044Ti questions/Help needed

[SEAWOLF97]

I ASSUME that the plugs are there to stop ringing ???

some of those posts speculate that the foam supports the dome, I have doubts. Think its got to be there for damping.

so I was doing some idle reading on the forum and came across the definitive answer to my above posted speculations.

...The best sounding model was the Jubilee and the weakest one was the original L250. From the 250Ti through to the Jubilee, this sonic difference was pretty small with each newer model sounding incrementally better.

it is true that there is a foam damping plug under the titanium dome. It does take a set after time and doesn't damp as well. Changing the plug usually brings the tweeter behavior back to original conditions. ...

[SEAWOLF97]

.
https://www.ebay.com/itm/162909599587

JBL 035Tia, 035Ti Tweeter dampining foam pads (Pair will do 2) L3,L5, L7, Others
Price:US $29.99

The foam damper at the back of all the JBL 035Ti / TIA (possibly others) dome dissolves (see last photo), and they make a "Pinnnnggg" rather "QueinggGGggggggg" - These tweeters really need some damping. These foam pieces come with a new diaphragm kit from JBL however the kit is no longer available and discontinued. You get 2 small hard foam pieces and 2 large soft foam pieces as shown in the kit. You simply remove the front screen, remove the 4 screws that holds the diaphragm to the magnet. Remove the diaphragm and clean the old foam out. Make sure you clean out the magnet gap. Use 2 sided tape or glue to install the new foam pieces in place as shown in the photo. The small one goes under the larger one. Bring your JBL's back to the way they are supposed to sound and not the awful shrill sound they get when the old foam stops working.

but at least you can get a 3 year protection plan

3-year protection plan from SquareTrade - $8.49

WOW ..I must have hundreds of thousands of dollars just sitting in old shipping boxes (at $29.99 per chunk)

[grumpy]

I'd think if a person had the skills to remove the diaphragm in one piece, that locating appropriate foam
wouldn't be too tough... but having a turn-key (presumably) foam solution will probably make a few folks
feel better about removing the goo themselves. Shoot, I paid a silly amount for LE25 rings for convenience
sake... but it wasn't $30 either. The market will sort it out

[LHorn]

Hello everyone..I realize this is an old thread but there's one thing I cant grasp on this procedure. On reassembly..how do you get the voice coil centered? I have done LE14H-1's no problem..but I dont see where any adjustment is on the 044Ti's. I have eight of these to do eventually.

[SEAWOLF97]

Hello everyone..I realize this is an old thread but there's one thing I cant grasp on this procedure. On reassembly..how do you get the voice coil centered? I have done LE14H-1's no problem..but I dont see where any adjustment is on the 044Ti's. I have eight of these to do eventually.

the dia is mounted in the "plinth" and not moveable. the plinth has 4 holes through it that go into threaded holes in the mag. they have to be aligned for the bolts to go back in ... thus aligning the vc.

[LHorn]

the dia is mounted in the "plinth" and not moveable. the plinth has 4 holes through it that go into threaded holes in the mag. they have to be aligned for the bolts to go back in ... thus aligning the vc.

I see...so the tapered screw heads are actually doing the centering. That is the part I couldn't grasp knowing there is always some play with anything that a screw or bolt goes through. I would have thought pressed in guide pins would be in order for these.

Thanks for clearing that up SEAWOLF!

[SEAWOLF97]

I see...so the tapered screw heads are actually doing the centering. That is the part I couldn't grasp knowing there is always some play with anything that a screw or bolt goes through. I would have thought pressed in guide pins would be in order for these.

Thanks for clearing that up SEAWOLF!

I think you got it, despite my description ... I can see from the black marker scribble that I must have put a mark to reassemble with correct orientation, since AFAIR, it can go either way.

the hardest part is just getting the glue/tape to release, and it immediately re-tacks if the surfaces contact.

It's been a couple of years, but I THINK that when the dome was reshaped and the foam plug inserted, that I spaced the plinth about a 1/4 inch above the mag with pencils or something., inserted the bolts and screwed down , maybe a half turn to get them started, then slowly removed the pencils and the plinth lowered exactly where it should be , following the bolts as guides.

[LHorn]

After looking at that pic again...I'm not sure I got it yet. The tapered head of the screws cant reach that far down to center the plinth can it...it will only center the top plate?

So lets say there is no glue on anything and you set the wooden plinth/diaphragm down on the magnet...then screw in the 4 screws. Wont the plinth be able to move slightly since there would be a little play between the screws and the plinth holes? The screws would have to physically touch the plinth for no movement to occur...acting like a guide pin.

With such a close tolerance the voice coil has in the gap its strange that wood was even used given it can change or flex in different environments. Maybe not so much after clamped down but still.

[DavidF]

You can apply a test tone (1,000 Hz with 10mF capacitor in series) to the tweeter. As you lower the diaphragm assembly down near the pole the coil will start to pick up the signal even if it is not yet in the gap. You will hear a clear tone as long as there is no contact with the gap.

[LHorn]

I see...I figured there had to be some way to align the vc since it cant be shimmed. To be sure I have this right...I do have a 10k uF cap..same thing right?

Thanks DavidF.

[DavidF]

I see...I figured there had to be some way to align the vc since it cant be shimmed. To be sure I have this right...I do have a 10k uF cap..same thing right?

Thanks DavidF.

Typo, yes. 10uF with a low signal level just long enough to set the piece.