an L77.

The L77 uses this network ;


I'd suggest you build your own.

The following ( LX3-1 ) doesn't look adaptable enough ( IMO ).



C56 Dorian
03-07-2017, 10:35 AM
Thank you for looking into this for me Earl K. - I appreciate your expertise. These schematics confirm my suspicion that this x-over is specific to the S5 system. I will start to educate myself about the world of JBL x-over design, until then I just hope those L30's keep working! Thanks again and take care.