Some questions about the 4412s

[Theopholis]

Hi all. Please excuse me if these questions have already been answered. I tried using the “Search” function for quite some time, but could not find the answers to these questions.

I’m building some 4412 clones in a wood shop class I am taking and I have a few questions.

1. What wood types and stain colors were available on the veneer?
2. I’m thinking about altering the cross-over by biasing /charge-coupling. I know this was done for the L250’s. Was this ever done on the 4412s? Do you think it would make a noticeable difference? Does anybody have any schematics? (If not, I think I might be able to figure it out myself.)
3. I bought 104H-2s instead of 104Hs (I had planned on making L250 clones originally). I’ve seen the Brüal and Kaœl curves, and they look VERY close. Any need to alter the cross-over? Or just live with it? Actually, it would be really nice if somebody could explain how to read those charts and how to use the information.
4. I bought 128s that need to be re-coned. I found one place on E-Pay that sells recone kits, but they don’t appear to have Aquaplas on them. Does anybody know of any other place that sells recone kits? Or sells Aquaplas? How much of a difference will it make if I don’t Aquaplas the woofers?
5. I see some company is making copies of the 035Ti’s. Has anybody tried them? Are they any good? Is there a way of telling the difference between real JPL and the copy?

Thank you in advance for your help.

Dave

[kelossus]

Hi all. Please excuse me if these questions have already been answered. I tried using the “Search” function for quite some time, but could not find the answers to these questions.

I’m building some 4412 clones in a wood shop class I am taking and I have a few questions.

1. What wood types and stain colors were available on the veneer?
2. I’m thinking about altering the cross-over by biasing /charge-coupling. I know this was done for the L250’s. Was this ever done on the 4412s? Do you think it would make a noticeable difference? Does anybody have any schematics? (If not, I think I might be able to figure it out myself.)
3. I bought 104H-2s instead of 104Hs (I had planned on making L250 clones originally). I’ve seen the Brüal and Kaœl curves, and they look VERY close. Any need to alter the cross-over? Or just live with it? Actually, it would be really nice if somebody could explain how to read those charts and how to use the information.
4. I bought 128s that need to be re-coned. I found one place on E-Pay that sells recone kits, but they don’t appear to have Aquaplas on them. Does anybody know of any other place that sells recone kits? Or sells Aquaplas? How much of a difference will it make if I don’t Aquaplas the woofers?
5. I see some company is making copies of the 035Ti’s. Has anybody tried them? Are they any good? Is there a way of telling the difference between real JPL and the copy?

Thank you in advance for your help.

Dave

1. Walnut Veneer which was oiled with a linseed/turpentine mix. Not stained as far as I know and this was the only option available.
2. If I was building clones I would certainly bias the original crossover. I haven't come across a CC'd schematic for them but it is simple enough to work out.
3. 104H-2's are the correct mid-ranges. The 104H's have poly cones and were used in the later TI series e.g. 120TI, 240TI, 250TI.
4. I wouldn't consider anything but original JBL recones, they are still available. http://reconingspeakers.com/product/...h1-recone-kit/
5. Yet again I wouldn't consider anything but genuine JBL gear, try and pick up 2nd hand pair of 035TI or 052TI. There are millions around. Consider replacing the foam damping plug underneath the Titanium diaphragm as it would be likely toast.

[ltngstruckfirst]

1. I’m thinking about altering the cross-over by biasing /charge-coupling. I know this was done for the L250’s. Was this ever done on the 4412s? Do you think it would make a noticeable difference? Does anybody have any schematics? (If not, I think I might be able to figure it out myself.)

If you get this figured out, I would certainly be interested in seeing the schematic.
BF

[Theopholis]

1. Walnut Veneer which was oiled with a linseed/turpentine mix. Not stained as far as I know and this was the only option available.
2. If I was building clones I would certainly bias the original crossover. I haven't come across a CC'd schematic for them but it is simple enough to work out.
3. 104H-2's are the correct mid-ranges. The 104H's have poly cones and were used in the later TI series e.g. 120TI, 240TI, 250TI.
4. I wouldn't consider anything but original JBL recones, they are still available. http://reconingspeakers.com/product/...h1-recone-kit/
5. Yet again I wouldn't consider anything but genuine JBL gear, try and pick up 2nd hand pair of 035TI or 052TI. There are millions around. Consider replacing the foam damping plug underneath the Titanium diaphragm as it would be likely toast.

Thanks for the info! Especially the re-coning site. The place I was going to buy my kits from didn't show the back of the cone, and I couldn't tell if it had the Aquaplas on them or not. This one clearly does.

[Theopholis]

[/LIST]


If you get this figured out, I would certainly be interested in seeing the schematic.
BF

Will do! I figure to have this done in about a month.

[Doctor_Electron]

Quote:

"1. Walnut Veneer which was oiled with a linseed/turpentine mix. Not stained as far as I know and this was the only option available."

50% Pure gum turpentine 50% Boiled linseed oil . Be careful with the rags - spontaneous combustion hazard

I dig your project, awesome.

-de-

[Doctor_Electron]

The description left out two items, 1). The alignment cylinder 2). The correct adhesive

Requires also that you have a very precise and driver(s) specific, non-magnetic gap gauge. Using all non-magnetic tools is strongly recommended; the mag flux will pull a standard ferric-based tool out of your hand so quickly and forcefully you won't believe it. And it's headed straight into expensive real estate if it happens.

I worked at an authorized JBL Pro Service center. I wanted to learn re-coning.

No black magic (so it had seemed before seeing the process), Re-coning is easier than refoaning. With the sole exception of removing old "glass" (plas?) from the frame. They must get that stuff from Planet Krypton. TOUGH !

It is an enjoyable and rewarding experience especially with fine JBL drivers, bringing them back to life. Enjoy !