044Ti questions/Help needed

[SEAWOLF97]

when I got the 18Ti's as donors for backups for the 250ti's , one of the 044ti's was dented.

My JBL friend who says he's fixed many Ti tweets and I pulled the driver ....to push out from inside , BUT can't get off the wood/masonite cover...can get a blade around underneath , staying clear of the dia , BUT it wont come off.

He suggested heat from a hair dryer , which I tried, but still no joy ...suggestions ?

and

once its out, dent removed....what glue shud be used to re-attach ?

[JeffW]

Can you try to pull it with a bit of low tack tape like masking tape?

[grumpy]

The current adhesive appeared to me to be akin to the double sided "Tape"
that really is just all adhesive (the backing gets thrown away)... at least in
the several 044's I've had apart. It can be scary-difficult to get the adhesive
to release, but it does ... it just seems to re-tack if you let it back down.

Slowly, and with more flat-bladed tools would seem like a good path to try
if you -really- want to separate the diaphragm from the magnet assy
(otherwise, good luck finding a new 044Ti replacement dia ... which would
have obviously been the preferred path).

I assume the Ti version also has the little foam cylinder inside, ... that may
or may not be reusable... one good reason to have a look :)

[grumpy]

... the voice coil. Definitely don't want to just slide a putty knife under the middle
and let 'er rip... 'cause it will.

[SEAWOLF97]

... the voice coil. Definitely don't want to just slide a putty knife under the middle
and let 'er rip... 'cause it will.

guess I'm always working on LF's and to me HF's either work or not , havnt had opportunity to open them and poke around..

is there a good cutaway view somewhere that will act as a road map ?

[grumpy]

the coil just drops down into the gap from the inside edge of the diamond pattern
(if looking from above). You've taken off the front section, but here's a cutaway pic:

47348

so... looking on-axis with the tweeter, there's a say 1.5-" diameter circle in the middle
that you don't want to slide a knife or tool into or you'll hit the voice coil former.

[SEAWOLF97]

I nominate Grumpy Dave as best Tech Responder of the day :applaud::applaud::applaud: thanx. !!

I wedged 6 screwdrivers under the plinth (for lack of better term) and about 2 hours later could hear it pop off....as you can see in the pix, its really only held on with some
double sided tape (the circle around the dia) ....pushed out pretty well , from behind the screen you cant tell. :D

the foam plug is crumbling ...left it in there until I can figure how to get a replacement (prolly need 4 of them ...2 for the spare 044Ti's and 2 in the 250ti's)

new glue prolly isnt needed as the screws go thru the "plinth" into the magnet and thats what really holds it .

its all back together and when the time permits, I'll check it out....

can the foam plugs be bought/sourced/substituted ??? :dont-know:

[grumpy]

There's a thread on the foam plugs somewhere here... Probably search on 044, foam, and grumpy to narrow the search... Seems like McMasters had something that would work...

Good to see you generally succeeded in your goal :)

[SEAWOLF97]

There's a thread on the foam plugs somewhere here... Probably search on 044, foam, and grumpy to narrow the search... Seems like McMasters had something that would work...

Good to see you generally succeeded in your goal :)

I ASSUME that the plugs are there to stop ringing ??? Mine are so far gone that its hard to tell what they were ....looks like it might have been a open cell foam ...McMasters has lots of product, just trying to find needed specs.

think I'm gonna open it again and make sure the gap is clear.

[grumpy]

http://www.audioheritage.org/vbulletin/showthread.php?28451-quot-044-quot-amp-quot-Others-quot&highlight=Foam+plug+mcmasters

[SEAWOLF97]

thanx G ...those links helped....dont know why my search didnt locate them.

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

anyway, found some fine pore open cell foam and am going to custom cut to fit. will make just smaller than the width,,,,,,, height ? shud it be touching the dome or not ?

sometimes I can see more in my pics than by eyeballing the project and noticed rotted foam in the gap ...will run some non-magnetic tool around in there (or maybe just blast it with 100 psi air) to make sure nothing impedes the cylinders movement.

