Recapping L100A’s

[a_mozart]

I’m going to be recapping the cross overs on my JBL L100A speakers, that I inherited from my father, who bought them new a year before I was born. My question is on the new capacitors, The L100A is spec’d with a 8µF cap I was only able to find a 8.2µF cap as a replacement. How big of difference sound wise is this going to make? I love these speakers and want to preserve the sound. Before I do the work should I look for the 8µF and not mess with the 8.2µF cap?

Thanks in advance

 

[KKnight]

8.2 is fine. What you want to be concerned with is the quality of the caps you replace. You want to obtain the
best poly audio grade you can afford and do not replace with electrolytic if they are lytics now. And replace
the resistors with wire wound audio grade. Use the same inductors- dont replace them. Dont have a pic of your XO in front of me.

The idea is if youre going to go thru the hassle, is to gut the cabinets completely, check the speakers
themselves (spider wires and foam supports), replace any stuffing with acoustically transparent stuffing,
re solder any wires and connections so you dont have cold solder joints, fix any loose screws and holes,
and lightly sand the outsides of the cabinets and refinish them with polyurethane or other protective coating.

There is a 10000 threads and web sites etc on how and what to rebuild a XO with, and restoration.
Youve got a lot of research to do.

Parts-Express is a good place to start sourcing your parts.

 

[rothwellaudio]

...replace any stuffing with acoustically transparent stuffing...

If the stuffing was acoustically transparent, wouldn't that mean it does nothing?

 

[KKnight]

If the stuffing was acoustically transparent, wouldn't that mean it does nothing?

What? Youre a audio concern and dont know the engineering and reason for acoustically transparent stuffing?
Engineered and put on the market, now common, about 25 years ago. Wont decrease the internal mass and volume specs for
the speaker, cabinet, and XO design.

 

[rothwellaudio]

What? Youre a audio concern and dont know the engineering and reason for acoustically transparent stuffing?

Correct, I don't.
An acoustically reflective material would reflect sound waves. Acoustically absorbent material absorbs energy from sound waves and turns the energy into heat. "Acoustically transparent" material means material that doesn't reflect or absorb sound waves, at least that what it means to me. If it isn't reflecting or absorbing, what is it doing?

 

[NH-MAN]

What? Youre a audio concern and dont know the engineering and reason for acoustically transparent stuffing?
Engineered and put on the market, now common, about 25 years ago. Wont decrease the internal mass and volume specs for
the speaker, cabinet, and XO design.

Why would you replace the stuffing when it was put there for a reason and was designed with it. Not what I would do unless I was just experimenting for some reason.

 

[Scott75s1974]

Not an electrical engineer. But I'd caution against using polyurethane on anything except floors. If touch up or refinish is necessary, I'd use a Watch danish oil. Others swear by Restor-A-Finish. Those are much more forgiving and less radical fixes. Urethanes are forever.

 

[a_mozart]

Thanks for all the insight. The cabinets are in pristine condition still, and still have the original cover frames (not the foam, that disintegrated long ago), As for the condition of the speakers are also in superb condition, they were never played too loud and since I’ve had them I’ve lived in apartments, so they were always played at low levels otherwise the neighbors would complain. The cross overs are very simple, consisting of a 8 uF cap and l-pad for the mid and a 3 uF cap and l-pad for the high, not fancy. I have replacement l-pads but am considering just cleaning the originals and replacing the caps. From what I’ve seen of the research I’ve done the wiring is pretty robust, we will see when I get into them this weekend. While i’m in there I will be replacing the posts with more robust gold plated ones, as well as replacing the foam around the tweeters.