OmniTop12 Crossover setup

[mister2walker]

I noticed that the recommended build for a cross-over in these plans/from Leland is a piece of 1/4" ply and to glue the thing to the side of the cabinet.

I used the following to build the crossover and I would highly recommend it. It doesn't really take any more technical capability but produces a more professional and potentially fire-resistant setup:

2 - 3x5 Radio Shack project breadboards
10 - #8 panhead screws with nuts
2 - 1/2" scrap ply pieces cut in an X pattern
1 pack of electrical connectors for auto connections (flat male and female connects) You can get them in the auto section at walmart in the electrical stuff.

Use a #8 drillbit or slightly larger to open the breadboard holes up just a little more than stock.

Use some PL to glue the inductors to the breadboard.

Try it. It works...

Mark

[Tom Smit]

Cool!
Do you have anymore pics...top view? And how do the terminals stay on the board? And, do you PL the X to the cab panel? Thanks.

[sine143]

Looks a hell of a lot better than mine! one thing though, i had read somewhere on this board (dont remember where) that you were supposed to orient the orient the 2 inductors in different planes, as in, one coming out of the board. cut down on magnetic interference or something?

[Harley]

Cool!
Do you have anymore pics...top view?

+1 ...and some pics from underneath too would help.

[LelandCrooks]

With my prebuilts I'm now supplying nylon spacers and the screws. I guess I should start offering the circuit boards by themselves.

[mister2walker]

Sorry for the delay. Been busy with getting kids graduated from school.

I included two other views of the crossover. For the connectors, I clipped a small section of bare copper wire, soldered it through the breadboard, and then soldered the connector over it as close on the board as possible to prevent having a connector with a lot of lateral weakness.

As for the comment on the coils and positioning them at opposing angles, I didn't see it in the spec but the idea makes sense. It may be an issue for me in this build. I'll double check.

Mark

[sine143]

yah, its not mentioned in the specs. I just remember seeing pictures of some oriented that way. I *think* someone said it cuts the distance between coils from a minimum of like 8" to 4" or something.

Regardless, they look way better than mine!

[mister2walker]

So I cut the PL from between the High-pass coil and the breadboard, lifted it up to a 90deg position and fastened them back down.

Of course, when cutting them off, I scraped the side of one of the coils pretty good, exposing the copper on several wires.

Anyone have a good simple test for an inductor coil to see if the mH value has changed due to a short between wires in the coil? I'm only going to do surgery on that coil if it's actually changed in value.

Mark

[mister2walker]

Cool!
Do you have anymore pics...top view? And how do the terminals stay on the board? And, do you PL the X to the cab panel? Thanks.

Re: Fastening the X board to the inside of the cabinet, I haven't done that yet. But my thought was to screw them in, possibly with a drop of PL near the screw head to keep them from turning by vibration. That way if I ever needed to extract the CO to work on it, I could get it back out.

[mister2walker]

Cool!
Do you have anymore pics...top view?

+1 ...and some pics from underneath too would help.

Harley,
I put the screws on and got the CO's ready to install when I was writing this so I can't get a good shot under the board.

The radio shack project boards have solder points at each hole, but no etched copper between holes. So when I put the leads from the caps, coils, resistors through the board, I solder them to the board and then keep enough leads to bridge between the components. Where I need to go across the board (such as where you see the black and red wires), I use that to make the necessary connections to follow the BFM crossover design. I probably could have reviewed the real-estate and oriented to avoid wires but it really didn't seem to be of much more value to do that level of optimization.

[buggers]

Yes you should always try to space the inductors 20 centimeters apart and turn one inductor on its side...If possible.
http://www.troelsgravesen.dk/coils.htm