Originally Posted by
Eric M.
I have always heard the JBL crossovers labeled "16 ohm" were no difference than ones with no impedance labeling, ie. N7000 vs N7000 16 ohm. I finally decided to have a look for myself. An older N7000 16 ohm popped up on e-Bay and I grabbed it. I took the parts out of an N7000 and the 16 ohm version for testing and comparison.
Although any caps from crossovers of this vintage are probably out of spec, the caps did have the same part number, #10460. the only difference was one were wax filled, the other, epoxy filled. From the JBL literature, that part # corresponds to a 1.5 uF cap. That also matches up with the JBL schematic from the JBL site that we have all seen.
I'm assuming if the caps match the N7000 schematic, the coils should also for proper crossover. And the specs of a coil should not change with age, like with caps (is that correct?)
Here is what I got:
Older N7000 16 ohm crossover: coil part # 10421, measure .503 mH and .506 mH
Newer N7000: coil part # 13219P (and) 16265, measure .570 mH and .566 mH
The only part number I can find was 10421, which corresponds to a coil in a 4412 speaker crossover and is rated at 1 mH. (I'm assuming this is an example of JBL recycling part numbers?)
Both are fairly close to the .6 mH shown on the N7000 schematic.
What do you guys think? Are the "N7000" and the "N7000 16 ohm" crossovers the same? I'm not very good at reverse designing crossovers, but I'm guessing if those coils in the older N7000 16 ohm were meant to be .5 mH, I doubt that would make much of a difference in the crossover, not enough to account for a 16 ohm speaker vs an 8 ohm.