Just ordered an OB7 kit and posted some pictures in a gallery

jdbrian · « **on:** 8 Mar 2010, 10:20 pm »

Hi folks

Just ordered ob7's with the woofer upgrade and the norez. Looking forward to the build. I posted a couple pictures of some of my DIY equipment in the gallery. The tube amp is not in my system now but I am going to try it on the 7's as 50w should be enough to play fairly loud on them.

Brian

S Clark · « **Reply #1 on:** 8 Mar 2010, 11:24 pm »

Congratulations.

These should keep you happy for years and years. 50 watts is kind of a perfect match for the OB7's. I remember that Danny was using 50 wpc Dodds when he designed them.

Scott

NeilT · « **Reply #2 on:** 9 Mar 2010, 02:52 am »

Brian, take lots of pictures of the build, I hope to be starting an OB7 build soon.
Thanks
Neil

jdbrian · « **Reply #3 on:** 9 Mar 2010, 04:12 pm »

Quote from: NeilT on 9 Mar 2010, 02:52 am

Brian, take lots of pictures of the build, I hope to be starting an OB7 build soon.
Thanks
Neil

Hi Neil

I plan on documenting it so there should be plenty of pictures. There aren't many examples of building from scratch as most seem to be of flat pack builds.

Brian

Nick77 · « **Reply #4 on:** 9 Mar 2010, 04:34 pm »

Congrats! You will be very happy. I built mine from scratch but didnt take tons of pics.
http://www.audiocircle.com/index.php?topic=53169.msg475079#msg475079

NeilT · « **Reply #5 on:** 17 Mar 2010, 04:57 pm »

Hi Brian, have you started your build yet?
and have you or anybody else thought about grills for the OB7's or OB5's?
Danny, would grills be a bad idea, sound-wise?
Thanks
Neil

jdbrian · « **Reply #6 on:** 18 Mar 2010, 10:28 am »

Hi Neil

My kit hasn't been shipped yet, but yes, I am well under way on the build. I have all the parts cutout, the holes done on the braces etc. I am doing grills as well. I am mounting magnets in the baffles front and back to hold the grills in place. I really don't like the idea of the backs of the drivers(V.C. vents) being open all the time. Due to the built in trim ring on the GR woofers and the round over on the baffle edges it isn't going to be easy to make grills that are strong enough and also don't interfere with the sound but I am going to give it a try. I will likely remove them when listening but I like to keep the sun and dust off the drivers when not in use. I'll post some pictures later. Lee Valley Tools sells the magnets I am using. They come in sets of 4 with a steel cup that the magnet fits into and a steel washer that you attach to the item you want to hold. There are also matching thin rubber pads to keep the washer from scratching the baffle. They have a web site and sell online.

Cheers
Brian

NeilT · « **Reply #7 on:** 18 Mar 2010, 03:01 pm »

That is exactly what I was thinking about doing, grills front and back.
Can't wait to see your pictures.
Neil

Danny Richie · « **Reply #8 on:** 18 Mar 2010, 03:15 pm »

Use these as a guide: http://www.gr-research.com/pdf/grill%20covers.pdf

jdbrian · « **Reply #9 on:** 18 Mar 2010, 03:22 pm »

Hi Danny

Thanks for the info. Do you have an estimate for a shipping date for my kit.

Brian

Danny Richie · « **Reply #10 on:** 18 Mar 2010, 09:32 pm »

Quote

Hi Danny

Thanks for the info. Do you have an estimate for a shipping date for my kit.

Brian

It went out yesterday.

jdbrian · « **Reply #11 on:** 19 Mar 2010, 02:54 pm »

Thanks Danny!

I am not working for the next week so the cabinets should be finished by the time the kit gets here.

