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Need advice for renew JBL L300

Hi all,

I have L300 speakers which I really love,
But due the age I think i can get much better sound if I renew some of the parts,
Starting the LPADs which currently they are quite noisy .
Far as understand I need 16ohm and 8ohm but not sure what to buy.
I found these ones:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-254

and for the 8 OHM:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-252

In addition i'd like to renew the croosover but need advice where to start?I'd like to focus on the critical parts that is recommeneded to replace and just rebuilding the crossover.

Thanks you all!
avico
7 responses Add your response
xiekitchen
821 posts
 
You should be able to clean them with Deoxit spray(from the inside of cabinet or you may have to remove LPAD control alltogether and take it out(?), and just keep working the control back and forth with a flat screwdriver... my original caps in my L-200's work fine so I don't think all the hoopla about capacitators in speakers going bad is all that big a deal... 35 years and these crossovers still sound fine to me... ?? but you could try calling Madisound and asking for their advise, they sell speaker builder parts and helped me with replacing my Spica tweeters years ago.
magfan
1,583 posts
 

lpad link::

http://www.bcae1.com/lpad.htm
magfan
1,583 posts
 
That there are few if any modern speakers made with L-pad attenuators should say lots about 'em.

My panels have jumpers where fixed resistors can be installed. You could do similar and have a place to jumper in resistors to lower the HF output. Though why would you? Setup makes a huge difference.
avico OP
18 posts
 
Thanks Magfan

I'm not sure I want to bypass the lpads cause I think they can be useful especially when I'm moving(living in a rent house) and the acoustics is different.
In addition,I'd like to keep the original design .

Is some1 know for sure what LPADS will fit?I'm asking it again cause it's diffcult to replace them because it's require removing the original aluminium tabs and these are attached to front cabin(the lpad's knob placing right behind it).
tried to remove but the tabs bend easily.
btw-Any ideas how removing this tab without bending it?
magfan
1,583 posts
 
Caps apparently don't age well.
Oil filled? Bees Wax(!) and others can dry over long time periods.
Newer cap designs may pay dividends with better sound. Crossovers are a thing unto themselves. Some guru might even recommend dropping the iron core inductor, if so fitted, and go to air core.

You might want to replace the L-pads altogether with a fixed resistor after getting everything sounding right. Measure carefully!
Some speakers had (have?) a switch for 2 or 3 settings, with different resistor values to be switched into or out of the circuit as needed.
avico OP
18 posts
 
The LPADS are really hard to move,and making lot of noise .
Can you please explain how to clean them?
In case they are total lost(almost sure one of them broken).
Can you please which LPADs can I use instead?

reagarding te caps , some one explain me that all caps have expiration date and speakers that are 35 yrs are must renew with new caps is it true?
any recommenedation is most welcome.
xiekitchen
821 posts
 
I would just have the 'L-pads' cleaned, they are high quality ALPS pots so they are already high quality... JBL also used good quality caps in the crossover so you could leave those alone as well or experiment with some high end boutique type caps.. I have a pair of L-200's and what I did was replace the input connectors/jacks on the back with something high quality and then replace all the interior wiring with better wire.. could be of your choice.. I think that was the stock 'weak point' of the jbls was the internal wiring and the input jacks. Regards and have fun...
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