n2400 crossover

[thymanst]

I have a question about the n2400 crossover - from what I've seen there is 16 ohm and a 8 ohm versions = from what I've read, the d130's are all 8 ohm... so is the 16 ohm n2400 really 16 ohm? - I'm trying to put together a pair of these to build d130/075 speakers this summer - I thought I had bought a pair in Canada, but the guy never shipped them and kept my money (Ross Mcknight AKA sam r i or fatonesam) paypal recovered a whole $2 from him - anyway if any leads on n2400 pls let me know (the d130's are 8ohm Signatures)

[BMWCCA]

I have a question about the n2400 crossover - from what I've seen there is 16 ohm and a 8 ohm versions = from what I've read, the d130's are all 8 ohm... so is the 16 ohm n2400 really 16 ohm?

My D130s are labeled 16-ohm and use N2400s. There's been much discussion here about the actual impedance of the D130. I believe Harvey may have said they were all the same, regardless of label. If you check the brochures in the library, up to around 1966 the D130 and the N2400 were rated 16-ohm. From about 1969-on both were rated 8-ohm. I assume they are the same, regardless of label. :dont-know

[Bumba]

Hello Baron,

I noticed the missing 1.4mH while searching online too . Will keep the JBL coils, order other parts and work on it. Thanks for your helps and suggestions.

bumba

[Beowulf57]

This should not be an issue...AFAIK JBL changed the nominal impedance ratings on drivers such as the D130 from 16 ohm to 8 ohm, however the actual impedance remained the same, unless you are talking about early models which where rated at 32 ohms. Here is the N2400 schematic if it may be of use to you: note that the test setup used an 8 ohm load for standardization.

[thymanst]

The best I can find right now is a one 8 ohm and one 16 ohm crossover - It look like there are some inexpensive JBL crossover with L-pads (crossed at 2.5 khz) that I could buy to hold me over until originals show up - I might even go the parts express route and make my own (would be first time doing a crossover) - I was looking at the c34 plans in the library ....

[fecooper]

Baron030 did an excellent thread on the The N2400 Revealed. He basically refurbished an old N2400 crossover. I followed his lead and procured two used N2400 cerossovers on e-bay and refurbished them with new capacitors from Parts Express. By the time I was finished, it cost no more than if I had bought all new parts from Parts Express, plus I had the extra-plus of having a JBL crossover that matched my JBL speakers. My advice - by the time you buy a circuit board, terminal connectors, faders, capacitors, inductors - it's much nicer and easier to just get some used N2400 crossovers and replace the capacitors.

[Baron030]

If you are going to build all new N2400 networks from scratch, then consider updating the original design to include charge coupling and bypass caps as well. Here is a revised schematic:

Baron030

[fecooper]

Do you think the bypass capacitors on the LF really make that much of a difference? JBL never seemed to think the D130 speakers needed a bypass capacitor.

[33 1/3 RPM]

If you are going to build all new N2400 networks from scratch, then consider updating the original design to include charge coupling and bypass caps as well. Here is a revised schematic: Baron030

Baron, I've never ever seen a X-over with an external voltage. I'm totally confused. RSVP, thanks, Marty

[script56]

If jbl speakers were really all 8 ohm despite label? Why would collectors demand the more expensive 16ohm version? And what tap do you use on amps for jbl speakers, 8 or 16 on amp?

[Bumba]

So, the attached schematic would be correct for my case? Thanks.

[Baron030]

Hi Bumba

I did a little looking around and it appears that 1.4 mH is not a stock off the shelf size. Which means that if you were to replace your existing JBL coils, you most likely need to order a larger 1.5 mH coil and then remove winding to bring the inductance down to 1.4 mH. To be honest, I am only guessing that your existing JBL coils has an inductance of 1.4 mH. If you plan on replacing the JBL coils with something else than you will need an inductance meter and would need to measure your coils. And order replacement coils according to the actual measured value. And keeping the DC resistance of the replace coil a low as possible (under 0.5 ohms).

If it was me, I would not replace the JBL coils and just replace the L-Pads and Caps and add the 5 ohm resistors.

Baron030

[berga12]

I'm Replicating C34 design speakers, I'm wondering if 6uF series on the 2402 are too big for the diaphagram (I know JBL developed like that....) but why cutting so low the 2402?

thanks
Luca