is this an orginal JBL 2426H driver ????

[MatthiasA]

Hello i rebuilt the S2600
now i mounted the driver on my horn!
my first impression wasn't very well..
is this an orginal JBL 2426h driver ?? or a unknown rebuilt?

[MatthiasA]

greetings matthias

[Earl K]

- Yes, that looks to be a JBL 2425 , the predecessor to the 2426 .

- Make sure it's the 8 ohm type by measuring the DC impedance ( DCR ) with a multimeter . DCR for the 8 ohm 2425H will be in the 3.2 to 4 ohm range . If it is twice that number then you have a 16 ohm 2425J . If you have a 2425J , the impedance mismatch with your present crossover values will throw the sound of the hipass all out of whack .


:cheers:

[MatthiasA]

its the 8 ohm version
ok but is that the right driver for the S2600 ?

habe you the spec sheet of both drivers? 2426h and 2425h?

anyone from belgium sold me this driver as the 2426h!!!:baby: :biting: :baby: :biting: :banghead:

[Earl K]

Hi Matthias,

- Well, it's good the drivers are the correct impedance. That will save you from having to rebuild your crossovers.

- The performance of the 2425 and the 2426 is virtually identical .

- The changes that JBL introduced to the 2426 were just about all cosmetic. The 2426 has a removable, threaded, adapter plate / while the 2425 doesn't.

- Here's a link to the 2426 pdf among some other JBL drivers. (http://jblpro.com/pages/components/cmp_drvs.htm#2426HJ)

- Click this link to download the 2425 product sheet. (http://jblpro.com/pub/obsolete/2425hj.pdf)

- In the meantime, Bernard is correct, you must listen to the woofer in the box along with the horn before any meaningful subjective evaluations can be made.

- I recommend against anyone opening up any compression driver if the person doing the "opening" doesn't know how to clean the gap of derbis & then recenter the diaphragm during reassembly . For instance ; It's quite easy to ruin a diaphragm by keeping those leads attached to the backcap and then lifting it out . The reason ? Those thick wires act like a third pair of hands, generally misguiding and hindering proper recentering & replacement of the coil into the gap.

:)

[MatthiasA]

thank you very much ! now its all ok !

ive testet the woofer + the horn !
its the same volume!

greetings matthias

[ralphs99]

That's good advice Earl.

Do you have a procedure for cleaning the gap and re-centering the voice coil when a diapragm is removed? The question has probably been answered before so maybe someone can send a link.

Cheers, Ralph.

[Earl K]

Gap Cleaning & Diaphragm Centering : The question has probably been answered before so maybe someone can send a link.

Here's a pretty decent link on the subject . (http://audioheritage.csdco.com/vbulletin/showthread.php?t=700&highlight=Diaphragm+Centering)

Ralph, did you ever purchase the 275nd diaphragms that you inquired about some time ago ?

:cheers:

[ralphs99]

Thanks for the link Earl! It's exactly what I needed to know.

I made some enquiries here on the forum but couldn't get any inside deals on the 275nd's. I then got a price from JBL in Australia but the price was way too high. Finally I got talking to Mike at Vintage Audio Sales and we worked out a deal for some used 2426's he has available. I figured that even if I didn't like them better than the original diaphragms in my 2420's, I could always sell them again. So now I'm keenly awaiting their arrival in the post. They should be here anytime now! Then I hope to have a solution to the uneven midrange response problems I have been experiencing. I'll keep you posted when I get some results.

Cheers, Ralph.:cheers:

[MatthiasA]

Hello! ive a question

ive opened the driver and took the diaphragma out
i took it in the hole back and close the driver - its sounds good
is this the right methode ?
i know i ve to work exactly but what can i do wrong by replacing?

greetings

[Earl K]

ive opened the driver and took the diaphragma out
i took it in the hole back and close the driver - its sounds good
is this the right methode ?

- No, it was not the right method .

- To find out about the correct installation procedures, read the posts from the thread that I posted a link to .

- The fact that it sounds good is somewhat beside the point.

- You just got lucky .


i know i ve to work exactly but what can i do wrong by replacing?

- The tolerances are extremely tight between the coil and the metal forming the gap. They can't touch . If the coil even just barely contacts the surrounding metal / the frequency repsonse curve is thrown off along with a substantial increase in distortion products .


:blink:

[MatthiasA]

ok i checked this ! its all ok !

[Guido]

i know i ve to work exactly but what can i do wrong by replacing?
greetings

Matthias!

You are crazy remove the dia without a clue!

Next time be careful with the screwdriver. If this gets into the magnetic field you need a new dia. 150 Euro.....

[MatthiasA]

Next time be careful with the screwdriver. If this gets into the magnetic field you need a new dia. 150 Euro.....

into the magnetic field?
you mean the dia?

if this gets into the dia? :blink: then i need a new dia.... ?

or how can i understand this?