Playing with a 2426

[Guido]

If I would drop a 2421 dia into a 2426 and keep away the alnico ferrite debate, would it result in a 2420like driver?
Or are there significant changes in the phase plug?

Ok Ok, I could just try it but what is the opinion about this?

[spkrman57]

I just bought a pair of JBL 2426J's and have been using Altec 802/806/807/808's for some time now. I also picked up a pair of 902's lately and trying to compare the difference. Hard to tell so far, they are different, just can't put my finger on it.

So when I get the 2426's mounted on horns, I will see how they compare to the Altec 802/806 drivers(alnico), and the 902(ferrite).

Still looking for different crossovers to try out. Currently using 3rd order w/HF compensation networks.


Let me know how it all comes out. I am curious!!!

Ron

[Mr. Widget]

Let me know how it all comes out. I am curious!!!

I am too. I would be interested in both subjective and if possible objective comparisons.

Widget

[Guido]

The 2426 drivers I bought w/o dia on ebay will arrive next week. I'll then equip them with brandnew 2421 dias and do a comparison to my 2420 that also have brandnew 2421 dias.

I just dont want to part my existing 2426. So we need to wait a bit.

[spkrman57]

Has anyone actually tried it out?
Ron

[Earl K]

Well I know first hand that a 2410 diaphragm fits nicely into the newer ferrite magnets .

I see no reason why the 2420 or 2421 wouldn't also fit into the newer ferrites. JBL hasn't changed the magnets gap sizes or mounting hole spreads / etc. .

Note : the 2410 ( le175) diaphragm installed into a 2420/1 or 2425/6/7 magnet isn't a JBL authorised combo . ( It's a slightly lighter diaphragm )

[Guido]

Argh!

This was hard work. After sticking 20 minutes INSIDE my 4343 and couldn't get out this 2420 I decided to open the front baffle. I tell ya...

OK, here are the results:

Impedance
Blue = 2426 with fresh D8R2425 on 2344
Red = 2426 with fresh D16R2421 on 2344
Orange = 2420 with fresh D16R2421 on 2344

[Guido]

Response:

Blue = 2426 with fresh D8R2425 on 2344, Clear extended HF-Response
Red = 2426 with fresh D16R2421 on 2344

Pure drivers

[Guido]

Response with 3135 network

Violet = 2426 with fresh D8R2425 on 2344, extended HF-Response
Green = 2426 with fresh D16R2421 on 2344
Orange = 2420 with fresh D16R2421 on 2344

[Zilch]

I'm finding old LE85's (16 Ohms, though they say 8) play fine on N3134, have more extended HF response than 2426H or J, and sound better (smoother).

Thinkin' about springin' for a pair of D8R2421 aluminum diaphragms to put in a pair here....

[I think that's the number, the original 4430 diaphragm....]

YIKES! $244 per each!

Why'd you get D16R2421's?

[Guido]

Why'd you get D16R2421's?

I use them in my 2420 for the 4343.

[Mr. Widget]

Could you make comparisons with no network ahead of the drivers? The impedance mismatch is most likely affecting your results. It would be interesting to see all of the drivers on the 2307 as well.

Your plots do show that the aluminum diaphragm has reduced that (nasty) peak at 4KHz....

Widget

[Guido]

Could you make comparisons with no network ahead of the drivers?

See Post #8

It would be interesting to see all of the drivers on the 2307 as well.

No chance! It's back into the 4343

Your plots do show that the aluminum diaphragm has reduced that (nasty) peak at 4KHz....

This peak is app. +3 or +4 dB so its inside the range I think

[Ian Mackenzie]

Just shunt a 20 ohn resister on the drivers where the impediance is 16 ohms

[Guido]

I'm finding old LE85's (16 Ohms, though they say 8) play fine on N3134, have more extended HF response than 2426H or J, and sound better (smoother).

I'll sure give my extra pair of 2426 with 2421 dias a try in my 4435 as soon as they are finished. The "smoother" sound many members refering to makes me curious
Maybe a nice (blind) A/B test with one side 2426/D8R2425 and 2426/D16R2421 at the other side?

The impedance missmatch could be eliminated by changing the parallel resistor in the 3134 network to 5.1 ohm (changing to 7.5 ohm in the 3135?). I discussed this with Giskard and it should not work 100% correct but it should work.