JBL 4435 restoration

Ingenia

New Member
Hello to all the people.
I'm new in this forum. I present my project of restoration of the big boxes JBL 4435
First doubts:
The membranes work correctly, but they are different.
In case of replacement, which is better? Genuine JBL or Radian?
The foam behind the membrane is damaged. What to put here?
IMG_20190209_220810.jpg IMG_20190205_105133.jpg
 
@Alobar will have the info you need. I’m about to start a similar repair and planned to use some air filter foam I have from another project which he said should do the trick. Keep us posted, keep the pics coming and welcome to AK!
 
Hello to all the people.
I'm new in this forum. I present my project of restoration of the big boxes JBL 4435
First doubts:
The membranes work correctly, but they are different.
In case of replacement, which is better? Genuine JBL or Radian?
After dinging one of my diaphragms I ordered a pair of Radians which had an almost identical sound to them.. I replaced one and compared a/b to the other and I would be hard pressed to hear any difference. I'd say either would be just fine and the Radians are a quality product made in USA. I'd avoid any of the ones made in China however.
 
Radians are a quality product made in USA

Speaking of that, If you do decide on JBL parts, give them a good visual check. Check the DC resistance as well. They had a few QA issues when they moved production to Mexico. Hopefully it's fully sorted by now.
 
You have 4435s with AlNiCo 2421s??? That has to be a rarity from right at the beginning of production.

The correct diaphragm is the 2421 and not the 2425, though it will certainly work. The 2421 is aluminum and the 2425 is titanium. The aluminum is smoother (and highly valued), but will not take as much power, and not go quite as high as the titanium. But, there are many, myself included, who prefer the sound of the aluminum to the titanium.
 
Get the Radians over the titanium, they are much smoother, and nicer. I had a direct comparison between the Radians vs JBL titanium diaphragms in my LE85. Between OEM JBL and Radians, I could not tell the difference. So, it kind of depends if you're a purist or okay to mingle.
 
That’s the ideal speaker driver load in my opinion. The SFG woofers have lower distortion than their AlNiCo motor predecessors and the 2421’s sound better than what came after them.

Both of those diaphragms look like JBL aluminum to me but closer pictures would be helpful. The rings are on again off again anodized so I doubt they are from the same run / age.

You need someone to properly test them to see if they match in performance. They may be fine.

I replaced the surrounds on my 4435’s with butyl rubber surrounds and would do that again in a heartbeat. I posted all about that on the Lansing Heritage forum.

What condition is the rest of it all in?

Barry.
 
The dreaded "vampire bites" to which I often allude! Maybe even a few. This is caused by the spade lug on the input wire being attracted to the magnet and hitting the diaphragm in doing so when someone wasn't careful. Someone was in there after the factory.

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