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clubman
03-14-2010, 02:56 PM
Just had a diaphram fail in my 175 driver. It was original with the red wax seals. When I opened the driver I found the diaphram to be perfect but measured open with a meter. With a closer look I found the diaphram torn at the base of the dome. It was torn where the positive lead wire went across the back of the diaphram. In turn the lead wire was torn too. Is this just from old age or what? Anyone see this happen before?

edgewound
03-14-2010, 10:11 PM
Typical metal fatigue in an ancient diaphragm that has seen lots of action.

Wagner
03-15-2010, 02:44 PM
Typical metal fatigue in an ancient diaphragm that has seen lots of action.


Are O.E. diaphragms, or better, still available for the 175?

Thank you,
Thomas

edgewound
03-15-2010, 08:58 PM
Yes...OEM would be either aluminum 2421or titanium 2425.

2421 is about twice the price of 2425.

Wagner
03-16-2010, 06:10 AM
Yes...OEM would be either aluminum 2421or titanium 2425.

2421 is about twice the price of 2425.


Odd, the titanium cheaper than aluminum?
Which do you get the best feedback from and or prefer yourself?

My old drivers seem OK for now but I should probably squirrel an O.E. pair away while they're still available.

Thank you,
Thomas

toddalin
03-16-2010, 09:21 AM
Yes...OEM would be either aluminum 2421or titanium 2425.

2421 is about twice the price of 2425.


Proper diaphram is the 2410 and still listed at OCS.
http://www.speakerrepair.com/mm5/merchant.mvc?Screen=PROD&Store_Code=genem&Product_Code=10-251&Category_Code=l_jbl_dias

edgewound
03-16-2010, 07:36 PM
Proper diaphram is the 2410 and still listed at OCS.
http://www.speakerrepair.com/mm5/merchant.mvc?Screen=PROD&Store_Code=genem&Product_Code=10-251&Category_Code=l_jbl_dias

Yes...and the 2410, 2421 and 2425, 2470(phenolic) diaphragms are all interchangeable. 2410/LE175 has the tangential compliance.

2421 and 2425 have the diamond pattern compliance.

For longest lasting durability in a metal dome, the titanium unit gets the nod. A coat of aquaplas will tame the resonances of the 2 mil dome.

speakerex
03-17-2010, 11:08 AM
The JBL 175 diaphragm has not been available for quite a long time. The diaphragm suggested by JBL for use in this driver is the D16R2410. We have used this many times in this driver and have never had any complaints. We are happy to provide them for anyone who needs them. cathy@speakerex.com

Wagner
03-18-2010, 08:18 AM
The JBL 175 diaphragm has not been available for quite a long time. The diaphragm suggested by JBL for use in this driver is the D16R2410. We have used this many times in this driver and have never had any complaints. We are happy to provide them for anyone who needs them. cathy@speakerex.com


It would be wonderful if you would happily sample me a couple :bouncy:

Regards and thank you in advance,

Thomas

speakerex
03-18-2010, 09:12 AM
You can order from our website www.speakerex.com (http://www.speakerex.com) or call and place an order. 800-849-6972

Wagner
03-18-2010, 04:34 PM
You can order from our website www.speakerex.com (http://www.speakerex.com) or call and place an order. 800-849-6972


What a generous gesture, thank you!
Do I reference "Cathy sent me" to let them know this is a complementary sample deal?

Thanks again :bouncy:

Thomas

speakerex
03-19-2010, 08:43 AM
you're so cute. go for it. never hurts to try. thanks for being so much fun!! you remind my why I enjoy this work. lately everything has become toooo serious. I keep reminding myself this isn't neurosurgery

Wagner
03-19-2010, 10:14 AM
you're so cute. go for it. never hurts to try. thanks for being so much fun!! you remind my why I enjoy this work. lately everything has become toooo serious. I keep reminding myself this isn't neurosurgery


So does this mean I'm getting my sample diaphragms, or not?

Thomas

speakerex
03-19-2010, 10:26 AM
sure we can send you a sample. the handling costs $199.00 and the shipping should be about $10-12.00 for anywhere in the continental us

clubman
03-19-2010, 11:22 AM
Just replaced with a 2425 and called it a day......

Beowulf57
03-19-2010, 12:25 PM
If the D16R2410 can be used in an LE85/2420, how does it differ from the D16R2420? I know the LE85 has a more massive magnet assembly than the LE175 (to extend bandwidth), but are there any differences in the diaphragms?

toddalin
03-19-2010, 12:38 PM
If the D16R2410 can be used in an LE85/2420, how does it differ from the D16R2420? I know the LE85 has a more massive magnet assembly than the LE175 (to extend bandwidth), but are there any differences in the diaphragms?

This has been asked before, but never answered. :banghead:

Beowulf57
03-20-2010, 06:09 AM
This has been asked before, but never answered. :banghead:

Okay...I'm with you...:banghead::banghead:

SMKSoundPro
03-20-2010, 09:54 PM
Well, I have two OEM 2410 phragms in my 2410's here on my workshop shelves that I have never plugged in.

I have the LE85's out of the L200b's just hanging out. I also have some 2421's with OEM phragms. Why don;t we figure this out?
Scotty.

Beowulf57
03-21-2010, 07:37 AM
Well, I have two OEM 2410 phragms in my 2410's here on my workshop shelves that I have never plugged in.

I have the LE85's out of the L200b's just hanging out. I also have some 2421's with OEM phragms. Why don;t we figure this out?
Scotty.

Excellent! As a start, are the 2410 and 2420 diaphragms 8 ohm or 16 ohm? Similar DCR's? Can you visually inspect the diaphragms for differences? Ideally, one would run a sweep on the two diaphragms under comparison installed in the same driver...however that's a fair amount of work and requires swapping diaphragms...if you are equipped and up for it!?:applaud:

toddalin
03-21-2010, 10:02 AM
At one point, somewhere, probably on this forum, I read that supposedly the 175 diaphram was too light for use in the LE-85 motor assembly.

