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View Full Version : To gauss or not to gauss



Donald
11-16-2004, 08:00 PM
Gauss!!!

Dropped of pairs of 136A, LE14A and LE85 at OCS to get zapped. Will pick them up Friday.

If this improves things I will get my other pair of LE14As and 9 123As done.

Should I consider doing the LE5-2s? How about the other LE5 models with the flat magnets?

I have a pair of 2212 but I don't think they are Alnico.

scott fitlin
11-16-2004, 10:43 PM
Alnico magnets may lose some charge over time, especially if they lived and hard, abusive life. Ferrite magnets, however, do not lose their charge, and should be just as good as when new!

imtkjlu
11-17-2004, 01:02 AM
30 years old 075/LE85/2205A are they Alnico or Ferrite :confused:

Zilch
11-17-2004, 01:32 AM
They be Alnico.

Tom Loizeaux
11-17-2004, 05:23 PM
Please let us know how the re-gaussing went and what you hear once you get them back!
Thanks,

Tom

imtkjlu
11-18-2004, 12:56 AM
Is there a easy way to se if a magnet is Alnico or Ferrite http://audioheritage.org/vbulletin/images/smilies/confused.gif

Tom Loizeaux
11-18-2004, 08:20 AM
[QUOTE=imtkjlu]Is there a easy way to se if a magnet is Alnico or Ferrite

Yes, the Alnico magnets are usually inside a metal can. JBL rounds the rear of these covers and often uses a wrinkle paint finish. The ferrite magnets are much larger and look more like large discs of metal. Most of the JBL pro drivers that use ferrite magnets have the letter H behind the model number, while the Alnico versions do not.
Visit the JBL Library and go to photos of these componants. You'll see the differances.
Hope this helps.

Tom

Donald
11-26-2004, 08:46 PM
Well, so far I see no improvement. The LE14A in the L222 Disco still appear to bottom out when driven moderately.

The L300s need a bit of work before I re-install the drivers. For some reason there is no sound damping fiber glass on the floor of one unit and the other has some of the stuff Parts Express sells. I want to see if I can find some thin glass batts at a DIY place. I also had to grind off the head of one of the screws holding the panel covering the LE85 driver. The screw appears to have been glued to the T-nut. The T-nut was spinning. Any big deal if I use 5 screws instead of 6 to hold the panel on?

Steve Gonzales
11-27-2004, 01:38 AM
Hey Donald, it sounds like either your spiders are toast or you got a bad re-foam. I can peak 500 watts with my L222's and with LE14A's, LE14H's and LE14H-1's (tried them all) and there are no problems. I wonder if you at least tried the two 100gm weights on the PR15's?. I've got some spare JBL "T" nuts around here somewhere, just let me know what size and I will send them to you. I am a friend of the owner of MB Sound in Bakersfield and will EAT the fee to replace the spiders and foams if you are not 100% satisfied with results! He gives me VERY GOOD prices. I would also let you take a pair of LE14H "loaners" while they are worked on! Happy Holidays!

Donald
11-27-2004, 04:43 AM
Steve,

The guy at Orange County Speaker did talk about sagging spiders. On the 136As. He said the LE14As were fine. And OCS did the re-foam on the LE14As back in 2001, too.

I have a 2nd pair of PR15 and some weights from Widget that I can try. If none of this works, I will try a re-foam from your guy.

I won the auctions for the L200 136As, LE85/H91 and acoustic lens from the guy on eBay. I hope the lens fit the L300. And if my re-gaussed 136As aren't improved, I will try these.

Steve Gonzales
11-27-2004, 11:27 AM
Yeah the L91's One way or another we will get those L222's up to snuff. TTYL,Steve.