View Full Version : JBL L100 ... deference in sound between the speakers!

retro soulman
10-08-2013, 07:50 AM
hello all! i got a pair of l100 that i didnt use for years... some days ago i try them and i noticed a difference in sound between the two ... from one speaker which sounds quite bright in detail in high frequencies while the other quite Moodie ... The drivers of the 2 speakers are excellent ... may be the capacitors from crossovers;:dont-know:

Mr. Widget
10-08-2013, 08:11 AM
It is probably due to corroded or dirty L-pads. Fully rotate both L-pads on both speakers several times while the speakers are playing and see if it clears it up. If the speakers are playing you may hear drop outs in sound which will tell you they are dirty... if both pads smoothly increase and decrease their respective frequencies the problem is elsewhere... you may also have a blown driver.

A cap could be the problem, but this is the least likely.


10-08-2013, 08:13 AM
I would work the controls back and forth with a flat head screwdriver about 30 times each. Make sure tweeter is working on lower output cabinet. Then if that doesnt work maybe pull the tweeters and check separately. Also make sure woofer is not frozen. It should move smoothly back and forth. Could be capacitor, but would think tweeter would go out first. Also you could pull tweeters and reverse them into other cabinets and if still low output then you are probably right. Also check mids the same way.

retro soulman
10-08-2013, 08:33 AM
all drivers work fine !! ill check the lpads !

10-09-2013, 08:49 AM
I had one L-100 in the past where the 123A-1 alnico driver was weak. It played and had bass but something was happening in the mid-bass region, it sounded "thin" for lack of a better word.
Alnico magnets from this era are very sensible from over driving and I guess this one suffered from a blown amplifier sending DC.

A few years later I dissasembled it and notice the magnet was almost dead, also the voice coil showed signs of overheating, it was still good though and I changed the magnet (not an easy task) and it came back to normal.