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warpig
05-04-2008, 12:07 PM
Hello All

I have a pair of L166 speakers. The L-Pads are a little scratchy and while I am in there I would like to replace the caps. This will give me a little practice and some learning’s for rebuilding the crossovers on a pair of L300’s. With that being said I have done some research but I still have some questions that I am not sure about and would appreciate some help.


For example on the L166 there is a 8uf and a 4uf cap. The caps I am looking at I cannot find in the 8uf value. I know I can use 2 4uf caps but this seems to drive up the cost on this rebuild and other builds (L300 charged coupled). So what would be the consequences of using a value that is a little off on the caps? 8.2uf vs. 8.0 also if someone could point me to a book or anything to explain what the change would be. Higher/Lower crossover frequencies?
Can some one point me to the original crossover schematic for the L300? I have the one to the L166 from here. (http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L166%20ts.pdf)
When building charge coupled crossovers are the quality of the caps as important? For instance from what I can see there are quite a few more caps in the charged coupled than in the others (bandpass). I guess what I am trying to say is. If using charged coupled could you use cheaper caps? If you use better caps for say the bandpass would it equal the charged couple in sound?
I understand there are a lot of variables in play here. I am not a poor man but neither am I a rich man. Just looking for the best value for the money.

Appreciate the help.

Mannermusic
05-04-2008, 09:29 PM
Hello All

I have a pair of L166 speakers. The L-Pads are a little scratchy and while I am in there I would like to replace the caps. This will give me a little practice and some learning’s for rebuilding the crossovers on a pair of L300’s. With that being said I have done some research but I still have some questions that I am not sure about and would appreciate some help.
For example on the L166 there is a 8uf and a 4uf cap. The caps I am looking at I cannot find in the 8uf value. I know I can use 2 4uf caps but this seems to drive up the cost on this rebuild and other builds (L300 charged coupled). So what would be the consequences of using a value that is a little off on the caps? 8.2uf vs. 8.0 also if someone could point me to a book or anything to explain what the change would be. Higher/Lower crossover frequencies?
Can some one point me to the original crossover schematic for the L300? I have the one to the L166 from here. (http://manuals.harman.com/JBL/HOM/Technical%20Sheet/L166%20ts.pdf)
When building charge coupled crossovers are the quality of the caps as important? For instance from what I can see there are quite a few more caps in the charged coupled than in the others (bandpass). I guess what I am trying to say is. If using charged coupled could you use cheaper caps? If you use better caps for say the bandpass would it equal the charged couple in sound?I understand there are a lot of variables in play here. I am not a poor man but neither am I a rich man. Just looking for the best value for the money.

Appreciate the help.

Re the L166 questions: Remember, the caps in the crossover are +/- !0% so, for a nominal 8 uF cap anything from approx. 7.2 - 8.8 is "in spec." If it was me, I'd replace the L-pads with new (8 ohm, 15 watt, !" shaft), and add .01 by-pass caps to the existing JBL caps for starters. Adds some nice clarity and smoothness. The "best buy" in caps, as far as I know, are the "Dayton" brand from Parts Express, www.parts-express.com (http://www.parts-express.com). All the available schematics are in the Technical Reference Section at the bottom of the initial site "Table of Contents" screen. See Tech Sheet Links in the lower rt. corner. Mike

duaneage
05-08-2008, 10:11 AM
I'm not a fan of the 30 dollar a piece capacitor. Sure, they are higher quality but I think it's hard to measure the difference in a speaker system and still harder to tell the difference without careful A-B test conditions. I use Solen caps because they are well made, easily available, and come in a variety of values without breaking the bank. Even the lowly electrolytic s are better than the original 30 year old capacitors. IF your experimenting it might be wise to test with cheap electros and then when your satisfied with the results build a quality network that will be durable and trouble free.