N1600 crossovers for my 604Ds

[aditya]

Alan.......some posts back you had mentioned about an inductor calculator from a 'shavano music'. Pls stick to that. It will do very good for you. Your present coil designs, particularly the 2nd one, is an extreme design. Just try to visualize....a coil diameter of 4.17 inches, and thickness (length in your description) of 0.4 inches ! It will be looking like a metal washer.

If you want to be extremely precise, and you have the provisions for inductance measurements, then just wind a bit more (around 5%) and adjust. This you will need for the first one only as you will get the hang of it for the rest.

Cheers

[alancohen]

I see why you want to roll your own. The only one I see in the book close to what you want is 4.7 DCR .60 ohm and 96 bucks a piece!!! PN# 255-698

Yeah, anything with low resistance is big bucks. As Don recommends, I want to try and stay around .5 for the 4.7.

I'm only using a 1.5 W/ch channel amplifier on these, and any voltage drop across the inductors is that much less that the drivers will see. I am guessing that this low DCR is what makes a good crossover from a so-so one

[alancohen]

Alan.......some posts back you had mentioned about an inductor calculator from a 'shavano music'. Pls stick to that. It will do very good for you. Your present coil designs, particularly the 2nd one, is an extreme design. Just try to visualize....a coil diameter of 4.17 inches, and thickness (length in your description) of 0.4 inches ! It will be looking like a metal washer.

If you want to be extremely precise, and you have the provisions for inductance measurements, then just wind a bit more (around 5%) and adjust. This you will need for the first one only as you will get the hang of it for the rest.

I do have a True RMS MM so I can measure inductance and surely will before I install them.

As far as the configuration, I agree, the flat one would look awkward, but the numbers are there. The Shavano "calculator" just gives one configuration:

15 0.69 Ohms 1.05 Inches
( 26.69 mm) 2.10 Inches (radius)
( 53.38 mm) 175 0.059 Inches
( 1.49 mm) 450 Watts 216.8 feet
( 66.1 m)

The DCR is too high and it's still a +4" wafer using 70% more wire. Shavano Music Online - Cross-Over Network; Air Core Inductor Calculator

[aditya]

I do have a True RMS MM so I can measure inductance and surely will before I install them.

As far as the configuration, I agree, the flat one would look awkward, but the numbers are there. The Shavano "calculator" just gives one configuration:

15 0.69 Ohms 1.05 Inches
( 26.69 mm) 2.10 Inches (radius)
( 53.38 mm) 175 0.059 Inches
( 1.49 mm) 450 Watts 216.8 feet
( 66.1 m)

The DCR is too high and it's still a +4" wafer using 70% more wire. Shavano Music Online - Cross-Over Network; Air Core Inductor Calculator

Yes, this is the link that I was talking about.

The first thing about a good inductor (as Don also has mentioned earlier) is that .......its winding area should be of a square cross section, which actually is the best AFA low resistance & accuracy is concerned, and the shavano-thing just does that. Actually it just needs a simple equation to calculate any coil's inductance, but it takes some extra calculations to end it up with a square cross-section. Also pls don't forget the fact that good inductors, like good output transformers, are always bulkier & heavier. Just put 4.7(mH) in the (shavano) box, and go for the prescribed values. As I check them, I think they will hit the bull's eye with the prescribed values.

Goodwishes
Aditya

[Alien_Shore]

I'm no expert at winding coils - only done a few, but I can vouch for the uncanny accuracy of the Shivano calculator code. The boys over there did some good math.

[alancohen]

I'm no expert at winding coils - only done a few, but I can vouch for the uncanny accuracy of the Shivano calculator code. The boys over there did some good math.

I can appreciate that, but it's just not making any sense. If you go to the main page Shavano Music Online - Cross-Over Network; Air Core Inductor Calculator and look at the picture. They're claiming the "radius" is half the core size. So far so good. Then you input 4.7mH and in the table for 15 AWG wire it gives a value for the radius of 2.1". That's a 4.2" core!! That's a 6" OD inductor. That can't be right. Or at least it's not making a very cost effective inductor. And the DCR is .69 Ohms. That's no good either.

[cradeldorf]

Yeah, anything with low resistance is big bucks. As Don recommends, I want to try and stay around .5 for the 4.7.

I'm only using a 1.5 W/ch channel amplifier on these, and any voltage drop across the inductors is that much less that the drivers will see. I am guessing that this low DCR is what makes a good crossover from a so-so one

I know, I hate resistors in any part of my chain. Sorry but they just don't sound natural to me when there's one in the chain.

- - - Updated - - -

I can appreciate that, but it's just not making any sense. If you go to the main page Shavano Music Online - Cross-Over Network; Air Core Inductor Calculator and look at the picture. They're claiming the "radius" is half the core size. So far so good. Then you input 4.7mH and in the table for 15 AWG wire it gives a value for the radius of 2.1". That's a 4.2" core!! That's a 6" OD inductor. That can't be right. Or at least it's not making a very cost effective inductor. And the DCR is .69 Ohms. That's no good either.

Hmm yep that a big inductor, why wouldn't you go with the 13 gauge wire since is is much more closer to .5 dcr? (never mind, I see it's even larger)
I would consider looking for iron core to save money. Especially if your trying to reduce resistance. The Erse super Q's are around .2 DCR for a 4.7Mh 16 gauge and .16 for 14 gauge. And at 18-22 bucks much more economical.

http://www.erseaudio.com/Products/SuperQCoilsAll

Also check these baby's out, this place makes it sound like the lower the DCR the better...

http://www.northcreekmusic.com/COILS.html

[alancohen]

Those Super Qs look interesting. I'll keep them in mind if I do a crossover for the A7s. For this one, I already have 10# of 15 AWG copper on route. I want to try winding my own. I can't tell you why

[alancohen]

Inductor winding party at Alan's house this weekend. Whoo hoo!

[alancohen]

So the back of my 604 cabs have a 5" x 10" cutout.



I figure I'll build the XO on a 5 x 10 ply panel and mount it in the hole. Here's the layout I have so far for the components...