Jack 12 lite build

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Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Jack 12 lite build

#1 Post by Lustyik »

Hi,

A have started a new project.
After I finished OT12s and T39s (viewtopic.php?f=30&t=24406), I was daring to jump into the adventure of a pair of JL12 building.

It looks amazing and based on the description a pair would be more than enough for our band in many cases. I could use them for garden parties and similar events as well.

I wanted to use a tilt top-hat because OT12 is hanging backwards a bit.
Tilt top hat is bigger than the general tube shaped top hat. I was afraid that larger size would effect the sound. I asked and got valuable advices here: viewtopic.php?f=25&t=25209

Cut it short, here you are some pictures. I will continue the project next weekend.
Attachments
IMG_2021.jpg
IMG_2021.jpg (30.12 KiB) Viewed 1455 times
IMG_2018.jpg
IMG_2018.jpg (27.19 KiB) Viewed 1455 times
IMG_2017 másolat.jpg
IMG_2017 másolat.jpg (28.74 KiB) Viewed 1455 times
IMG_2019.jpg
IMG_2019.jpg (25.54 KiB) Viewed 1455 times
IMG_2020.jpg
IMG_2020.jpg (29.29 KiB) Viewed 1455 times
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Jack 12 lite build

#2 Post by himhimself »

:clap: looking good!
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Re: Jack 12 lite build

#3 Post by Lustyik »

I continued my build last weekend.
To install of sides horn braces was quick and easy. Everything is squared.
Attachments
JL sides top bottom.jpg
JL horn braces.jpg
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Re: Jack 12 lite build

#4 Post by Lustyik »

I was ready to install horn sheets but I made some serious mistake I would like to share.
I decided to fix the horn sheets without brads or staples.
I tried two methods. First I made a “dry” fit, installed the jig screwed to the baffle. Then I apply glue, curved and fixed the sheets with clamps.
Other method was similar but I installed the jigs after the glue was applied to both sides and then I turned the cab face down. I put some weights on top till the pressure was enough.
After the adhesive has cured I checked the joints. Al was wrong. The two ends was OK, but the horn sheets did not achieve the braces in the middle even though “dry” trial was perfect.
So, I would recommend to use staples as it is the first option in the plan. “Clamping” method also in the plan but it is for well experienced builders IMO.
Next weekend I have to clear braces and reassemble the sheets but now with staples.
Attachments
Method no. one
Method no. one
Method no. two
Method no. two
Looks nice...but
Looks nice...but
Adhesive did not touch the sides
Adhesive did not touch the sides
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28620
Joined: Tue May 02, 2006 5:59 pm

Re: Jack 12 lite build

#5 Post by Bill Fitzmaurice »

There's no need to reinstall the panels, just inject adhesive into the space between the braces and panels. It will expand to fill the voids. It's a tight reach to get in there, but you can do it by loading adhesive on to the end of a paddle, like a paint mixing stick. If you want to get fancy get a foot or so length of 1/4 inch ID plastic tubing, fit it over the end of the adhesive nozzle to act as a nozzle extension.

Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Re: Jack 12 lite build

#6 Post by Lustyik »

Thank you Bill!

The "fancy" solution sounds nice. :)
I am going to try it at weekend and I'll share the result.
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

himhimself
Posts: 599
Joined: Fri Nov 13, 2015 9:34 pm
Location: Vancouver BC & Bloomington IN

Re: Jack 12 lite build

#7 Post by himhimself »

I thought I posted a reply but don't see it, so here goes again.
I had a similar issue with my otop jarrays, with a gap between the sheaths and the braces. I just used a glove, put a dollop of pl on my finger and reached in from behind, smoothing it into the gaps. Cured up nice and solid, no hollow sound when knocking on the fronts now. I used clamps for the install, pinning the sheaths to the center braces right next to the baffle to keep them from slipping away when tightening the clamps.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