Brian

newportcycle · « **Reply #12 on:** 25 Mar 2010, 10:39 pm »

Any updated photos? Hows the build going?

jdbrian · « **Reply #13 on:** 25 Mar 2010, 11:05 pm »

Hi

I have got the baffles nearly finished , veneer on, woofer holes done just need to do the tweeter holes. The bases are finished and ready to paint. The boxes are under construction with the tops, bottoms, d and h braces and back panels glued to a side panel. I have taken pictures but have not been able to get on the computer to download them as my wife is doing a major project and needs the computer all day. I'll post some soon.
I made a few changes in the box , making the base / bottom thicker 1.5" and the crossover mounts in the base which has a cover that is attached with 8 bolts and t nuts making it easy to remove and replace. This allowed me to reduce the baffle height to 48" from 49.5 which means it could be built from the standard 2'x4" panels of MDF. The base has a 3/4" round over as does the baffle which is maple veneer with solid edges. The baffle is 1.25" thick.
It is coming along nicely but it is a lot of work and I am taking my time and assembling the boxes precisely.

Back to work on those baffles

Regards
Brian

NeilT · « **Reply #14 on:** 25 Mar 2010, 11:40 pm »

Sounds great Brian, looking forward to many pictures.
Neil

persisting1 · « **Reply #15 on:** 26 Mar 2010, 10:29 pm »

Quote from: NeilT on 25 Mar 2010, 11:40 pm

Sounds great Brian, looking forward to many pictures.
Neil

+1

jdbrian · « **Reply #16 on:** 27 Mar 2010, 02:15 pm »

Hi Folks

Got the baffles finished - tweeter holes done and 3/8" round over on backs of woofer holes. Boxes are glued up as well. Now I will start on getting them ready to finish.
I'll try to post pictures tomorrow. Today is the MIL's 80th birthday so there is a big party happening.

Brian

jdbrian · « **Reply #17 on:** 28 Mar 2010, 07:06 pm »

Hi

Finally some pictures. I started with 2x4 panels of mdf from Home Depot and cut it on the table saw using the same setup to rip all the parts of a given size. Then I installed a crosscut table and cut all parts to length using a stop block setup for each size. This went a long way towards making all identical parts the exact same size which eases assembly. I divided the project into 3 parts baffle, box and base and wrote down the steps to build them before I started. I had to make some changes and additions along the way but I found these written steps a big help. Here is a picture of the panels and veneer. I then cut the brace holes. If you don't have a good dust collection system do this outside. The dust is incredible. I used a 1/4" spiral bit which does not create as smooth a hole as a conventional bit but cuts easier. I looked at using 1/8" bits with an adapter which cuts dust in half but they flex and bend in thick material so I stuck with 1/4" and did them outside.

jdbrian · « **Reply #18 on:** 28 Mar 2010, 07:20 pm »

Next, I laminated the baffles. I wanted to use solid wood edges and a 3/4 round over. I ended up making the bottom layer 1/2" thick and 71/2 wide and the top layer 3/4" thick and 7" wide and trimmed it back to final size when the veneer was applied. I installed magnet cups and magnets in the baffle front and back to hold grills. I got them at Lee Valley Tools. I used contact cement(2 coats on veneer and baffle) to attach the paper backed maple veneer. I started with the top, then front and the open part of the rear of the baffles as well.

Laminating Baffle

Magnet cups in top rear of baffle

Veneered Baffles

jdbrian · « **Reply #19 on:** 28 Mar 2010, 07:38 pm »

Next step - I started constructing the box. I attached the bottom middle D brace and top then back to the box.I changed the base/bottom design and decided to make the base 1.5" thick. There are 2 layers of 3/4mdf in the base. The top layer has a 5" by 12.25" hole for the crossover. The bottom layer has a hole 6.5" by 13.75" to allow for a cover with a 3/4" lip. The bottom of the box also has a 5" by 12.25" hole for the crossover. So the crossover sits 3/4" below the bottom of the box versus 3/4" above the bottom of the base in the official version. This allowed me to reduce the baffle height to 48" and use the standard 2 by 4ft panels. Pictures below. The bottom cover is rabbited on the top side for the gasket and the bolts holes are countersunk on the bottom so the base will sit flat on the floor.

Gluing a back panel to box

Base parts Left to right bottom layer, top layer with T nuts for cover and box bottom

Left to Right- box cover bottom, top view and gasket.