Seems to me that if it were lighter than the LE-85 diaphram, it should have a more extended high end than in the LE-175 motor and as long as these are kept in the home at tolerable levels, this really shouldn't be a problem.

Wagner
03-21-2010, 11:15 AM
So I am still wondering:
Is the "2410" or the "2421" the modern direct exact replacement for what came in the 175?

I understand that there are several diaphragms that will fit; I'm wondering which one is the closest to an exact match?

If running these with a stock, VERY Vintage N1200, would the Titanium options offer any advantages over Aluminum types other than durability and price, subjective sonic qualities aside?

Mine happen to be 16 Ohm models, will switching to 8 Ohm make them any more flexible beyond network compatibility with specific networks?

Thomas

Mr. Widget
03-21-2010, 11:50 AM
So I am still wondering:
Is the "2410" or the "2421" the modern direct exact replacement for what came in the 175?Based on my knowledge of other JBL parts nomenclature, I would assume the D16R2410 is the exact replacement for the 175. At some point during the 70s all of the consumer drivers' replacement diaphragms were given the pro model numbers. Since JBL does not produce identical parts with different part numbers, (to my knowledge) the D16R2410 and the D16R2420 diaphragms while outwardly identical must be different... perhaps the mass as Todd suggests.

The D16R2421 diaphragm is certainly not identical as it has the newer diamond pattern surround design. as do all of the titanium models.

Widget

Beowulf57
03-21-2010, 01:39 PM
It does make sense that differing part numbers imply different parts...but it is still unclear what that difference may be? Both the LE175 and the LE85 are rated at the same continuous power of 30 watts. Both were originally rated from 500Hz, the only difference being the top end: LE175 to 15KHz, LE85 to 20KHz. This was due to the larger magnetic structure in the LE85 which increased the magnetic flux density from 16,000 to 19,000 gauss. Given that most of the power is in the lower region of the bandwidth, both units have identical power ratings and identical sensitivity above 1KHz (59dB at specified input), I'm not sure why the D16R2410 diaphragm would be lighter?

Mr. Widget
03-21-2010, 01:56 PM
I'm not sure why the D16R2410 diaphragm would be lighter?I'm not sure why it would even exist, but the fact that it does exist makes me believe there is likely a difference. If it was identical to the older D16R2420 diaphragm, then why wouldn't it be listed as a replacement option for LE85s? Currently the "recommended" replacement for the LE85 is the D16R2421.


Widget

toddalin
03-22-2010, 10:19 AM
I'm not sure why it would even exist, but the fact that it does exist makes me believe there is likely a difference. If it was identical to the older D16R2420 diaphragm, then why wouldn't it be listed as a replacement option for LE85s? Currently the "recommended" replacement for the LE85 is the D16R2421.


Widget


A similar situation arises with the 2405/077. While functionally equivalent, they do/did list separate diaphrams. As we know the 077 diaphrams had the blue rings while the 2405s had the gold rings. On the Behringer 61-band RTA, my 077's and 2405's show slightly different spectra.

Beowulf57
03-27-2010, 05:31 AM
A similar situation arises with the 2405/077. While functionally equivalent, they do/did list separate diaphrams. As we know the 077 diaphrams had the blue rings while the 2405s had the gold rings. On the Behringer 61-band RTA, my 077's and 2405's show slightly different spectra.

Is this a large enough sample to rule out simple unit to unit variation? As in could one observe this amount of difference between two 077's or two 2405's?

toddalin
03-27-2010, 09:46 AM
Is this a large enough sample to rule out simple unit to unit variation? As in could one observe this amount of difference between two 077's or two 2405's?


Small sample, but the two patterns were pretty much distinguishable. Most of the difference was below the typical crossover frequency, but is evidenced by using pink noise and a simple cap of about 4 mfd.

Mr. Widget
03-27-2010, 09:52 AM
Is this a large enough sample to rule out simple unit to unit variation? As in could one observe this amount of difference between two 077's or two 2405's?No, the sample size wouldn't be conclusive, and a Behringer test is hardly conclusive. That said, there is a thread where the different ring radiator diaphragms were physically compared and the diameters of the inner aluminum rings are measurably different. The diaphragms are different, each one specifically designed for it's application.


Widget

herki the cat
03-27-2010, 03:56 PM
Yes...and the 2410, 2421 and 2425, 2470(phenolic) diaphragms are all interchangeable. 2410/LE175 has the tangential compliance.

2421 and 2425 have the diamond pattern compliance.
For longest lasting durability in a metal dome, the titanium unit gets the nod. A coat of aquaplas will tame the resonances of the 2 mil dome.

Hello edgewound, i have a pair of 2425's purchased, day one, which seemed then like a good idea for extended life & durabilty in my LC9-A Horns.

I have four 2470's & spare diaphragms with excellent fs damping & very smooth artifact-free response. The 2470 motor mass contributes significantly here.

Can you tell me what to expect from the 2425 equipped with 2470 diaphragms.

cheers herki the cat

edgewound
03-27-2010, 06:34 PM
Hello edgewound, i have a pair of 2425's purchased, day one, which seemed then like a good idea for extended life & durabilty in my LC9-A Horns.

I have four 2470's & spare diaphragms of excellent fs damping & very smooth, artifact-free response afforded to an important level by the 2470 motor mass.

Can you tell me what to expect from the 2425 equipped with 2470 diaphragms.

cheers herki the cat

It would be the same specs as the 2470. The specs of the driver follows the diaphragm that is installed. In theory, anyway...Variations in motor strengths will alter the response.