I picked up a pair of 4430's recently that came with four spare 2426H compression drivers. One of the drivers is labeled 2426HAPL. I was wondering what the "APL" refers to and was this possibly pulled from a factory built cabinet? Also, it is missing the foam that goes underneath the 3 bolt adaptor. Would I get the faom from JBL or??? Also, would I be able to install it or would that be left to a tech? Oh, it measured 3.4 ohms DCR so I assume it works though I have yet to try it. Thanks!
I had an epiphany, of sorts, does APL mean Aquaplas?
Why don't have the back cover off it yet? Need a screw driver?
If we knew what the hell we were doing, we wouldn't call it research would we.
Been cookin' breakfast for the grandkids. I will get to it shortly.
I wasn't adventurous enough to remove the diaphragm. Maybe later today?
APL was a horrible computer machine language taught in the early 80's...ugh..
PL means protector-less according to JBL, not sure why there is an A included. H is the ferrite-used ID for 8 ohms, A was for the alnico (2421) and BOTH were used in the 443X series monitors in different generations.
I have owned and seen many of these - that is the standard packaging when the drivers are used in complete systems such as the studio monitors and SR boxes. The 2425HS driver that preceeded this one is identical and I have seen some unique numbers stamped on them when they were assembled into the urei "C" generation large monitors. JBL also sold these drivers to community for their PA boxes with unique numbers ( which usually were stickered over )
The foam between the adapter and driver is the same crap that is used for the foam surrounds and it rots away into a tar-like goo. When we found them like that we would chem strip all of it off and cut closed cell foam gaskets by hand.
sub
Thanks a bunch for the info sub, I appreciate it! So I would looking to cut some closed cell foam to fit? Where would I be able to get the right foam and what thickness would I use? Any help and guidance would be welcome. Thanks!
the tear-off sections of 1/4 packing foam at staples will work. just cut with scissors and you're done. some of us have used stick-down industrial carpeting too.
Thanks again sub, I will give it a try.
This begs the question, just what is that foam for? Both of my 2426's have just goo...
Mike Scott in SJ, CA
Drive 'em to the Xmax!
I'm guessing it's in essence a gasket?
Ah, for sound dreading off of the back of the diaphragm???
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