JBL recone parts origin question

[spkrman57]

I have now run across a 2nd driver that was reconed with authentic JBL recone parts that have a problem with intermittent voice coils.

The 1st time it happened, the recone (E-130) was done by a expert with JBL drivers and the problem did not show up for him as he was running SS amp to break them in for me. I use tubes which have no DC offset and no current flow at no signal condition. I say that because the problem will not show up if you have sufficient current through the voice coil which seems to jump across the very small hairline crack in the voice coil windings.

I would be listening to the drivers with music playing and all of a sudden it would just quit playing like you disconnected the wires leading to the drivers. Since I use tube amps with output transformers, I took a 9 volt battery and tapped the driver terminals checking for continuity(DON'T do this with SS amps!!!) and after I heard the driver click with the battery connection the music resumed playing again. It would quit again after 10 - 20 minutes and I repeated the process again with the same results.

The 2nd driver was a K120 that was reconed(reconer unknown), I was assured it was professionally reconed with authentic JBL parts. The drivers were installed in wood horns that a friend of mine borrowed to see if he liked the sound or not. He claimed that he and his wife were listening to the music and it just quit all of a sudden. He too uses tube amps.

I received the drivers back the other day and measured the DCR. One of them was 6.8 ohms and the other 44.6 ohms. I took the battery and tapped the terminals and remeasured the DCR which was 6.7 ohms at this point. I knew at this point it was deja vu all over again!

What companies/countries are suppliers for JBL recone parts anymore???

This really hurts us audiophiles who use vintage JBL drivers. I can't afford to keep reconing drivers due to bad parts.

Just letting off steam!

Regards, Ron

[macaroonie]

Are you sure its not a dry joint where the new cone was installed , or where the tinsel leads are soldered to the coil ends on the cone. The latter is more likely due to the enamel on the coil contaminating the joint. The flat ribbon is pretty sturdy.

Just thoughts

[spkrman57]

The E-130 I had done a year or two ago was done by a experienced member of this forum who I have absolutely no doubt of his background/knowledge of JBL drivers.

It's interesting to note on both drivers, that the intermittent problem only shows up with low powered application. If enough wattage is applied the problem seems to not happen the same way.

Of course with my speaker systems using very high efficiency drivers are usually running with less than a watt/chnl for my normal listening levels.

Ron

[robertbartsch]

Have you isolated the issue to the reconed drivers? You could have an issue with speaker wires, crossover, or amp, I suppose.

[spkrman57]

In fact I have even isolated things down to the braided leads going to the voice coil.

I have no doubt that this is the result of poor QC on the recone kits.

Like I said before, both units(E-130/K-120) would become inoperative after approx 20 mins of playing. They would just quit while the same model driver on the other chnl would play just fine. I would tap a 9 volt battery to the speaker terminals and the drivers would start playing again just fine. This would last for a short while and the process would repeat again.

On the E-130 driver, it was reconed a 2nd time and it performs just fine. On the K-120, it is being used in a midbass horn and I have informed my friend who is borrowing the horns and drivers how to keep them playing long enough to see if he likes the horns. If he does, there is a option for a pair of EV 12" drivers that would also work in those horns he could get from one of our friends.

Ron

Have you isolated the issue to the reconed drivers? You could have an issue with speaker wires, crossover, or amp, I suppose.

[SMKSoundPro]

Sounds like a tinsel lead problem. I had a pair of 2226's that exhibited that same phenoma. When playing "Normal" volume level, everthing was fine. WHen I turned it down to talk to Lisa, one 2226 just wasn't there.

We pulled the driver and swept it on the bench. We found that the tinsel lead was not making a good solid electrical connection to the terminal post.

I clamped the tinsel lead to the post with a pair of hemostats, I hide here at the bar, and re-soldered that connection. Fix, fix!

I pulled the other 2226 and found the same thing starting to happen. I re-soldered that one also. We then loaded all of the rig and played the gig in Fairbanks with no problems. I sure am glad we "found" the problem before we got it all setup and had egg on our faces!

Check the tinsel lead connection. It may be attached, but not always electrically connected.

Scotty.

[Allanvh5150]

As already said, the tinsel wires are commomnly known to have bad connections. You may ne able to just resolder the terminals. I have also seen them break where they run through the cone.

Allan.

[4343]

Sounds like a tinsel lead problem. I had a pair of 2226's that exhibited that same phenomena. When playing "Normal" volume level, everything was fine. When I turned it down to talk to Lisa, one 2226 just wasn't there.

We pulled the driver and swept it on the bench. We found that the tinsel lead was not making a good solid electrical connection to the terminal post.

I clamped the tinsel lead to the post with a pair of hemostats, I hide here at the bar, and re-soldered that connection. Fix, fix!

I pulled the other 2226 and found the same thing starting to happen. I re-soldered that one also. We then loaded all of the rig and played the gig in Fairbanks with no problems. I sure am glad we "found" the problem before we got it all setup and had egg on our faces!

Check the tinsel lead connection. It may be attached, but not always electrically connected.

Scotty.

Had the same thing happen to one of my D-131's after letting a friend play guitar (softly) through the pair. Sounded great, but a few weeks later when I hooked them up to the tri-amp system again, one was dead. Measured infinity on the ohmmeter! I was bummed, to say the least...

While refoaming my L-110's, I used the dead driver as a weight to hold the gaskets down while the glue dried, and the next day while running tones through the LE111, I decided to try the D-131 again, still dead. While pulling on the tinsel lead, it came to life for a second, so it made a trip to the solder station, and it's back in biz...

[SMKSoundPro]

Before thinking that a driver is dead, try your test leads on the tinsel leads.

[subwoof]

I would actually heat the black goop over the eyelet, remove it and then remove / wick the opening so a new tinsel lead can be installed.

The flat wire that goes into the former sometimes doesn't tin correctly and fails. New tinsel leads and the CORRECT SOLDER is required to fix.

I did this on top of a bar once with a flashlight in my teeth. Happened to have a dead speaker in the car with good leads so I got the bass player's rig back up and running and didn't have to buy any drinks all night.

Had to leave kinda quick because I spent too much time "explaining" electronics to his girlfriend..:o)

sub

[4343]

Before thinking that a driver is dead, try your test leads on the tinsel leads.

Bummed! The push clips were OK, but the joint on the outside end of the tinsel lead was COLD...