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View Full Version : HELP! Technical information on JBL 104H drivers


GenPatton
11-03-2010, 09:01 PM
Hello everyone. I would really appreciate some help on this. I will try to make this as brief as possible. I have a pair of Ti-120's that use the JBL 104H mids. A speaker clinic looked for Polypropylene replacement drivers as one of the cones was pushed in. They ended up finding a paper cone replacement, the 104H-2. To make matters worse they mounted the cones on a pair of LE5-2 baskets. (L100 midrange baskets) He wanted me to try these as before I purchased them. Thank god I did as they did not sound right at all. Now I have two issues here. One really important one is why the heck would he use the LE5-2 baskets and magnets? Would that not effect the quality of sound, efficiency etc? or am I wrong and he knew what he was doing.
Second is it is very hard to find the polypropylene drivers. He has offered to recone my mids with the paper cone drivers, but after this experience I am a little worried. He has also asked that I "burn in" the LE5-2 baskets with the 104H cones by listening to them for twenty hours. I will do that but I am not sure. Any comments/suggestions would be most appreciated as I love these speakers. I have them hooked up to a tube amp and am so upset that they sound like this now. Thanks in advance for your help.
Three pics are included. The original polypropylene 104H drivers, the paper cone 104H2 and the LE5-2 Baskets he gave me with the 1042 paper cones.
DavidF
11-03-2010, 09:33 PM
Sorry, just me but I am not sure what you are asking. You have one 104H driver that has a pushed-in voice coil dome but otherwise functional? Yes, then change the dome only. The original aluminum piece is no longer stocked by JBL but chances are there are many still out there in service shops.

Not sure what a "speaker clinic" means. Likely a repair shop?
GenPatton
11-03-2010, 10:37 PM
Sorry, just me but I am not sure what you are asking. You have one 104H driver that has a pushed-in voice coil dome but otherwise functional? Yes, then change the dome only. The original aluminum piece is no longer stocked by JBL but chances are there are many still out there in service shops.

Not sure what a "speaker clinic" means. Likely a repair shop?

Correct, I have one 104H that has a pushed in voice coil dome. But no one seems to have the right dome. I also assumed that since the midrange drivers are 27 years old they might need a re-coning. Correct, speaker clinic is a repair shop. Sorry for the confusion.
So your saying that other than the voice coil dome a 104H that's 26 years old is fine? Just curious.
DavidF
11-04-2010, 09:13 PM
Correct, I have one 104H that has a pushed in voice coil dome. But no one seems to have the right dome. I also assumed that since the midrange drivers are 27 years old they might need a re-coning. Correct, speaker clinic is a repair shop. Sorry for the confusion.
So your saying that other than the voice coil dome a 104H that's 26 years old is fine? Just curious.

I have three 104h poly drivers of the same vintage and original cones. One unit had a small section of glue on the surround let go. I reglued and has been fine since. I have no worries about their functionality just because of age. It is arguable that the crushed dome may cause some audible wrinkles in the response of the driver. Of course if you put in the 104H-1 paper model you will most definately cause some audible wrinkles in the response. It is quite a different driver.

If mine I would try to fix the dome but not lose sleep over it.