View Full Version : "044"s

08-16-2009, 08:15 PM
I removed the screen today from one of mine to straighten out a small dent in the screen.
I observed that the dome is not concentric with the round opening in the frame/lens faceplate.
This tweeter seems to be working fine, but I have only been listening casually (waking them up) as this is in my newly acquired pair of L112s.
I'm not going to start looking for a problem that isn't here, but just in case it comes to it, I was wondering and cannot find:
Is the diaphragm in the 044 aligned with pins? (reasonably fool proof)
Does anyone else have a working 044 in which the diaphragm does not look concentric in it's hole when viewed straight on?
I have 3 others and they all appear concentric (but I haven't pulled off their screens just for this).
There is no evidence of tampering, damage or service work.
Any insight would be greatly appreciated.

08-16-2009, 08:38 PM
The diaphragm and it's board are positioned and held in place only by the 4 screws that you see. If it's working well, leave it alone.

08-16-2009, 08:51 PM
The diaphragm and it's board are positioned and held in place only by the 4 screws that you see. If it's working well, leave it alone.

I would tend to agree. But at the same time I have wondered if replacing the foam damping plugs behind the domes is worth the effort, in and off itself? Do the little plugs retain any of their dampening qualities after 30 years? I know they usually disintegrate when the diaphragms are removed for service. EV used a little tuft of fiberglass in some of theirs. Makes one wonder what would work just as well that wouldn't disintegrate over time; a project unto it's self.

To any and all: the foam plugs worth servicing as restoration/maintenance for the optimum performance of other wise sound intact examples?


08-16-2009, 09:36 PM
If you could get the foam plugs (and spare diaphragms) it might be worth it.
I thought they were NLA. I've taken apart several 044's and replaced a dome
with an NIB JBL kit... The foam had adhesive on one side and was in contact
with the dome on the other. None had completely disintegrated, although
all had taken the form of the dome (not sure if they were still touching).
The new kit's foam was necessarily compressed by the installed dome
(taller than the installed dome height).

There is also adhesive (on the units I disassembled, and on the kit) that
stabilized the location of the installed diaphragm. All of the screws come
off easily enough, but my experience was that the adhesive was fairly
aggressive and required patience and finesse to keep from ruining the
voice coil, dome, or the fiber substrate itself... others seem to have had
less trouble with this.

Short version? I'd personally leave it alone if it sounds OK. If you can
loosen the front screws and center the assembly behind the fascia a bit,
it shouldn't hurt anything.

08-17-2009, 06:02 AM
I've had several apart and the foam was intact in each.
The relationship between the dome and the outer frame is not important as long as the voice coil is centered. I'd assume this one is fine.

The diaphragm assembly is supposed to be glued to the magnet and shouldn't move around when the screws are loosened. But I'd assume that Murphy is on duty and leave it alone.