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JBL L200 Studio Masters-Pics

Alobar said:
Yes Earl is right, the foam is attached to a thin piece of felt which is glued to the back cap of the driver and doesn't touch the diaphragm. The foam is supposed to be open cell of which I had difficulty finding so I made my own from a sponge like the tile guys use for cleaning grout. I cut a half inch of the sponge off with a sharp knife and then cut a circle pattern and glued it to the sponge. Then glued that to the back cap.

I know this sounds a bit backwoodsy but it did the trick and I couldn't hear any difference. I heard where the original foam may still be available from JBL so if you are doing this, and I think you probably should at some point, then I would definitely try to source the OEM stuff.

Using a very sharp kitchen knife.. (wife does NOT know!)

View attachment 1248699

I used felt from a turntable mat I wasn't going to ever use, but should be able to find this stuff easily..

View attachment 1248700

Felt/foam glues to inside of the back cap of the driver, felt to the back...
Be cautious as can be about both the screws and the crimp on forks as those are ferrous and will want to jump right onto that fragile diaphragm! Hence why I replaced both diaphragms with new ones (Radian 16 ohm). I only dinged one but I decided to change both diaphragms out so as to be a matched pair.. I got lucky that these Radians sound great, perhaps even better than the OEM and go for only $80 instead of $160 ish on eBay..
View attachment 1248701
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I have foam left over from when I restored my Time Windows. It's air filter foam but also sold as grill foam. I'll post a closeup pic when I can and see if you gents think this will work.
Glenn
 
GD70 said:
I have foam left over from when I restored my Time Windows. It's air filter foam but also sold as grill foam. I'll post a closeup pic when I can and see if you gents think this will work.
Glenn
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Yeah that would probably work fine.. My test is if you can blow and suck air through it easily it should be good...
 
I used the carpet padding that looks like "head cheese." I don't remember the density.

It would be interesting to compare the different types of possible replacement foams with an RTA and I would bet they all have their own sonic signature.
 
toddalin said:
I used the carpet padding that looks like "head cheese." I don't remember the density.

It would be interesting to compare the different types of possible replacement foams with an RTA and I would bet they all have their own sonic signature.
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Maybe.. I tried to use something that was as close to the original stuff as I could get in my one horse town.. I read where it is basically to prevent ringing off the cap which makes sense so I don't know if sonic signature would be accurate. If that is true, and there is some sort of sonic sig, then the foam/felt ain't doing its job JMHO..
 
I do remember someone mentioning using felt in the cap at one point - since it would not degrade,
but don't expect me to backtrack through 10 years of reading Lansing Forums to find it now!
I have a different kind of foam in the drilled caps for my ALTEC horn drivers.
 
Cool find Glenn....and cheap!..lol. How this stuff finds you is crazy. But I do see a quandary. You have east coast sound and now...west coast in your humble abode.

Which speaker is going to make the other cry first?!!....lol. Congrats....hope they turn out well for ya.
 
Alobar said:
I think that stuff looks like it will do nicely. I would check the thickness of the old foam and try to match it without going thicker so as to risk the foam making contact with the diaphragm. Probably 2 layers of the 1/4 inch material would be fine. Don't forget to use some felt behind the foam as well. .
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Thanks for the advice! I can't wait to get going on these beasts!
 
centsless said:
Cool find Glenn....and cheap!..lol. How this stuff finds you is crazy. But I do see a quandary. You have east coast sound and now...west coast in your humble abode.

Which speaker is going to make the other cry first?!!....lol. Congrats....hope they turn out well for ya.
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Thanks cents!

Ha! The first tears will be lifting these!
It seems various conversations with people lead to "what music do you like", which leads to "what are you listening to it on", which leads to gear discussions, which leads to...
word spreads about my hobby, as well as leads from Aker's like this one. I'm not really looking too hard for speakers, but when something like this appears, well I'm not going to pass it up, plus I've been wanting a new project to dive into.

Cheers, Glenn
 
GD70 said:
So the side grills are glued in from what I can tell. They wouldn't budge. Once I get into the cab restoration, I'll cover the fabric for protection.
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Yes they're glued in and if you try to remove them do so carefully because the frame breaks easily.
 
They look really faded (although perhaps it's dust): Depending upon the color you desire, you might clean them with a damp sponge or carpet cleaner, let them dry, then hit them with some fabric spray paint.
 
Zonker92 said:
They look really faded (although perhaps it's dust): Depending upon the color you desire, you might clean them with a damp sponge or carpet cleaner, let them dry, then hit them with some fabric spray paint.
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Yeah, I'll take some better detail pics and post. In person, they look pretty decent.
 
Well I finally got a chance to do a test listen to these beasts. I used a spare JVC A-X77 integrated rated @ 90wpc, and my ipod.
HOLY SHEEEiTTT! I let them play at low volume for a bit to warm up, let the juice go through the crossovers. I have no idea when these were last in use. After 10-15 minutes I increased the volume and just WOW!
Now they are sitting next to each other as shown in the earlier pics. So the environment is not ideal, but none the less, these are spectacular in their all original state. I'm not doing anything to the crossovers. The highs are crisp, and very detailed. The bass is tight but deep. Those 15 inch woofers were barely moving! Damn!
So the only thing I plan to do is pull the tweeters to replace those foam dampening disks behind the domes, restore the cabs, and get the repro grills. Also does anyone have closeup pics, and a source for the correct grill badges or spares they could sell to me? The promo pics on the web are not very clear and I couldn't see what they should look like.
I did a video, and will post it in the video thread in a bit.
Cheers, Glenn
 
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