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Guido
05-31-2003, 03:37 PM
I followed some discussion about the polarity convention of JBL Speakers but I'm still not shure how to connect my 3143 Network. :mad:

Can one of you give advice?

I will use:

Bass 2235H (negative)
Mid 2012H (positive)
High 2420 (?)
UHF 2405 (?)

Thanks, Guido

4313B
05-31-2003, 04:38 PM
positive voltage to red terminal of 2231
positive voltage to black terminal of 2121 (in your case just the opposite)
positive voltage to black terminal of 2420
positive voltage to black terminal of 2405

Guido
05-31-2003, 05:39 PM
Thank you Giskard!

Where do you take your informations from? Do you have acces to the internal network of JBL?

Anyway....

Isn't the 2235H negative? This means pos. Voltage to red. Am I right?

4313B
05-31-2003, 09:24 PM
"Where do you take your informations from?"

The Oracle at Delphi

"Isn't the 2235H negative? This means pos. Voltage to red. Am I right?"

Positive voltage to the red terminal causes the 2231A/H and 2235H cone to move inwards.

Guido
06-02-2003, 12:22 AM
Hello again Giskard!

I once was at Delphi but they didn’t tell me anything about JBL speakers J

To my question:
OK, 2231 and 2235 is clear now

To compare the 2121 to my 2012 I need one more information:

Does the 2121 behave like the 2231/2235? This means pos. Voltage to red Terminal causes inward movement?

4313B
06-02-2003, 05:44 AM
"Does the 2121 behave like the 2231/2235? This means pos. Voltage to red Terminal causes inward movement?"

Yes :)

Tom Loizeaux
06-06-2003, 09:28 AM
When I return the crossovers from my 4343s to their cabinets this weekend I will follow JBL's schematic and original wiring - except that I will reverse the wires to the actual driver terminals. That will keep everything correct in terms of crossover input direction yet get my drivers in phase with all of my other amp/wiring layouts.
If you need confirmation on JBL's original wiring code, let me know.

Tom

Tom Loizeaux
06-07-2003, 01:56 PM
For Giskard, or anyone...

After looking at the schematic for the 3143 crossover, I'm confused about positive voltage, color coding, correct crossover "direction" and forward speaker movement. The schematic looks as if JBL intended to apply positive voltage to the black input terminals - but it appears that this positive voltage goes to the drivers first and then through the crossover componants as it returns to "ground". Doesn't this seems to defy convention in regards to crossover componant polarity?
So, not concerning myself with componant "direction", Should I hook up my drivers in reverse (green wire to black terminal on the 2231, b&w to black terminal on the 2121, red to black terminal on the 2420, and red to black terminal on the 2405) and then connect the amp's positive voltage to the red inputs, I will have "correctly" hooked up these 4343s to be compatable with current polarity?
Please help clear this up if you can. This is all very confusing.
Thanks,

Tom

boputnam
06-07-2003, 02:36 PM
Hey, Tom…

I’m gonna take a stab at this, but your post was a bit confusing. And, I think I understand you are trying to make this cabinet positive? I don’t know if that is necessary, unless you are pairing it with a cabinet that is positive, or another brand (which will be positive). But if that is your objective...

Looking at the 3143 network (new to me…), it looks like “Red LF” goes thru to the GRN wire for the LF, so the positive signal is going to the red terminal on the LF. The LF is the 2231A (or H), right? I’m pretty certain the 2213A (and H) is negative (cone in on positive), so this would indeed be a negative cabinet. The three other componets (all likely negative) are in-phase with each other but out-of-phase with the LF.

Anyway, in short all you need do is reverse the wiring at each transducer and you will have put each transducer 180-degrees out of phase with factory design. That will honor the engineered crossover relationships between the components, only 180-dgrees out-of-phase.

Looking at the schematic, it looks to me like the crossover "path" is OK - the signal "works its way" (we're sure to now enter the AC-DC discussion realm...) from the Red input through the caps/inductors/resistors to the transducers, but what might be confusing is for the MF, HF, UHF they use the "negative" wire to change the phase of these components.

Your question on crossover “direction” tags something Mr. Widget and I were talking about the other day. He groks this better than I, but we are in agreement that you should not merely hook the signal hot to the black (negative) speaker (or crossover) binding posts. It is best to do this re-phasing at the component.

Mr. Widget
06-07-2003, 04:25 PM
Originally posted by Giskard
[B]"Where do you take your informations from?"

The Oracle at Delphi



Hey I have an Oracle Delphi turntable too!:D :D :D

boputnam
06-07-2003, 06:18 PM
The Oracle at Delphi

I admit that I too, have chuckled endlessly at this. CL-E-VER!