N1600 crossovers for my 604Ds

I'm sure this has been discussed ad infinitum. I did a search and tried weeding through all the posts, but couldn't really distille the info down to the lastest and greatest.

I'm planning on dissecting the N1600s that came with the 604Ds. Apparently they are the same model number, but the chassis are a different size. I will likely want to replace the 16uF caps and pots if they look original. I don't think there is much else in there that might need attention.

I found this:

http://www.hostboard.com/forums/hbmc...2013/03/13.jpg

Is this the schematic I should be working from, or is there a better option?

I don't have a clue. I wish you the best with whatever you do though. :) The last D's I saw had accordion surrounds, I would think they would be closer to an "E" than a "C" in character but I have no knowledge to back that up.

Alan

This was drawn from the original N 1600 C that came with my 605A's . I am not really positive of the iron core 1 mH coil value.
The air core 1.4 mH with a parallel 15 Ohm resistor produce the same freq resp curves.
I think you will be OK with this Clone , or if you have the original XOs replace the 16 uF caps.
If you need +2 dB at 10kHz add a parallel 2 uF cap in parallel with the 5 ohm resistor to lift the highs.

Don

www.donpatten.com

Thanks CD and Don. As far as I can glean, the 604D is identical to the 604C. I found this page:

Altec 604's - the various models

Where it says:

Altec 604D (looked just like 604C)
HF horn: 90h40v
X-over: 1600 Hz
Power: 35 watts, 50 peak
Impedance: 16 ohms
Weight: 40 lb.
Magnet: Alnico
Response: 30Hz - 22kHz
Free Air Resonance:
Frame: green hammer-tone
Cone: all paper cone
comment: 604D was in the 1957 catalog and was not superceded by the 605 until 1959
after that 604Ds were built one-off for special customers i.e. recording studios

I have read this same info elsewhere.

I have seen Jeffs XOs for 604Bs w/E cones as well as 8Gs, but nothing for the 604C. I like the idea of a little time delay.

To add to the confusion, mine were reconed by GPA. I guess I should call Bill and see what he might have put in there and what he would suggest. He's got XOs but they're $178/ea. I think I could come in at half that if I build my own.

Here's a pic of the cones on mine:

http://www.hostboard.com/forums/hbmc...2013/03/14.jpg

It may look the same but that surround is gonna be way different. I just pushed on my E cone the other day and it moved very easily, barely any pressure made it move. Then I did the same thing to one of my C's it wouldn't barely budge. Personally If it was me I'd shoot for an E crossover alignment ala N1500. But that's just how I roll.

Maybe I'll use Jeff's 604B w/E cone time delay w/EQ comp one:

http://www.hostboard.com/forums/hbmc...2013/03/16.jpg

And here some better pics of the babies...

http://www.hostboard.com/forums/hbmc...2013/03/17.jpg

http://www.hostboard.com/forums/hbmc...2013/03/18.jpg

These are the XOs that came with the drivers. They're N1600Bs. I opened one up. It's a little nasty in there. A big hunk of tar takes up 1/4 of the chassis. I screwed the back back on and will have these on eBay ASAP. I can't imagine they're any good.

http://www.hostboard.com/forums/hbmc...2013/03/19.jpg

And here is the GPA cone # if that means anything to anyone:

http://www.hostboard.com/forums/hbmc...2013/03/20.jpg

I'd recommend that you measure them, and build a XO...
Don's site is a wealth of info, and he's very generous with his advice as well. He helped me a ton with my 604E.

Quote:

---

Originally Posted by Alien_Shore

I'd recommend that you measure them, and build a XO...
Don's site is a wealth of info, and he's very generous with his advice as well. He helped me a ton with my 604E.

---

I measured them...they're both 15"...

...and weigh a ton. :o


DCR on the LF drivers is exactly 11.0 and the HF drivers are 8.0 and 8.1.

The alchemy of XO design is fascinating to me. If I didn't have so many other things tugging at my coattails, I could see myself getting lost in it learning as much as I could about it.

I'll say this. Once you get those baby's all set your gonna be very happy. Wish I was of more assistance but I've only had the opportunity to play with the half roll surround sound of my C's. I'll say that when I first got my setup and one was a C and one was an E they were worlds apart on their sound. I thought there was something wrong with the E. It was an extremely costly mistake to send them to GPA to have them looked at as they came back sounding the same. I told Bill the E didn't sound as good as the C and thought it needed a phragm. I found the new phragm in the C when I looked. It wasn't the phragm at all because before I sent them I could turn the attenuator in the E's crossover and hear it changing. Between one running a N1500 and the other running an N1600 plus one being an accordion surround and one being a half roll surround there was a definite difference in sound.

Alancohen

I recommend you change the 16 uF cap in each N-1600 . Then if you do build new XOs you will have a base line to compare to.
The old caps are in cardboard boxes with a pair of wires coming out. Cut these wires very close to the box and splice them to the new 16 caps.
Dig out the old caps to make room for the new ones. If the new 16s are tight, or too large, sub two 8 uF caps in parallel . If you want to repot the XOs you could use candle wax.

Don

Don: thanks for the suggestion, but I think I'd rather not bother with these XOs at all. The small one has the L-pad shaft snapped clean off and it just seams like too much trouble when making a new one is relatively easy.

On the subject of making new ones I started doing a little homework and getting my big toe wet in the huge learning curve pool. I have a question. In looking at JM's work with his 604B/E-cone design here:

http://www.hostboard.com/forums/hbmc...2013/03/16.jpg

He specifies a 1.6mH air core inductor @ .3 Ohms made from 16 AWG wire. However, when I look at this inductor calculator Shavano Music Online - Cross-Over Network; Air Core Inductor Calculator and plug in 1.6mH you get this result:

http://www.hostboard.com/forums/hbmc.../2013/03/1.png

My confusion is that in order to get a .3 Ohm value you need 14 AWG wire, not 16.

