L112- tweeter distorts SOMETIMES?

[steelyzappa]

I have a pair of L112's. On some CD's the left tweeter only sounds like it's about to have a vioce coil meltdown but it hasn't melted down yet. I then changed the CD and turned down the volume a bit and it sounds fine. Also, I fiddled with the high freq L-pad....it's scratchy and staticy. DO I need to worry and is my tweeter about to blow? Thanks

[boputnam]

Hmm... Nice speakers.

I've not worked on these, but if you're able to swap tweeters cabinet-for-cabinet, that might be a start. You can see if the symptom stays with the cabinet, and not with the tweeter.

But, I've not removed one of those tweets - surely many here have, and can advise...

[steelyzappa]

Swapping tweeters is a great idea!
Thank you!

[GordonW]

Yeah, I'd be suspicious of the tweeter actually being the problem. I'd try carefully cleaning (or replacing) the pots... especially if the tweeter works correctly in the other box. Sounds like it's time for a bath!! :D

Regards,
Gordon.

[steelyzappa]

I read in this forum how to remove the L-pads. DO I have to remove them to clean them and if I do, how do you recommend cleaning them?. Thanks again

[Audiobeer]

I'd try cleaning the L-Pads first. The woofer has to come out either way. If the L-pad cleaning dosen't take care of it just swap the tweeters. If you end up needing a tweeter let us know.

[boputnam]

Hey, Steely...

I was thinking that swapping would enable you to confirm where the problem lies - or at least narrow it down. Maybe that's more work than I realize (those tweets look cosmetically nightmarish to remove...). Regardless, to clean the L-pads is not trivial, and does require removal. JBL did not design these for easy removal.

If you're going to clean, this requires remving from the cabinet, and opening their housings and then working cleaner and maybe some extra fine garnet paper (if the corrosion is really bad) into the contacts, and working it all around. Tedious, and results not always satisfactory.

It may be easier to just replace, anew. Here's a Link to 3 pages of L-pads (http://www.partsexpress.com/webpage.cfm?DID=7&WebPage_ID=3&Start=1&ObjectGroup_ID=196&sm=1&so=2&search_type=19912671&desc=ASC) at PartsExpress - our favorite source. I believe 260-250 is a direct replacement for your cabinet, and less expensive than through JBL. Alternatively, if you have the space ( :confused: ) no. 260-265 is preferred by Giskard and others, but it has a diameter of maybe three-inches - too large for most vintage applications. 260-250 should swap right-in, however, the shaft is slightly thinner than original, so the original knobs need to be futzed with to make them fit (you can VERY CAREFULLY spread the wings on the shaft end to enlarge just enough. But this is very brittle metal and you don't get a second chance).

*****

edited per the correction of Giskard, below. Length does matter... ;)

[4313B]

260-265 is the 8 ohm version of the high power 16 ohm ceramic L-Pad JBL used in the large Studio Monitors on the 8-inch, 10-inch, and 12-inch midrange transducers.

260-255 is the high power 8 ohm version that JBL used in many of the higher powered systems. JBL part number was 58450.

260-250 is the replacement for the ubiquitous JBL part number 10285. Throw it in the trash and use 260-255.

"260-262 is preferred by Giskard and others"

Not me, the shaft is too short.

[steelyzappa]

Man, you guys are awesome! What a thoughtful forum. So many ideas/choices and I thought I was stuck in the mud...LOL.
Regards,
Matt aka: steelyzappa

[boputnam]

Originally posted by Giskard
260-265 is the 8 ohm version of the high power 16 ohm ceramic L-Pad JBL used in the large Studio Monitors on the 8-inch, 10-inch, and 12-inch midrange transducers.

260-255 is the high power 8 ohm version that JBL used in many of the higher powered systems. JBL part number was 58450. Hey, Giskard...

I've had some trouble fitting those 260-265 into spaces where the 10285's came from. Will the 256-255 fit in the 10285 space? Can't tell from the picture, and there's no dimensions given (other than shaft length... :banghead: