mikebse2a3 Posted February 15, 2005 Share Posted February 15, 2005 First I know I saw a thread where some where talking about various JBL and Altec Horn Drivers but I can't seem to find it so if anyone knows which thread it was I would appreciate it. Maybe if some of you that know alot about these JBL and Altec drivers could spare some time and sum up some of the advantages and disadvantages of any of these drivers ie: Like low and high crossover limits and such in one thread it would really be helpfull. One reason I'm curious is I just traded for a pair of JBL 2421B drivers for repairing a friends amp. They had come from some PA cabinets and did make some sound but we weren't able to listen to them properly and the BUG screens are bad in them so I took them apart to check them out more and the diaphrams have been replaced with something other than the orginal JBL from what I can tell because the info I found on them so far from the JBL website say the surround is diamond shape and these have more of a radial/spiral looking surround. I called a local rebuilder and he wants $265 each to rebuild so can anyone tell me a good source for parts? Also How do you get to the BUG screens to replace them and clean out the pathways.(Is it just a matter of taking out the diaphram screws and seperating this plate from the driver)? Any info and suggestions are appreciated mike Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 15, 2005 Share Posted February 15, 2005 Interesting, since Jammin' Jersey has 2420 drives with 2421B diaphrams for $200 each. Marvel Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 15, 2005 Share Posted February 15, 2005 That's WAY too much to rebuild the drivers. Radian brand replacement diaphragms, made in California, are about $60 each. Replacement is easy, you can do it. Don't worry about the bugscreen, just remove any frayed ends that may remain with a tweezers. Lots of people think they sound better sans the screens. Not me but it doesn't hurt inless you actually are worried about bugs crawling up there. I think the driver has to be demagged to disassemble. The driver may need remagging though, astute and experienced hornys report that any Alnico magnet driver that has blown most likely has a weak magnet and that will effect the high frequencies. Go to the forum at www.audioheritage.org That's where you'll find some very knowing JBL and Altec fans. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted February 15, 2005 Author Share Posted February 15, 2005 Thanks TBrennan Yea I thought that seemed pretty high. Have you heard them with the Radian diaphragms? How do they compare? Do you know what the lowest freq. this driver can be used at when properly loaded by horn? Thanks mike Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 15, 2005 Share Posted February 15, 2005 Mike---IMO the Radians sound just as good as the JBL aluminums and better than the newer JBL titaniums. Some disagree. You can run the driver down to 500hz on a proper horn, an Altec 511 say. Use a crossover of 2nd or higher order though, IME 1" JBLs are more prone to clacking when run low than 1" Altec drivers. But I've run 2420s on 511s VERY loud with no problem at 500hz 3rd order. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted February 15, 2005 Author Share Posted February 15, 2005 Thanks TBrennan I meant to ask any suggestions on where to get the Radian diaphrams? The ones in there look like they have hit the phase plug and although they work I'll probably replace them and try to clean out the air passages at that time. These drivers need some good cleaning! they sure don't look as good as the ones in your picture! Again thanks for the help! mike Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 15, 2005 Share Posted February 15, 2005 Mike---More money than I thought. http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=294-722 Quote Link to comment Share on other sites More sharing options...
Deang Posted February 16, 2005 Share Posted February 16, 2005 Tom, what is "clacking"? Quote Link to comment Share on other sites More sharing options...
TBrennan Posted February 16, 2005 Share Posted February 16, 2005 Dean---That's the sound you hear when a metal diaphragm compression driver is overdriven. Turn it down quick! Quote Link to comment Share on other sites More sharing options...
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