CoronaOperator
Posts: 1648
Joined: Wed Mar 25, 2009 7:07 pm
Location: Medicine Hat, Alberta, Canada

Re: Jack 12 lite build

#8 Post by CoronaOperator »

To get PL into tight spots look what I did at the bottom of this post: viewtopic.php?p=263287#p263287 (you have to scroll down a bit)

Inject PL into a medicine syringe you get anywhere they sell cough syrup, then you have a mini caulking gun.
Built:
17" width 10" driver Autotuba
2 x 29" width dual Lab12 Tuba60
6 x DR250 2510/asd1001
In progress:
2 x DR250 2510/asd1001
For best results, point the loud end of the array towards the audience

Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Re: Jack 12 lite build

#9 Post by Lustyik »

This weekend I continued my project.
I had two sheets in place but with gaps and I had to reinstall the two others.
I forgot to check my stock and recognised I did not have enough adhesive.
My priority was to finish the assembly of the horn sheets.
Fortunately I found a bottle of PU adhesive on the shelf. PU Max by Bison. It is strong and expands well. For Cab building is not good because it is thin glue with low viscosity, so it is liquid. It does not sit in the place as the PL or KK does.
As it is in a small bottle and liquid I came up with the idea to try it for fixing the joints between the baffle and the horn sheet. It was easy to apply the glue to the untouchable place. The result can be seen on the picture below.
I did not try to fix the gap between the braces and the sheet yet. Thin glue is not adequate for that holes. I will buy more KK glue and use the technic that Bill and Corona operator recommended to me last week.
Attachments
JL PU Max thin glue.jpg
JL PU fix inside.jpg
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Re: Jack 12 lite build

#10 Post by Lustyik »

Finally I started my major project of the weekend. I investigated what was wrong at first time.
My findings are:
- Proper amount of adhesive was not apply to the braces;
- The adhesive that I used has to be applied within 3 minutes but two sides assembly took more time. So one side once, do not rush.
- I forgot to use a damp cloth to moisten the side to which no adhesive was applied.
- Too big pressure on the horn sheets deformed the curve and the horn sheets moves away from the braces.
I added some “extra” scrap wood to reinforce the joint between the horn sheets and the Baffle. First I applied adhesive only to the joint of the baffle and sheet, than inserted the sheet and clamped the scrap jig. Tis time I was able to check the connection between the inner side of the sheet to the baffle and to the beginning of the braces. When all was in the right position I applied glue to the rest and turned the cab face down on the edge of a table so that the end of the horn sheet was over the edge. I gradually pushed the cab from the edge of the table to the middle. I could see from the back how the sheet curved to the braces.
When all joints looked nice I put some weight onto the top of the cab.
This way I could see and check the joints in the inner side of the sheet.
Attachments
JL 1.jpg
JL 2.jpg
JL 3.jpg
JL 4.jpg
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28620
Joined: Tue May 02, 2006 5:59 pm

Re: Jack 12 lite build

#11 Post by Bill Fitzmaurice »

To make sure I had enough adhesive on the bent panel joints I first dry fit them, tracing the joints onto the inside of the panels with a pencil. When I applied the adhesive I put it on the braces and on the panels where the joints were marked.

Lustyik
Posts: 76
Joined: Sat Sep 28, 2013 10:54 am
Location: Hungary

Re: Jack 12 lite build

#12 Post by Lustyik »

I forgot to mention that step in my description. I marked the inner side of the panels as well during the dry fit. After than I put adhesive to the marked parts too. I did not have time to take pictures as I had to rush during the process. This method works properly.

Thank you again for your support!

Hope weekend comes quickly and I can repair the rest of the braces via yours "plastic tube" technic. :)
Built: 2x OT12 (2512; NSD)
Ongoing: 2x T39 (3012)


PreSonus sl 16.4.2
Driverack PA
Driverack PX
PKN XD2500 (2x650w / 8ohm)
PKN LC4004 (4x500w / 8ohm)

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