L-100 fund raiser project

[Donald]

Don C,

Just want to be sure. Electrically each, new cap is in parallel to one of the existing caps?

Another question. If the shafts of the pots were 1/4" too long, why couldn't you just cut off the 1/4"? Or was the threaded part too long?

[Zilch]

Noting that JBL shows .01 mfd. bypass caps on the PT800 (Marketplace thread,) I'm wondering why we're using 0.1 mfd. here. Is it a better choice?

I know, there's threads and threads about bypassing here, but cut to to bottom line for us, please....

[Don C]

The shaft length could not be shortened easily because the extra length was on the threaded part of the shaft. I wanted the knobs to still fit well, so I did not want to cut the front part off. Adding the extra material was the first easy thing that I thought of that would work, so that's what I did.

The caps are in paralell with the original caps. You can tell if you follow the colored wires from the original caps, the new ones go to the same terminals.

I was guess that I was supposed to order .01 caps but I screwed up the order. I could have sworn that .1 was what JBL was using. I didn't even notice that I was wrong until you pointed it out. I don't think that it will make much difference, being such a small change. But I can change them if there is a good argument to do so.

I have the L-100s back here now. I am working on cleaning up all of the old glue and velcro from the grille frames so that the new foam will sit flat.

[Mr. Widget]

JBL has used both .1 and .01 as bypass caps in various designs. I doubt it makes any difference.

Widget

[Donald]

My xover has a terminal strip pressed into an aluminum channel. The aluminum has a white powder on it. I assume it is oxidation.

[droh]

Hey Don,

Try using Goof Off (available at hardware stores and Home Depot) to remove that glue and old foam. It worked like a champ for me on my L100 frames. Give it a few minutes to soak in and then scrape with a plastic putty knife. You might be able to do it without losing the black fabric, but I just replaced mine.

[Zilch]

Seems a major point of having the fabric there is to provide a glue point for the grille in the center of the woofer. The fabric doesn' seem to give much support. I'm thinkin' of using fiberglass window screen instead, maybe.

Any thoughts?

[sonofagun]

Having had much experience with the old frames and installing new grilles onto them, IMO the purpose of the fabric is to provide support to the back of the grille foam (prevents excess sagging or flexing) as well as providing a little added protection for the drivers.

I would recommend using f'glas window screen fabric also - stretch and staple in place.

Sounds like a good tip for removing old glue and foam. A sharp chisel or scraper works too.

[Don C]

They are coming along, slowly. It will probably just be a few more days before they are done. Here is a tweeter being refoamed.

[Don C]

Here is one that is finished.

[Don C]

I have always hated the style of connectors that JBL used on these speakers. While I have them apart, I decided to retrofit some decent binding posts. Here are the parts. New and old.

[Don C]

I have one of the grille frames glued up. I will probably do the other one tomorrow. Here it is, taking over the dining room table, while the glue dries.

[Audiobeer]

Great job Don!!!

[Don C]

This is the glue that Sonofagun suggested. It is the same stuff that is used for gluing laminated counter tops.

[Audiobeer]

That blue cloth is going to look slick baby!