[grumpy]

Dome doesn't need support, so yeah.

Factory foam piece actually took some -crushing- to get the 044 dome/fiberboard/assy
to sit flush against the magnet assy again... so there's definitely some damping going
on while the foam is still new-ish. I'd just err on the side of 'squishy' vs firm when
trying non-stock foam bits. pic in that thread shows what the stock foam cylinder
from a D8R044 (?) kit looked like (taller than I would have guessed, and it cleared
the side walls of the voice coil former). Definitely touching, in any case... seem to
recall it taking ~1/4" or more of 'squish'.

Someone could go nuts and do impulse, fr, and waterfall plots before/after/with/without
/etc... but I personally haven't the materials in hand.

[SEAWOLF97]

Dome doesn't need support, so yeah.

Factory foam piece actually took some -crushing- to get the 044 dome/fiberboard/assy
to sit flush against the magnet assy again... so there's definitely some damping going
on while the foam is still new-ish. I'd just err on the side of 'squishy' vs firm when
trying non-stock foam bits. pic in that thread shows what the stock foam cylinder
from a D8R044 (?) kit looked like (taller than I would have guessed, and it cleared
the side walls of the voice coil former). Definitely touching, in any case... seem to
recall it taking ~1/4" or more of 'squish'.

Someone could go nuts and do impulse, fr, and waterfall plots before/after/with/without
/etc... but I personally haven't the materials in hand.

Thanx for all the help Grumpy.....I reopened the driver today and hit the gap with 100 psi air...blew some junk out....found this foam in a packing box...its abt 10 years old, but its squishy and good resistance to tearing...cut a little plug abt 1/4" too high , the dome rested on it before re-screwing down...it did seem to fill out the dome shape a little, secured it with a drop of glue and it all went together very well. Shud prolly do the other 3 on some rainy day that I can't ride bike...:(

[roscoe1224]

we i understand im late to the party, but i just have to ask. How do you actually take an 044 apart? ive looked at mine to see if i could possibly remove the dents in the grille/mesh but im obviously missing something.

[SEAWOLF97]

we i understand im late to the party, but i just have to ask. How do you actually take an 044 apart? ive looked at mine to see if i could possibly remove the dents in the grille/mesh but im obviously missing something.

Oh, thats the easy part....there is just a little black "O ring" holding the grille/mesh in.

[roscoe1224]

the easy part huh? i looked at that thing for quite a while. i guess ive spent too much time with screws and bolts to think of tension attachment. thanks seawolf97

[rdgrimes]

If you're lucky, there's an o-ring in there.
Or maybe just parts of one. JBL still sells the o-rings, or did last year.

[briang]

Very cool thread, Seawolf!

[BMWCCA]

JBL still sells the o-rings, or did last year.

JBL/Crown/Harman were out of them as of last week when I purchased some other small stuff from them. Said it was still a good number though (#62664).

I ordered from Crown. The box label said Crown International. The packing list carried the Crown logo. The invoice with the Crown logo was mailed in a Harman International envelope from the same address (Elkhart, IN). The e-mail confirmation was from a Harman e-mail address and carried the Harman logo gif and no indication of any affiliation with Crown. :dont-know:

:(

[SEAWOLF97]

Very cool thread, Seawolf!

Brian...after your comment I re-read the whole thread and concluded that it is a rough approximation of how the forum should work

Guy #1 (Grumpy ) picked up the info somewhere or was bright enough to figure it out.

Guy #2 (me) gives it a try on his own, but get stymied..but asks for help ... #1 responds and together they figure it out...BUT #2 takes pics and notes a little sketchy details and posts his info

now you (or anyone with the same issue) can hopefully find this thread and feel more confident in tackling this task ...win/win/win :D



I ordered from Crown. The box label said Crown International. The packing list carried the Crown logo. The invoice with the Crown logo was mailed in a Harman International envelope from the same address (Elkhart, IN). The e-mail confirmation was from a Harman e-mail address and carried the Harman logo gif and no indication of any affiliation with Crown. :dont-know:

:(

cost ? min order ? shipping ?

