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View Full Version : To be or not to be... L-19.



rcpmac
04-19-2004, 06:30 PM
Guy had this big pile of trash in his garage with a speaker box on top that caught my attention. I was thinkng of putting some Eminance 8" prosound drivers for monitors for my kid's band in some medium size tossaway boxes when they showed up.
Well, what showed up turned out to be a pair of JBL L-19's that had been plastic laminated with dark grey P-lam and had wall hooks screwed on the back and rotted surrounds and still had the baffles intact.
I read some favorable reports here on the L-19, but the LF driver 116A, construction looks wimpy to me. (I don't really know) So I can get the surrounds and fix them up for $25, or stick the Eminence drivers in and use them as monitors as planned. What do you think?
Should I save these speakers, or call them a loss and plug in the eminence units and perhaps chop the boxes into wedges?
Can the crossover handle some real power?
Here is the eminence unit.
http://editweb.iglou.com/eminence/eminence/pages/products02/speakers/beta8.htm

boputnam
04-19-2004, 07:22 PM
Hey...

The L19 is the consumer version of the 4301B - my personal favorite (this is a redundant post in that regard...).

I would not swap-in alternative brand components, and I would urge you not judge that LF on "appearances". Akin to the frustration mikebake has introduced on a separate Thread, there is a method to JBL's madness of mating components with specific cabinets and networks. Granted JBL may have offered too many options to the market - but being wizards empowered by providing acoustic ecstacy in many forms/formats, who amongst us would not have done so... ;) - but their products were well founded.

Re-surround / or get that 116A resurround, and enjoy.

re: power rating, if you refurbish these, follow the manufacturers power handing guidelines. For higher SPL, you need move-up the food chain.

4313B
04-19-2004, 07:27 PM
"the LF driver 116A, construction looks wimpy to me"

Yep, I consider the 116A one of those great little success stories. Despite its obviously low budget construction compared to other JBL 8-inch transducers of that era, it performs admirably well. I personally like it quite a bit better than it's larger 10-inch sibling the 125A/127A.

*****

"there is a method to JBL's madness of mating components with specific cabinets and networks"

Yes, there most definitely is.

rcpmac
04-20-2004, 05:43 PM
I guess you just saved a pair of L-19s and my project list grew by one.
Question;
I have observed on a couple of DIY re-surround sites, that the surround is glued to the front surface of the cone. On the l116, the original is on the backside.

Robh3606
04-20-2004, 06:03 PM
Carefully remove the old foam from the back of the cone and just install the new foam over the scar. DO NOT put it on the front side.

Rob:)

rcpmac
04-21-2004, 09:22 AM
Thanks, And how about the idea of using a "D" cell battery attached in reverse polarity for centering the voice coil? Is this approach legit vs the shim technique?

boputnam
04-21-2004, 11:59 AM
You can't use a shim on a resurround - the spider has not been tampered with so you can't get to the gap.

You should run a 30Hz test tone through the transducer during gluing to ensure the voice coil is centered. CD's with test tones are available in a number of places. One that come to mind is http://www.stryke.com/basszone/testcd.html - works fine. However, my Google also turned-up this Win software which suggests you could burn test tones to CD's at-will...

If you get your kit from Rick Cobb, he might through-in a handy-dandy test CD if you're nice to him... :yes: rcobb@tampabay.rr.com

rcpmac
04-21-2004, 12:10 PM
I will ask about the tone generator CD. I suppose I could use my digital keyboard at the "B" (30.8 Hz.) with a simple synth tone.
My understanding from the DIY sites was that you remove the dust cap to shim the cone and replace with new.

boputnam
04-21-2004, 12:31 PM
Ah, and that you certainly can do. Tricky, and tedious but it is doable.

I've had good luck using the test tone, and your keyboard idea is a perfect workaround. :yes:

But, if you're going to all that trouble, why not recone? That's preferred...

Lots of parallel threads out here today... :duck:

rcpmac
04-21-2004, 08:48 PM
Reply from Rick Cobb,

Chris,
I do not have the LE25 tweeter parts.
The "b" note would work fine for a test tone.
Forgetabout the battery!
Best,
Rick C.

The cones are in great shape. I think the $19.95 and 1hours work will be an appropriate fix for these speakers.

boputnam
04-22-2004, 06:57 AM
Originally posted by rcpmac
Reply from Rick Cobb Ain't he great? :yes: