1 Attachment(s)
Re: 4343 VS 4345 network?
4343 Schematic
4345 Schematic
The 3144 and 3145 networks are the same.
The 4345 originally used the 2421B compression driver. Later production runs used the 2425J compression driver.
I have several brand new 2122H transducers for sale.
Send me a PM if interested.
New caps and resistors for 4343
[Earl K replied:
- Looking at the above image ( which you posted ) suggests that the midbass blending in your setup is suffering from a combination of destructive effects . ]
It will be an easy task to get the 10 inch 2121 center to within a quarter inch of the center to center to the 136A. All I have to do is flip the bottom enclosure. This will however place the port close to the floor. I can make a bigger baffle for the upper three drivers also.
I will be using a 24/0octave at 300 cps Marchand
XM44 and can also go to the 12k crossover with active components in the XM44. I had been considering doing a crossover at 1200 cps between the 10 inch and HF drovers but now it seems tha it should be put at the horn to slot radiator point.
I do want to update the caps and resistors, keeping the JBL provided inductors.
All resistors would be 1% Mills 12 w non inductive, parallelled for power handling where necessary.
I would be replacing the 20uF, the 13.5, the 4 , the 1.5 and the 1.0uF caps. (I have no 52 or 72 as that point is biamped). I do not know what the origonal JBL crossover is using. The three largest values are paper wrap and look like wax filled ends. What type are they?
I can go Dayton 1% metallized polypropylene,
Sonicap polypropylene, or
Claritycap polypropylene. I found a post in another thread referencing a guy in the Netherlands who tried and "reviewed different caps. As would be expected, most are not readily obtainable and some that were cost prohibitive. He did like the Clarity caps despite the "realtively low cost"
I have been searching for a source of polystyrene jumpers but cannot find one. Anyone know of one?
Anyone have a preference in the above 3 brands or feel a different brand is better for the horns and 10 inch? I have studied the threads on using a 9 v biased network but am a little leery of taking that step, especially with the inductor changes and the need to recone the 2121 drivers to convert to a 4345 setup.
- When using the 3143 network, keep in mind that the networks' slopes & the Xover points are partially dictated by the physical layout of the components . The maintenance of original driver spacing is necessary so that the network can create the proper blend between the drivers .
So when making a substitute 4343 ;
(i) The distance from center of woofer to center of mid-driver should be the same as the original system .
(ii) The N3143 was designed to filter a 2121 that is set into a large baffle. The smaller baffle ( in your case ) brings with it less LF loading ( so a bit less output in the lower range ). You might try reducing your hipass slope on the 2121 from 12 db to 6 db to see if this recaptures any lost energy in this area.