Otop 8 future build

High power and fidelity from an easy to build cabinet.
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Seth
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Re: Otop 8 future build

#31 Post by Seth » Sat Nov 27, 2021 11:57 am

2K_ASD_Comp.jpg
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

kenkenni
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Joined: Mon Apr 30, 2012 6:34 pm
Location: Atlanta, Ga

Re: Otop 8 future build

#32 Post by kenkenni » Sat Nov 27, 2021 5:01 pm

Man. Now I get it. Thanks for the detail sketches. I would have probably never figured it out.

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Seth
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Re: Otop 8 future build

#33 Post by Seth » Sun Nov 28, 2021 3:21 pm

It took some concentration for me to figure it out too. The extra cap was the first head scratcher. I assume they're 4 Ohm crossovers and the 20uF cap value was achieved by combining caps of smaller values (the two on the right) in parallel. Then it was just a matter of figuring out how the coils were routed. More than a few minutes passed before I connected all the dots, so don't don't get down on yourself for not seeing it too.

I'm looking forward to future updates on this project :thumbsup:
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

kenkenni
Posts: 203
Joined: Mon Apr 30, 2012 6:34 pm
Location: Atlanta, Ga

Re: Otop 8 future build

#34 Post by kenkenni » Tue Nov 30, 2021 8:43 am

Will have updates and pics soon. Thanks again for the info.

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LelandCrooks
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Re: Otop 8 future build

#35 Post by LelandCrooks » Wed Dec 08, 2021 9:38 am

Sorry, I usually label on the back of the boards what goes where.
If it's too loud, you're even older than me! Like me.
http://www.speakerhardware.com

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Chris_Allen
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Location: Huddersfield, UK

Re: Otop 8 future build

#36 Post by Chris_Allen » Thu Dec 23, 2021 9:28 am

LelandCrooks wrote:
Mon Nov 22, 2021 10:33 am
Getting pretty good at Otop 8's, they're popular. It's a pretty fun cab to build too.
I'm still wanting to build a pair and compare them to the SLAs.
Built:
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10

kenkenni
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Location: Atlanta, Ga

Re: Otop 8 future build

#37 Post by kenkenni » Mon Jan 10, 2022 1:23 pm

Is there a standard bolt size that I need to install the compression drivers? I have the bolt-on versions not the screw-on adapter versions. I also just noticed I don't have
holes cut for the top hats. Looking at the SketchUp model it looks like two holes have to be cut. One in bottom of cab and one through the reflector. Can someone offer
advice as to how to properly cut the hole in reflector. Remember my cabs came pre-assembled. I do not have a drill press so I am going to have to tackle manually.

Bruce Weldy
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Location: New Braunfels, TX

Re: Otop 8 future build

#38 Post by Bruce Weldy » Mon Jan 10, 2022 3:12 pm

kenkenni wrote:
Mon Jan 10, 2022 1:23 pm
Is there a standard bolt size that I need to install the compression drivers? I have the bolt-on versions not the screw-on adapter versions.
According to the spec sheet on the ASD1001B

MOUNTING INFORMATION
Overall Diameter 3.5", 88.9mm
Driver Volume Displaced 0.009 cu.ft., 0.26 liters
Depth 2", 50.8mm
Weight 1.7 lbs, 0.8 kg
Mounting Thread N/A
Mounting Holes Diameter 2X M6
Mounting Holes B.C.D. 3 in. 76.2 mm

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

kenkenni
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Joined: Mon Apr 30, 2012 6:34 pm
Location: Atlanta, Ga

Re: Otop 8 future build

#39 Post by kenkenni » Mon Jan 10, 2022 3:32 pm

Thanks bruce. I believe I got some bolts laying around in the proper size. Gonna give it a try

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Bill Fitzmaurice
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Re: Otop 8 future build

#40 Post by Bill Fitzmaurice » Mon Jan 10, 2022 4:26 pm

I don't recall the size, but when I've bought bolt on drivers they came with bolts.

kenkenni
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Location: Atlanta, Ga

Re: Otop 8 future build

#41 Post by kenkenni » Mon Jan 10, 2022 4:29 pm

I looked into the packages on mines, but no bolts. Might need to just break out the tape measure.

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Tom Smit
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Re: Otop 8 future build

#42 Post by Tom Smit » Mon Jan 10, 2022 4:53 pm

I had to install top hats after the OT12s cabs were built. I measured from the front edge of the cab to were the reflector meets the baffle (put a board across the front to measure against). I took that measurement and found the baffle location on the outside of the cab, on top and bottom. Measuring across, I found centre. Using the right-sized hole saw (with pilot bit removed) I drew the circle on the forward edge of the baffle line, and then found the centre of that circle and centre-punched it. I carefully drilled down through both the panel and reflector. Oh, about the reflector. I put painters tape, where the hole was going to be, to prevent tear out. Also, to make sure that you are drilling square, cut out a perfect square notch out of a 2x4 chunk, and put the bit equal to, and touching both sides of that notch. Similar to this..... https://www.bobvila.com/articles/how-to ... ight-hole/
TomS

Bruce Weldy
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Re: Otop 8 future build

#43 Post by Bruce Weldy » Mon Jan 10, 2022 5:09 pm

kenkenni wrote:
Mon Jan 10, 2022 3:32 pm
Thanks bruce. I believe I got some bolts laying around in the proper size. Gonna give it a try
Or, just go to Home Depot and get some M6 bolts to be sure...don't want to cross-thread 'em. Take the driver with you to be sure...and get a washer and lock washer for each bolt.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

kenkenni
Posts: 203
Joined: Mon Apr 30, 2012 6:34 pm
Location: Atlanta, Ga

Re: Otop 8 future build

#44 Post by kenkenni » Mon Jan 10, 2022 7:26 pm

So I went to Home Depot and picked up a pack of M6-1.0 X 25MM screws and a pack of M6 washers. Perfect fit. Thanks Bruce

kenkenni
Posts: 203
Joined: Mon Apr 30, 2012 6:34 pm
Location: Atlanta, Ga

Re: Otop 8 future build

#45 Post by kenkenni » Tue Jan 11, 2022 1:39 pm

Tom what would you recommend for the top hat depth. On my SLAs I have a 1-1.2" top hat for a 1-1.2" top hat stand.
The depth of the stalk is 4.5". Do I want 4.5" or for Otop 8 should I get the 3" deep stalk?

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