Overcoming foilcal-a-phobia
I overcame the foilcal-a-phobia last night and removed the foilcals from the L-150's I sold to my roomie. The mids weren't even coming on until you had the L-pad cranked all the way down and forget the highs unless you twitched it just right. I so not wanted to touch the foilcals that I almost wanted to drilled a few holes in the back of the cabs and mount another pair of L-pads in the rear.
But on Sunday, I visited Steve Gonzalez in sunny Bakersfield and he told me how to remove them perfectly. The trick is to get a super flexible 1" putty blade (I paid over $5 for the Warner Pro at Lowes) and of course the hair dryer. Man, I had those things off in ten minutes. I have three extra sets of L-pads and after getting the ones out of the L-150's, I noticed that the mounting scheme is totally different, with the two clunky "Noble" brand pots mounted on fibreboard and three screws in a triangle formation to hold them in. Ohming out the "Noble" brand, I could see there was problems, especially ohming it out. While turning the knobs, the resistance was jumping all over the place. I tried popping the backs off (something I picked up here on a Singapore 43xx post) and cleaned it but good. But it still sounded like crap, so I replaced both L-pads on the fibreboard with thinner profile pots off've an L-112 unit (I cleaned this one before and ohmed it out with two others to verify that they're all on the same page).
Ever since I mounted the x-overs permanently to the backs of the cabs and used the in-cab crossover instead of the L-112 unit I had laying off to the side on the bottom, the sound quality had deteriorated. It sounded muddy and lacked midrange strength, because the woofer was really the only thing working well and it covers the lower part of the mids (but not the upper of course). After my switch on the one speaker last night, I was amazed at what it sounded like. The mids are back sweet and strong and you get no dropping out when you turn the knobs. Even the highs are bettah! I am now going to fix my bud's and my little brothers L-150's as well as my L-300's now that I've over come the foil-cail-a-phobia. The only pain in the behind will be to remove the old adhesive from both surfaces before using 3M Spray adhesive on the back of the foil-cal.
Thanks Steve for your help! (his four L-220/L-222 set up sounds pretty friggin' radical!)
Does that reading apply to all L pad pots?
Will those ohm meter readings apply to the pots on the 4311's also?:blink:
My name is Izzy, and I'm a foilcal-o-phobe.
I finally had to join a foilcal self-help group. In 1972 my 4310s arrived with wiring errors. That’s right, JBL quality control failed to catch a wiring error. As I recall the mids didn’t work at all. I still have the detailed drawing I sent to JBL to show them how the mistake had been made.
So my 4310s had minor ripples in the metal from the get-go.
Now, in storage, they need new L-pads, and I am deathly afraid of thrashing these even more. Thanks a bunch for the heat gun and putty blade suggestion, and the re-gluing tips as well. I may now finally get up the courage to fix these speakers. This will save me big bucks in therapy.
Now all I need is a good way to repair broken grill cloth frames (some 4310 owners will know just what I’m talking about).
http://IzzyWeird.com/images/eyes1.jpg
Izzy
