Need help in identifying pair of JBL Alnico 2402 Diaphragms

[Mr Wizard]

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Are they made by JBL or are they aftermarket diaphragms?

Thanks,


64943

[ivica]

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Are they made by JBL or are they aftermarket diaphragms?

Thanks,





Hi Mr Wizard,

Using RED dot, or either LARGE BLACK dot to mark "+" polarity connection is not what JBL has done on their diaphragms. Usually dot is small black.

regards
ivica

[1audiohack]

I would wager the yellow one on the left is genuine JBL. The other I am less than sure.

They both look like they have some deformation though and that can be problematic.

Did you hear them? If so did they seem OK?

Barry.

[Mr Wizard]

I would wager the yellow one on the left is genuine JBL. The other I am less than sure.

They both look like they have some deformation though and that can be problematic.

Did you hear them? If so did they seem OK?

Barry. No, I did not hear them.
I also noticed deformation.
One other thing that is in question, they read 8.0 and 8.2 ohms.
Is this a normal ohms reading for 2402 diaphragms ?

[Mr Wizard]

Hi Mr Wizard,

Using RED dot, or either LARGE BLACK dot to mark "+" polarity connection is not what JBL has done on their diaphragms. Usually dot is small black.

regards
ivicaIs this a uniform practice for genuine JBL diaphragms?

[Mr Wizard]

According to this 2402H Technical manual (http://jblproservice.com/pdf/Discrete%20Sales%20Models/2402H.pdf) under System Components
DC resistance is suppose to be 6.25 ohm + or - plus or minus 8%

So I would say they both are not genuine JBL diaphragms.

What is the value of a pair of JBL 2402 Alnico tweeters with aftermarket diaphragms?

Thanks,

[ivica]

According to this 2402H Technical manual (http://jblproservice.com/pdf/Discrete%20Sales%20Models/2402H.pdf) under System Components
DC resistance is suppose to be 6.25 ohm + or - plus or minus 8%

So I would say they both are not genuine JBL diaphragms.

What is the value of a pair of JBL 2402 Alnico tweeters with aftermarket diaphragms?

Thanks,

Hi Mr Wizard,

It seems to me that these are AlNiCo "motor" type ( models: 2402A, or 075), with no oxides on the top-plate ( but better would be seen whet the diaphragms would be removed).
The problem with AlNiCo motor can be its 'magnetic strength", as I have seen some of them that had reduced magnetic strength, and the results were lower efficiency and lower frequency response. Such can happen when using AF diaphragm, in order to produce desired sound level.
Such problem I have not seen on ferrous-magnet motor type (models: 2402H)
Unfortunately the measurements of the magnetic strength can be done by special equipment or may be by comparing the efficiency to the known good one piece (using the same ORIGINAL D8R075 diaphragms).
I would not expect the price for the 2402A 'motor" to be over 100 $/per piece. But the price for the D8R075 can be over 150$/per piece.

Regards
Ivica

[Mr Wizard]

It seems to me that these are AlNiCo "motor" type ( models: 2402A, or 075), with no oxides on the top-plate.
Using AF diaphragm,
Regards
Ivica How many different models of the Bullet type tweeter did JBL produce?
I know of the:
075
2402
2402H

Is there also a 2402A?
What do you mean oxides on the top-plate?
Does AF stand for Aftermarket?
Is there a DC resistance ohms range, for the genuine JBL diaphragms, that you have encountered?

Please excuse my ignorance.

Thanks,

[ivica]

How many different models of the Bullet type tweeter did JBL produce?
I know of the:
075j
2402
2402H

Is there also a 2402A?
What do you mean oxides on the top-plate?
Does AF stand for Aftermarket?
Is there a DC resistance ohms range, for the genuine JBL diaphragms, that you have encountered?

Please excuse my ignorance.

Thanks,

Hi Mr,
as I know, 075 = 2402 Alnico, while 2402H is ferromagnet,
AF aftermarket
I have no info about DC resistance of 2402 either 075.

regards
ivica

[martin2395]

The left one looks original to me but overall they look tired.

Also, my 2405H's with genuine phrams both measured around 6,8 ohms ;)