2405 with 2402 diaphragm.

[Doc Mark]

Greetings, Friends,

Probably 20 years ago, I bought a spare 2405 from a friend of mine, for $90. When I picked it up, I ran a signal through it, at very low volume, just to make sure it wasn't dead. I noted that the back JBL 2405 plate had gone missing, and that someone had used a magic marker to write a few things on tape on the back of the magnet housing. Since then, I sort of forgot about that, until the other day, when checking to make sure it was ready for the upcoming 4-way system. It appears that in July of 1991, someone changed out the diaphragm on this 2405 with a new one for a 2402/075. After doing a bit of research here on the forum, I'm confused a bit. Some strong information here states that the JBL part number for both the 2405 and the 2402, is the same number. But, others have suggested that this may not work. I'm leaning towards what was in the Transducer information here on LH, and somewhat discounting those who expressed doubts about how this would work. I'm I on the right track? The note on the back of my old 2405 reads: "New Dia. 2402/075, 7/91". Back in '91, was the part number the same for both the 2405 and 2402 diaphragms , as it appears to be now?

I guess the proof will somewhat be in the pudding, when I finally get everything hooked up and running. But, I'd really like to know if what I've read about the part numbers for both 'phragms being the same. Thanks for any comments and info you can send my way. Take care, and God Bless!

Every Good Wish,
Doc

[gibber]

Dear Doc,

the fram for the ring radiator is wider (more area) both inside and outside of the coil touching it.
It will fit your magnet no problem there. While sound is not too different, it won't be the same as a 2405 fram.

You mention only one. If this is for a center or a mono application, don't worry about it.

Ralph

[JeffW]

I think you are misunderstanding the part numbers, Doc. In the long post comparing the different diaphragms, it is mentioned that the diaphragms for ring radiators share the same voice coil and DCR, but the diaphragm assemblies are different with different part numbers.

For a 2405, you want a D16R2405. The part for a 2402 is D8R075 The 2404 uses the D16R2405, and the 2404H-1 uses the D8R075.

http://www.audioheritage.org/vbullet...-2404-077-2405

[Doc Mark]

HI, gibber, and JeffW,

Thank you, Gentlemen, for your comments. Looks like I'll eventually have to seek out a NOS JBL2405 diaphragm, as I'm not keen on using after market stuff, unless there is no other option. Thanks, again, and much appreciated. Jeff, those 2445 diaphragms you so kindly sent my way will finally be getting tested, when this system if fully operational. Thanks, for all your help on numerous fronts, my friend!! Take care, and God Bless!

Every Good Wish,
Doc

[JeffW]

The D16R2405 are still in production, but there have been teething pains that may or may not be rectified by now. That, and they are pretty dearly priced.

[1audiohack]

The last half a dozen that I have bought have been just like the ones from the good old days.

On the good news front, there has slowly been more and more old pro cone kits on the JBL available list. No E series yet though.

Barry.

[JeffW]

The last half a dozen that I have bought have been just like the ones from the good old days.



Barry.

That's good to hear!