http://www.apexjr.com/speakerstuff.html
The JBL crossovers. I emailed them about the crossovers and here is what I was told.
On all 4 of the crossovers the chokes are not marked, however
The picture with the 2 x-overs have these parts
1 – 1.2ohm 5W & 37.5ohm 5W resistors 16uf 100Vnp & 20uf 100Vnp electolytics
and 2- 3uf 250V blue poly caps
Other rectangle crossover has the following;
1ea 7.5ohm 5W & 2.7ohm 10W Resistors,1 ea 7 uf 250V blue poly caps & 15uf 100V
electrolytic.
The 2 crescent shaped x-overs both have 6.8uf 100V caps and the larger one has a
3 ohm 7Watt resistor
All 4 have dual gold plated red/black push binding posts
Anyone have any ideas?
The JBL crossovers. I emailed them about the crossovers and here is what I was told.
On all 4 of the crossovers the chokes are not marked, however
The picture with the 2 x-overs have these parts
1 – 1.2ohm 5W & 37.5ohm 5W resistors 16uf 100Vnp & 20uf 100Vnp electolytics
and 2- 3uf 250V blue poly caps
Other rectangle crossover has the following;
1ea 7.5ohm 5W & 2.7ohm 10W Resistors,1 ea 7 uf 250V blue poly caps & 15uf 100V
electrolytic.
The 2 crescent shaped x-overs both have 6.8uf 100V caps and the larger one has a
3 ohm 7Watt resistor
All 4 have dual gold plated red/black push binding posts
Anyone have any ideas?
Netlist said:Hi, DJNUBZ
It's impossible to tell with only this info.
Yes, we at least need a schematic to reverse engineer them!
DJNUBZ said:
I have traced the circuit on these (3rd order with a zobel across the woof), but haven't had a chance to measure the inductors yet. Once i have i will post the schematic and we can start guessing the XO (which of course is very dependent on the drivers JBL was using) -- Steve will also get a copy -- least i can do for him tossing one in with my last order so i could look at it.
dave
Banned
Joined 2002
JasonL said:you drew out in 5 min and me 30 min
I don't think it took me that long
dave
Banned
Joined 2002
Banned
Joined 2002
Banned
Joined 2002
Well, without knowing the VC Re and inductance, it is impossible to calculate the effect of the RC network on the woofer part of the circuit, so that part will have to be redone unless you use exactly the same drivers in the same enclosure as the crossover was designed for.
As for the rest, it is a standard 3rd order layout, but as Dave suggests, the component values look a little strange. Your best bet is to get one of the PC based crossover sims and model it, to see what happens.
As for the rest, it is a standard 3rd order layout, but as Dave suggests, the component values look a little strange. Your best bet is to get one of the PC based crossover sims and model it, to see what happens.
I called JBL and, according to the somewhat helpful contact, the xover is at 2000hz. The JBL price is listed at $53 per unit so at $2.50 these babies are a steal!!!
I recently installed this unit in a bookshelf system and they seam to work fine. There are pre-wired leads off the woofer side so hookup is a snap.
I recently installed this unit in a bookshelf system and they seam to work fine. There are pre-wired leads off the woofer side so hookup is a snap.
DJNUBZ said:is that at 4 ohms or 8?
Given the small value of the caps on the hi-pass its gotta be 8 ohm for the tweeter, and i expect the woof would be the same.
dave
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- Can someone tell me what freq. these crossovers are at?