X-over layout *PIC*

[Mr.Thomas Aaron Hero]

I just finished a pair of xovers for my new speaks and used Erse Super Q I core inductors to save some money,anyway does this arangment look okay as far as spacing and orientation go?
I can believe the cost of Xover components! I wish there was a way to use an active crossovers without using three amp on a three way speaker!

A.H.

[Wolf]

> I just finished a pair of xovers for my new
> speaks and used Erse Super Q I core
> inductors to save some money,anyway does
> this arangment look okay as far as spacing
> and orientation go?
> I can believe the cost of Xover components!
> I wish there was a way to use an active
> crossovers without using three amp on a
> three way speaker!

Looks okay to me! I like the looks too!
Wolf
> A.H.

[bill]

> I just finished a pair of xovers for my new
> speaks and used Erse Super Q I core
> inductors to save some money,anyway does
> this arangment look okay as far as spacing
> and orientation go?
> I can believe the cost of Xover components!
> I wish there was a way to use an active
> crossovers without using three amp on a
> three way speaker!

> A.H.

Aaron,

You will definitely have crosstalk between the two Erse inductors and the small coil on the larger board, and you will likely have problems on the smaller board as well. You need more space. You should also plan on more separation between boards.

When laying our crossovers, I connect the coils in series and to an LC meter. I then move the coils around until the total inductance drops to the sum of the individual inductances. When doung this, you have to flip the coils end for end to ensurte that you're not fooling yourself because you're combining in-phase and out-of-phase interactions.

HTH,
Bill

[Wolf]

> Aaron,

> You will definitely have crosstalk between
> the two Erse inductors and the small coil on
> the larger board, and you will likely have
> problems on the smaller board as well. You
> need more space. You should also plan on
> more separation between boards.

> When laying our crossovers, I connect the
> coils in series and to an LC meter. I then
> move the coils around until the total
> inductance drops to the sum of the
> individual inductances. When doung this, you
> have to flip the coils end for end to
> ensurte that you're not fooling yourself
> because you're combining in-phase and
> out-of-phase interactions.

I may have to do that when I layout mine then. I've not used the ERSE, as I normally use air-core Jantzens, Solens, or Sidewinder. I didn't know how strongly they would couple. I would have stood one of the air-cores on the smaller board on-edge personally. I learned something!
Later,
Wolf

[Chris Roemer]

> Aaron,

> You will definitely have crosstalk between
> the two Erse inductors and the small coil on
> the larger board, and you will likely have
> problems on the smaller board as well. You
> need more space. You should also plan on
> more separation between boards.

> When laying our crossovers, I connect the
> coils in series and to an LC meter. I then
> move the coils around until the total
> inductance drops to the sum of the
> individual inductances. When doung this, you
> have to flip the coils end for end to
> ensurte that you're not fooling yourself
> because you're combining in-phase and
> out-of-phase interactions.

> HTH,
> Bill

All looks very nice, but . . .

in general, if you imagine that the coils are like gears turning on axles, and if you've got two of them arranged so that they could "mesh" with and turn each other, then they'll interact (causing their inductances to NOT be what they're marked, they can go up OR down). The two little gears (coils) on the small board look like they'll mesh pretty well (bad). I'd prefer to stand one of them up on edge, that would be OK.

The 2 iron cores are probably also a problem given their orientation unless they're at least 4 or 5 inches apart. Hard to tell. Also, it's like a sub next to a CRT, the bigger, the more (adverse) effect it can have.

They look real nice, though.

[Mr.Thomas Aaron Hero]

Thanks all, The two I core have a 4.5" space between (far enough?)The coils on the second board will be 6" away from the main board when mounted in the cabinet.

I do have another question as well,after all components are wired,some dont read the same value as they did before connected,for instance some caps measure + or - their rated value after connected when measured at their individual leads, (where the lead leaves the body of the cap) Is this common or is there a problem somewhere? Thanks! A.H.

[Mr.Thomas Aaron Hero]

As I mounted the erse coils to the board I checked them with my LC meter and the values stayed the same as their rated value, would this mean that they will be okay or will this change once power is added to them?
As a matter of fact I measured all the coils after they were mounted and they all kept their value.

I don't know if this is the proper way of checking for interferance between the coils so if I am wrong please let me know. Thanks again! A.H.

[Paul K.]

On the smaller board, if the two air-core coils are 2 inches or more apart (as measured between their outer diameters), the "crosstalk" between them will be less than -50 dB, completely inaudible.
Paul K.

> Thanks all, The two I core have a 4.5"
> space between (far enough?)The coils on the
> second board will be 6" away from the
> main board when mounted in the cabinet.

> I do have another question as well,after all
> components are wired,some dont read the same
> value as they did before connected,for
> instance some caps measure + or - their
> rated value after connected when measured at
> their individual leads, (where the lead
> leaves the body of the cap) Is this common
> or is there a problem somewhere? Thanks!
> A.H.

[Paul K.]

At least on air cores, you won't measure any changes due to the proximity of other air core coils unless there is current going through one of them, and I doubt the current from a typical DMM will "excite" the coils very much.
Paul K.

> As I mounted the erse coils to the board I
> checked them with my LC meter and the values
> stayed the same as their rated value, would
> this mean that they will be okay or will
> this change once power is added to them?
> As a matter of fact I measured all the coils
> after they were mounted and they all kept
> their value.

> I don't know if this is the proper way of
> checking for interferance between the coils
> so if I am wrong please let me know. Thanks
> again! A.H.

[bill]

> As I mounted the erse coils to the board I
> checked them with my LC meter and the values
> stayed the same as their rated value, would
> this mean that they will be okay or will
> this change once power is added to them?
> As a matter of fact I measured all the coils
> after they were mounted and they all kept
> their value.

> I don't know if this is the proper way of
> checking for interferance between the coils
> so if I am wrong please let me know. Thanks
> again! A.H.

You won't see any appreciable effect by measuring one coil at a time. To see the interactions, you have to drive both coils at the same time. The technique I described will pick up the interactions, registering them as changes in total inductance. The effect on the actual circuit will be different; what you'll get is currents flowing where they don't belong, as if you had a lossy transformer instead of two or three separate inductors. That's a much worse problem than a simple shift in inductance value.

I can practically guarantee you that if you connect those two Erse inductors in series, what you'll read on an LC meter will be either higher or lower than the sum of the two. The small air-core is OK as far as orientation, since it's perpendicular to the winding axis of the other two inductors, but it's so close to them that I'd expect to see an increase in inductance due to the ends of the iron cores being in its magnetic field.

Best regards,
Bill

[bill]

> Thanks all, The two I core have a 4.5"
> space between (far enough?)The coils on the
> second board will be 6" away from the
> main board when mounted in the cabinet.

> I do have another question as well,after all
> components are wired,some dont read the same
> value as they did before connected,for
> instance some caps measure + or - their
> rated value after connected when measured at
> their individual leads, (where the lead
> leaves the body of the cap) Is this common
> or is there a problem somewhere? Thanks!
> A.H.

Once all the parts are soldered together, you won't be able to get an accurate reading of their values. You'll have all kinds of sneak paths through the other components.

6 inches is kinda close. 8 would be better.

HTH,
Bill

[Mr.Thomas Aaron Hero]