[JuniorJBL]

I think I read somewhere here (I think it was 4313b) who worked on someone's 4" compression driver that had put the foam in with glue and it had created mold.

I think the foam plug by itself is all that is necessary. It is also the same foam for the 044 and I have done a few of these and all I did was set the foam in the center and then installed the Dia.
;)

[BMWCCA]

cost ? min order ? shipping ?
I was ordering "D" and "PS" series knobs and LEDs. Nothing big. About a $20 order. Shipping is $10 for all orders under $50. They're very nice folks and each time I order they take time to physically check inventory for me and then apologize for how long that took while I was on hold (never very long). Shipping is usually same day and arrives the next day via UPS.

I've gotten the o-rings before. I believe they were 36¢ each from JBL pro. Much more from JBL consumer. Could have been as much as a dollar. ;)

[roscoe1224]

so i got the dents out of my tweeter grills, thanks so much for the help y'all

[SEAWOLF97]

.
.
What would we do without all these dents anyway ??? :eek:

not obvious ...except for 3 hex heads , seems only way in....:dont-know:

[SEAWOLF97]

well , they ain't perfect (or even close) but they are a little more presentable ...put some silver paint on there , but the surface looked really uneven , went over with paint thinner and found the unevenness was caused by the original coating pealing. so with a rag and thinner I took off my paint & the original , happily it was still silver under everything.

[JBL 4645]

There's a thread on the foam plugs somewhere here... Probably search on 044, foam, and grumpy to narrow the search... Seems like McMasters had something that would work...

Good to see you generally succeeded in your goal :)

Grumpy

Can the foam decay as shown on the picture also change the way the tonal sound of tweeter if playing each tweeter side by side with same volume level while using pink noise would one not sound tonally different when in fact they should have the same timber balance?

[grumpy]

Hi Ash.

I would only offer my opinion that it would be difficult to tell the difference.
In other words, I wouldn't rip apart an 044Ti just to replace old foam unless
something -did- sound awry.

[JBL 4645]

Hi Ash.

I would only offer my opinion that it would be difficult to tell the difference.
In other words, I wouldn't rip apart an 044Ti just to replace old foam unless
something -did- sound awry.

Grumpy

Okay fair enough. Is it also possible that not all HF tweeter domes, that come out of factory are not built with equal tonal frequency timber balance?

I have to make a few EQ changes at the lower end of its frequency response capability 2KHz and while going up the scale. It can play 16KHz no sweat at all. I’m just curious as to why there is just a (tiny timber balance difference between the other two dome tweeters)?

I know what if I do a video with SPL placed near to it and then swap it around with the other tweeter domes, wired onto the same amp and see what you think?

http://i233.photobucket.com/albums/ee15/Evolution3417/MWTMNcolumbo5.jpg
Oh, there's just one other thing.

Is it not also possible they wound too much coil onto it, is that possible?

Also JBL didn’t make a MKII version or something, I just like to know why it has slightly higher rise around the lower portions of the high frequencies? all the crossovers are set equally and yes I have swapped the drivers around using the same amp and it doesn’t make a bit of difference.

It’s no big deal I can still cut around with the EQ.

[grumpy]

I think your best bet would be to find a spare drive unit, -then- poke around
the innards of the unit in question, or have it refurbished (always an option later).
Nothing like hands-on experience.

[JBL 4645]

I think your best bet would be to find a spare drive unit, -then- poke around
the innards of the unit in question, or have it refurbished (always an option later).
Nothing like hands-on experience.

:D
Well its funny you should bring that up! I have two knackered dome tweeters that gave up the ghost? Replacement driver whole part is around £30.00 pounds I think for C5. So a little peek won’t do much harm.

I was going to buy some replacement tweeters early around this, year. sigh, I’ll just get a two new dome tweeters for the other pair and then get a third at later time. Cheers, Grumpy I can’t be asked to open one of them up knowing the voice coil is fried. Guess that wouldn’t have happened if I had the DCX2496 a bit earlier with some audio limiting protection.

[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 :eek:

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) :bouncy:

[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.