J15L

[ncgrove]

Work is slowly moving along. Had a case of strep throat last week, so even though I was home from work with a fever, I couldn't muster up the strength and concentration to do anything. I'm on the mend, and got some more work done.

First I set the staples in the horn sheath. Just used a nail set and an electrician's hammer.

I got the duct braces glued and tacked in no problem. Luckily, I didn't have to do any sanding of the braces, so that was very nice. Before putting in the duct, I brushed down some Duratex in the duct area because it's pretty difficult to get in there once it's all boxed in. I masked off the area on the horn sheathes where the ducts butt against to keep fresh wood for the PL to attach to. Then I installed the ducts, tacking them to the duct braces, and then to the baffle. Everything went well.



This morning, I put in the throat braces, using hot glue. Fortunately these don't have to be perfectly placed, because I found the glue cools down pretty quickly once it hits the plywood. Anyway, things turned out well.



Hopefully I can scram out of work a little early today and go home and staple in a throat sheath.

[ncgrove]

Just got the first throat sheath installed. This guy was a bit of a challenge. I had one staple blow out- the first few staples pulled through the sheath. There's a lot of pressure on the end of the sheath! I pulled the staples in the duct panel and started over, this time putting the staples perpendicular to the duct edge. This worked a lot better. Probably too many staples, but I didn't want the sheath springing back up again. Here's what I've got:

[ncgrove]

Here's what it looks like with one throat sheath all done:



And I stapled in the other throat sheath. Now I'll just let the PL cure until tomorrow afternoon.



The throat sheathes are tough on these.

[Bill Fitzmaurice]

The throat sheathes are tough on these.

Yes, but you only have to do it once.

[byacey]

Wipe the outside face of the wood with a rag or paintbrush soaked with really hot water; it will naturally curve due to the outside expansion, and the hot water also softens the wood fiber for easier bending. Fasten it while wet.

[miked]

Been lurking this thread and figured it was time to give props to fellow Texan. Hello from San Antonio! FANTASTIC job so far; these Jack Lites look like a heckuva challenge; I don't think bendy plywood and I would get along too well. Your method of laying out every single panel line, staple and glue line is well-worth the effort. Very inspiring. Really looking forward to the rest of the build and the final product. Keep them pics comin'!

[ncgrove]

Thanks for the kind words and suggestions. I should say that the throat sheathes aren't conceptually difficult. Actually, they are pretty straight forward. I thought the throat sheathes were more difficult on the J15L than the J10L because of the width, and probably to some extent the length of the sheath. That is, there's a whole bunch of spring to bend and hold steady. Fortunately, things don't have to be perfect because: 1.) The PL will fix most imperfections, and 2.) I'm the only one who will know.

I don't see why anyone who can build a regular Jack couldn't build one of the Jack Lites. The only things you need more of are nail/staple guns and patience. I actually prefer working with the 1/4" and 1/8" ply. It's much easier to cut with the jigsaw, cheaper, and lighter. I find the construction easier as well, because there are only four cuts that are angled. Everything else is cut at an easy 90 degrees.

As far as the build goes, I'm just playing the waiting game now. Bad weather today, and a weekend full of plans. I'll take a picture this afternoon when I knock the throat sheath jig and hopefully have a nice completed horn.

-Nathan

[miked]

I don't see why anyone who can build a regular Jack couldn't build one of the Jack Lites. The only thing you needs more of are nail/staple guns and patience. I actually prefer working with the 1/4" and 1/8" ply. It's much easier to cut with the jigsaw, cheaper, and lighter. I find the construction easier as well, because there are only four cuts that are angled. Everything else is cut at an easy 90 degrees.
-Nathan

That's a very straight-forward and logical statement. Hopefully those looking to build Jacks will see your post and consider the J-lites. BTW: What will you be using these for? PA? Bass guitar?

[ncgrove]

This guy is primarily for bass guitar. I'm going to gut my regular J15 and use the driver and melded array in the Lite. I already have a buyer lined up for the empty cab. I really like the J15 for bass, but I've actually become more interested in DR250s for bass guitar recently.

Anyway, aside from being great for bass guitar duty, the J15 is incredibly versatile. It works really well for outside parties (kind of an overkill for indoors, but easy enough to turn down the volume) and just a little Lepai 12V amp will get it to anti-social volumes. And it'll run all day (at least) on a small SLA battery. When the size of the J15 isn't practical, as in tailgating or beach situations where transport space is limited (Beer gets higher transport priority than tunes), the J10L with about 10 watts still destroys anything else. As far as I can tell, the J15 has about the sensitivity of a J210.

[ncgrove]

Got the horn all cleaned up. Now it's ready for a whole bunch of Bondo and sanding. I'll have to finish assembling the inside braces and driver spacer first. Here's some pictures:

[ncgrove]

I got the back and side braces installed, as well as the duct extension. Everything is different lengths of 2" wide strips, so nothing too difficult. There are just a whole lot of pieces to glue and tack in place. It was a marathon session, but I took my time, and here's what it looks like:



I also got the back panel put together with all of its bracing. I think I'm going to have to chop out one of the braces in order to install a speakon jack mounting plate. I'll figure out a way to reinforce it. The back looks pretty cool with all the bracing:



I'm going to get the back panel mounting strips installed before I start pounding on staples and nail heads. This cab is going to be solid as a rock!

[ncgrove]

Back mounting flanges and driver spacer installed. Almost time for Bondo and sanding!

[DJPhatman]

Nathan, nice build and thread. A quick question: why wait until this point in the build to install the driver spacer to the baffle? Would it not have been easier to install the spacer and test-fit the driver with the baffle not installed in the cab? Also, how thick is the spacer/baffle combo? What driver are you planning on using?

[Bill Fitzmaurice]

A quick question: why wait until this point in the build to install the driver spacer to the baffle? Would it not have been easier to install the spacer and test-fit the driver with the baffle not installed in the cab?

If you do it's difficult to attach the horn braces to the baffle.

[ncgrove]

A quick question: why wait until this point in the build to install the driver spacer to the baffle? Would it not have been easier to install the spacer and test-fit the driver with the baffle not installed in the cab?

If you do it's difficult to attach the horn braces to the baffle.

Yep. Need to shoot some brads through the baffle, into the horn braces. But it was for a bunch of other reasons too. I was using nails to attach the horn panel bending jig to the baffle, and I'm sure the driver spacer would have been mangled in the process. In the assembly of the cab, the driver spacer would be one more thing in the way of the nail gun while fastening pieces. Also, I wasn't sure if there were going to be clearance issues between the driver spacer and duct extensions. I decided I'd rather trim the driver spacer than the duct extensions, and this would be easier with the spacer not glued in.

But I've never installed driver spacers until most of the cab is built (With the exception of the T39). The spacer is a half inch thick, and the baffle is a quarter inch. I also can't test fit the driver (2515) because it's in my Jack 15, which gets used. I won't have the ability to fit the driver until I have a time frame where I can get it going in a day or two. As it is now, I still need to glue in some foam phase plug extensions, pound in staples and nails, Bondo the crap out of the cab and sand it, put in and drill melded array supports, and Duratex. All the while I have rehearsing and a show on the 7th. I doubt I'll get all that done before then. It's easy enough to trim down the driver spacer and phase plug extensions if there's a problem.