"044" & "Others"?

If I have already asked this and forgotten, please forgive :)

Is there an acceptable/determined to be so, solution for renewing the foam damping behind the diaphragm domes (short of buying a new diaphragm assembly)?

I have no ability to experiment and sweep check so I was hoping someone could make a specific recommendation for a material I could simply procure, cut and install. Size or weight would be extremely helpful too.

"044"s are my main interest, but I have some aging "035Ti"s as well.

I'd like to have the the ability/option to refresh, if needed, when I have them out of their holes while doing other work

Thanks to all :bouncy:

Thomas

Quote:

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Originally Posted by grumpy

The question is not a new one:

http://www.audioheritage.org/vbullet...light=044+foam

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Hi grumpy and thanks.

Yeah, I've seen it discussed before, I was mainly interested in if someone had identified a good, specific replacement, like "Acme Super DeLuxe Window Foam" available at a dime store near you. In other words, is there a known quantity?

Not being a smart ass, but I can't touch the sample in the photos to get an idea as to how to guess what to try. I would feel better as well knowing that another member had verified good results.

Thanks again,
Thomas

I understand, but short of an actual kit, it's guesswork.

fine, soft, open-cell foam is what I've taken out, and put in
(actual kits).

something like this, perhaps:

http://www.mcmaster.com/#polyurethan...-cubes/=6tufrz

Quote:

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Originally Posted by grumpy

I understand, but short of an actual kit, it's guesswork.

fine, soft, open-cell foam is what I've taken out, and put in
(actual kits).

something like this, perhaps:

http://www.mcmaster.com/#polyurethan...-cubes/=6tufrz

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Thanks again.

Looks good on paper. What did you get, the 1" cubes?

I've emailed them to see if they have a minimum order policy.

Thomas

No, I used actual JBL kits... didn't mean to imply I had used that particular
material. Having had the real-deal to squish between my fingers just gives me
an idea of what might be a suitable replacement. The 044's I've repaired were
all fixed for a reason (open voice coils), so I don't have a subjective, or measured
before/after to judge what difference an old/squished/deteriorated foam piece
vs. a new one (that did noticeably require a small amount of compression under
the dome) makes... or a how foam with -slightly- different density or compressibility
might change things (just guessing not a lot).

McMaster-Carr is just a vendor that carries an insane amount of hardware
and was what came to mind... a search brought up the material I referenced...
-appeared- by description to be reasonably close.

Quote:

---

Originally Posted by grumpy

No, I used actual JBL kits... didn't mean to imply I had used that particular
material. Having had the real-deal to squish between my fingers just gives me
an idea of what might be a suitable replacement. The 044's I've repaired were
all fixed for a reason (open voice coils), so I don't have a subjective, or measured
before/after to judge what difference an old/squished/deteriorated foam piece
vs. a new one (that did noticeably require a small amount of compression under
the dome) makes... or a how foam with -slightly- different density or compressibility
might change things (just guessing not a lot).

McMaster-Carr is just a vendor that carries an insane amount of hardware
and was what came to mind... a search brought up the material I referenced...
-appeared- by description to be reasonably close.

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Understood.
They have no minimum so that's good.

So, as it stands now, maybe the softest, open cell "Super Deluxe" I can find locally might just work as well.

Large enough piece (height) to just lightly "kiss" the back of the dome?
Same diameter as the pole piece?

Thank you again,
Thomas

foam just cleared vc former on the inside dia.

height of foam in stock kit was surprising...
sufficient to touch the dome interior at its highest point
away from the pole piece, requiring some compression.

Note that -all- of the old foam pieces I've extracted had
(over time) permanently conformed to the dome shape,
having started with a flat top.

Quote:

---

Originally Posted by grumpy

The 044's I've repaired were all fixed for a reason (open voice coils), so I don't have a subjective, or measured before/after to judge what difference an old/squished/deteriorated foam piece vs. a new one (that did noticeably require a small amount of compression under the dome) makes... or a how foam with -slightly- different density or compressibility might change things (just guessing not a lot).

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Yeah, I know it's an old thread but I've had one of the 044ti in my "new" 240ti twice already since when I got them one was dead. Amazingly after pulling the diaphragm off the magnet assembly using spudgers and a heat gun . . . it measured and worked properly—for a few days. Did it again and no joy. So I have two used ones coming from California and just received four diaphragms from AliExpress today. Were you able to fix the open VC in the ones you took apart?

I posted this a couple of places but I'll do it again here in the hopes it helps someone going forward:

https://live.staticflickr.com/65535/...ccbbea41_k.jpg

"repaired", in my case, meant installing new D8R044* kits. So, the voicecoils were replaced as well (not particularly helpful).

The interesting thing with yours is that it came back... so there's a real possibility that there's a repairable open (or short? haven't read the full story)... perhaps the lead outs from the VC itself or an early sharp bend where they meet where an intermittent connection is stressed (pulled open) after a time.
Is it all OK (steady DC resistance) with the diaphragm kit removed?, which could point to the terminations (or insulation issues). A not so happy finding would be a problem in the voicecoil winding itself, not close to the "entry/exit" leads.

Assuming you are able to locate the issue, the very fine wire with lacquered insulation would need to be carefully scraped (at the ends to be rejoined) prior to attempting to do any soldering... then making sure the fixed area doesn't short on anything.

Good luck with the new diaphragms, also!

Quote:

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Originally Posted by grumpy

"repaired", in my case, meant installing new D8R044* kits. So, the voicecoils were replaced as well (not particularly helpful).

The interesting thing with yours is that it came back... so there's a real possibility that there's a repairable open (or short? haven't read the full story)... perhaps the lead outs from the VC itself or an early sharp bend where they meet where an intermittent connection is stressed (pulled open) after a time.
Is it all OK (steady DC resistance) with the diaphragm kit removed?, which could point to the terminations (or insulation issues). A not so happy finding would be a problem in the voicecoil winding itself, not close to the "entry/exit" leads.

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Thanks for continuing the conversation.
It would appear to me that the heat I used to remove the diaphragm is what caused it to work again. When it stopped functioning, I removed it again still on the board and heated it up again without removing it, concentrating the heat around the dome from the top. Once again it worked for a short time. There is no open circuit from Faston connectors to where the wire becomes part of the VC. I used tiny pins to test the circuit each time, which leads me to believe it is an open circuit somewhere in the voice coil. I'll be a bit more invasive with it once I have a working replacement but, even under close examination with a magnifying glass, I couldn't find a visual indication of an open circuit. It is doubtful I'd be able to effect a repair in that area, anyway. Hence the replacement. At that point I really have nothing to lose with the Chinese diaphragms as an experiment. I think I have less than $20 invested in the parts from AliExpress. Pictures on those and their DCR maybe later today.