JBL 4312 A crossover network ?

[jan_slagman]

Hello,

I think i need a little help figuring out what kinda network i recently bought in the States. Seller stated it was a JBL 4312 A network with matching foilcals. The text on the foilcals indeed says "JBL 4312A Control Monitor", but when looking at the JBL 4312 A wiring diagram i'm not quiete sure if these are the corresponding crossover networks. There is an 10391-T 8 MF, an 11937-T 3.0 UF and twice a 0.1K on board and there are two L-pads with CAT40H 8Ohm50dB 8305 printed on the backside.
I want to use those networks with 2213H woofer, 104H2 midrange and 035Tia tweeter. Can anyone tell me if i have the right crossover networks ?

Please let me have your comments.

With kind regards,

Jan Slagman
The Netherlands

[grumpy]

sounds very much like the 3112C schematic on JBLpro website:

http://www.jblproservice.com/navigat...chematics.html

[jan_slagman]

sounds very much like the 3112C schematic on JBLpro website:

http://www.jblproservice.com/navigat...chematics.html

Thanks a lot Grumpy,

I think you're quiet right ! But, is this network suited for the loudspeakercomponents i mentioned before ?

Kind regards,

Jan Slagman
The Netherlands

[jan_slagman]

Hi Grumpy,

I have been looking for any suggestions and i found this:

Re: 4312 C

Consumer model from 1990 to 1998
Consisted of the 2213H, 104H-3, 035TiA, and 3112D

I think this must be the right crossover network.

Kind regards,

Jan Slagman
The Netherlands

[grumpy]

from -C to -D network version, it appears a 0.2mH inductor was added, and a cap
changed from 8uF to 10uF but this could be easily added by soldering
parts in parallel to the existing circuit (0.2mH and 2uF added to each network).

Appears that the slope on the HF circuit was changed (perhaps better
protecting the tweeter) and the MF-HF crossover point adjusted accordingly
(as well as the polarity of the tweeter).

Perhaps the 035Tia was a bit less rugged in this application, or there was
some minor "voicing" of the system with the different drivers. At any rate,
it sounds like it would be worth it to add the correct components.

N3112C -> 4312 -> LE25-2/LE5-12
N3112D -> 4312A(and C) -> 035Ti(a)/104H-3 (or -2, depending on where you look)

[jan_slagman]

Hello Grumpy,

Many thanks for supporting me ! I know what to do now.

Kind regards,

Jan Slagman
The Netherlands

[Rusnzha]

I might be crazy , but doesn't the 2uF cap go in series with the 8uF in this situation?

[Don C]

When two capacitors are placed in a paralell circuit, the capacitance is the sum of the two values. It's the opposite of what you would see with resistors.

[speakerdave]

And inductance in series (to add), yes?

[grumpy]

yep, ignoring possible collocation issues (unintended mutual coupling).