Otop 8 future build

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kenkenni
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Location: Atlanta, Ga

Re: Otop 8 future build

#46 Post by kenkenni »

Okay I am almost done with the wiring part of the first Otop 8. I am following the diagram that Seth drew up
for me above. I believe I have those connected properly. I am at a mini-stop as I believe I know what I need to
do but I need to confirm with you guys first. I see in Seth's diagram where one set of the wires to the amp get
connected. Am I correct in thinking that the remaining pair of wires get connected as so: The remaining positive
wire gets connected near the upper-mid right of the diagram near the two zip-tied capacitors and the left over
positive is connected near the bottom using the spare positive terminal to the left of the inked line. Thanks for
any help you guys are able to provide.

Here is the stage I am at on the first one:

Image

Please point out any issues you might recognize and as always any advice is appreciated.

Also remember you can right-click and open in new tab for full-res image. Thanks

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Seth
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Re: Otop 8 future build

#47 Post by Seth »

You only need one pair off the back of the terminal cup which go to the crossover. Cut one pair off.
IMG-0167.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

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Seth
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Re: Otop 8 future build

#48 Post by Seth »

Also, it looks like you have the drivers wired in series for a 16ohm cab. Are the component values in your crossover also for 16ohm wiring?

I initially thought they were 4 ohm crossovers due to the paralleled capacitors on the Highpass portion of the crossover circuit. But, it was only an assumption. Can you tell me the value on the capacitor circled below?
IMG-0167.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
Posts: 203
Joined: Mon Apr 30, 2012 6:34 pm
Location: Atlanta, Ga

Re: Otop 8 future build

#49 Post by kenkenni »

Seth it's a 33uF 100v

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Seth
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Re: Otop 8 future build

#50 Post by Seth »

Seth wrote: Tue Jan 11, 2022 7:27 pm You only need one pair off the back of the terminal cup which go to the crossover. Cut one pair off.

IMG-0167.jpg
OR run the extra pair up to your 1/4" jacks
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

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Seth
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Re: Otop 8 future build

#51 Post by Seth »

kenkenni wrote: Tue Jan 11, 2022 7:47 pm Seth it's a 33uF 100v
Yeah, that's the 4ohm crossover. You want to wire the woofers parallel as shown on page 25 of your plans.
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

#52 Post by kenkenni »

Okay I am looking over page 25 and 26 of the plans again to get a better understanding. As far as my connections and when I remove the extra set
of cables to the speakon cup will I stll be able to pass-through a sub. I decided to leave the 1/4" connections un-attached at this time as I decided
to keep it simple, but if you say I can run the extra pair to the 1/4" connections I might just go ahead and connect them. Am I running the +/- wire
to just one side of the 1/4" connectors and leaving one unused?

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Seth
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Re: Otop 8 future build

#53 Post by Seth »

kenkenni wrote: Tue Jan 11, 2022 8:07 pm Okay I am looking over page 25 and 26 of the plans again to get a better understanding. As far as my connections and when I remove the extra set
of cables to the speakon cup will I stll be able to pass-through a sub.
I can't say 100% without being able to read the markings on the SpeakOn jack, but if you're wiring them per the plans, the leads you have coming off are connected to terminals 2 positive and 2 negative on the back of the SpeakOn. The two that just jump across without any leads coming off are the pass through siganal and should be connected to 1 positive and 1 negative.
IMG-0167 (2).jpg
Yes, the sub signal will still pass through.

The reason you have two extra leads is, in the plans the two crossovers (one for the tweeters, one for the woofers) are made on separate boards and the two sets of leads would go one to each crossover. But, the crossover you got from Leland has both crossovers on one board, so it only needs one input from one set of leads. You did a great job wiring your terminal cup exactly as the plans show, you just only need the one pair in this situation though. Which may ultimately work out well for you...
I decided to leave the 1/4" connections un-attached at this time as I decided
to keep it simple, but if you say I can run the extra pair to the 1/4" connections I might just go ahead and connect them. Am I running the +/- wire
to just one side of the 1/4" connectors and leaving one unused?
Run the positive to the "tip" terminal on one of the 1/4" jacks and jumper over to the tip terminal of the other 1/4" jack. Then run the negative to the "sleeve" terminal of one and jumper to the sleeve terminal of the other. If it's unclear which terminal is which, the one closer to the metal mounting cup is the "sleeve" terminal and the one furthest from it is the "tip" terminal.
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

#54 Post by kenkenni »

Okay here is the speakers re-wired in parallel. I believe I did it correctly this time.
I did both the compression drivers and woofers this way.

Image
Last edited by kenkenni on Tue Jan 11, 2022 9:56 pm, edited 1 time in total.

kenkenni
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Location: Atlanta, Ga

Re: Otop 8 future build

#55 Post by kenkenni »

And here is an image of the cleaned up wiring. On the plate as your looking at it it is in the
same orientation as in the plans with the 1+ terminals at the top.

Image

kenkenni
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Location: Atlanta, Ga

Re: Otop 8 future build

#56 Post by kenkenni »

Seth is this correct for the 1/4" jacks connection.

Image

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Seth
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Re: Otop 8 future build

#57 Post by Seth »

kenkenni wrote: Tue Jan 11, 2022 10:37 pm Seth is this correct for the 1/4" jacks connection.
Sure is. Well done. :thumbsup:

You're nearly ready to fire those bad boys up!
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

#58 Post by kenkenni »

Can't wait. I hope to finish the other one up in much less time. The first one for me is always the hardest.

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

Re: Otop 8 future build

#59 Post by kenkenni »

Ran into a couple of bumps. Finished wiring up the cup but could not install the back properly because of the way
the spade connectors hit the back of the subwoofer. Now I see why in the Sketchup model the cups appear mounted
sideways. Since mines were pre-built I didn't think much of it. So I re-did all the wiring on the cups to just plain wires
and now it closes properly.

Did a sound test, and though I am getting sound from both the subs and compression drivers. The box sounds to me a bit
under-powered. The horns sound good but the two 8" drivers don't seem to put out bass you can feel. Now when I use the
box in conjunction with a subwoofer they shine. Sort of like how the SLAs sound when you run them with a good sub. It is
more of a fuller sound. Mind you, this is just a test run off of my amp which is connected to the Driverack, so I just need
to reset my amp which is a Crown XLS 2502 and run a new setup with the Driverack. And try again. I am not giving up just
yet, but surely two 8s in a box this size should sound more substantial. Not knocking the design or anything like that. Just
trying to do a bit of trouble-shooting and see if I need to re-visit any wiring situations.

I was hoping to finish both boxes while I am on vacation, but I am going to get the first box right first then jump on the second.

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Bill Fitzmaurice
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Re: Otop 8 future build

#60 Post by Bill Fitzmaurice »

kenkenni wrote: Thu Jan 13, 2022 1:24 pm the two 8" drivers don't seem to put out bass you can feel. .
They're not supposed to.
Image

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