Same with the 1.1mH. In order to get to his stated value of .235 Ohms, you also need 14 AWG wire.

Inquiring minds want to know what I'm missing.

- - - Updated - - -

Things get dicey when you get to the 4.7mH. He calls for 14 AWG. Again, plugging into the calculator it seems I would need 230' of 14 AWG wire to make this inductor. That's a lot of copper.

http://www.hostboard.com/forums/hbmc.../2013/03/2.png

If I make this 4.7mH inductor from 18 AWG wire, I only need 191' of much cheaper wire, but my DCR doubles from .58 to 1.22 Ohms.

The question is: what effect will that have on the whole loudspeaker package? I assume that more resistance will generate more heat and it will also absorb a percentage of the wattage available to the driver. Since I will likely be driving my 604s with 1.5W monoblocks, I would like to retain all the power I can.

So the bigger the gauge the better for this purpose? And at what point does the sublime meet the ridiculous?

BTW, after starting to shop for wire it made me realize that Bill's price for his 1600 XOs at $178 are quite reasonable: Altec Lansing GPA N1600 16 Crossover New | eBay . Copper t'aint cheap.

alancohen
If I were making this XO, I would use # 15 AWG and shoot for an average of 0.5 Ohms per coil.
Buy 10 # ( pounds ) of magnet wire.
The bigger the wire the lower the loss. We are talking a few tenths of a dB.

Don

Big thanks, Don. The words "If I were making this XO, I would use..." from someone of your experience are like fine music to my ears. I guess I have some coil winding in my near future.


BTW, this is where they are going...with a couple of 300B monoblocks on the mantle.

http://www.hostboard.com/forums/hbmc...2013/03/37.jpg

The 604s have been just laying around the LR so I thought I'd get them out of the way and install them back into their old home. Not much else to do while I wait for my inductor wire.

Some decent grille covers came with the cabs, but it sure is a shame to cover them up.

Now the cabs officially weigh a ton. I know the black and wood grain look is a bit tacky, but my whole living room is wood floors and ceilings with black furniture. They oddly fit right in.

http://www.hostboard.com/forums/hbmc...2013/03/41.jpg

Hate to say this, but if that were my room, I would tear that fireplace the hell out of there. Sorry, that's just me, but what a mess.

I don't know about tearing out the fireplace but I would seriously think about sliding them to the opposite side of the step from the fireplace. Having them up tight to the side of the fireplace might not be an optimum placement.

Quote:

---

Originally Posted by VolvoHeretic

Hate to say this, but if that were my room, I would tear that fireplace the hell out of there. Sorry, that's just me, but what a mess.

---

Well considering my house is heated predominantly by that fireplace, it is not likely.

Quote:

---

I don't know about tearing out the fireplace but I would seriously think about sliding them to the opposite side of the step from the fireplace. Having them up tight to the side of the fireplace might not be an optimum placement.

---

That is certainly an option, but too far apart will likely destroy the stereo image. I'm thinking about building a little riser in between the step and the base of the fireplace which will allow moving the speakers forward about a foot. At least that would get the baffle about 4" in front of the fireplace. We'll see.

That was gonna be my second suggestion. ;) you might want to check how hot it gets there with a roaring fire before you find your horns drooping. :(

Quote:

---

Originally Posted by cradeldorf

That was gonna be my second suggestion. ;) you might want to check how hot it gets there with a roaring fire before you find your horns drooping. :(

---

Why shouldn't my horns start drooping. Everything else has.

There's a fan built in to the stove that blows straight out. The stone is so big that it just gets warm, but never hot. Even the back side where I sit gets nicely warm. Pretty creamy, but not ideal for a recording studio.

I started collecting parts for Jeff's XO. He specifies a 3.7uF cap. I can't find any. I can find a 3.9, or I can get a 2.2 and a 1.5. Which is best? I hate adding extra parts. The 3.9 is a 5% difference. The Chicago caps I replaced from my Heathkits were +/- 10%. So how critical is hitting that number? I'm thinking of using Dayton 1%ers.

I'm like you and prefer to stick with less clutter. either way will probably be pretty unnoticeable.

Quote:

---

Originally Posted by alancohen

I started collecting parts for Jeff's XO. He specifies a 3.7uF cap. I can't find any. I can find a 3.9, or I can get a 2.2 and a 1.5. Which is best? I hate adding extra parts. The 3.9 is a 5% difference. The Chicago caps I replaced from my Heathkits were +/- 10%. So how critical is hitting that number? I'm thinking of using Dayton 1%ers.

---

Regarding the first question..... the standard values for the resistors and capacitors were chosen intentionally in a particular manner so that one can reach any value with the right combination. As 3.7uF is not a standard value, you will have to go for the "combination" route. Here you should go for the 2.2uF & 1.5uF combo.

Now regarding how critical one should be about these values....... well for all practical purposes, a shift of +/- 5% will normally not be audible in most cases. But again it all depends on the driver parameters and the type of xover design, and the placement of the xover "frequency". Also here we are talking about Altec-duplexes and Jeff's work (the critically-computed-types). So we should respect the overall picture and go for the actual values. But I also must add it here that the end result may vary, but even if it does, at least you will have a starting point to tweak your way through.:)

Thanks aditya...good info. I noticed that Jantzen, Dayton, Solen etc all seem to offer the same values. I thought it might just be the result of expediency of manufacture rather than by design.

I emailed Jeff and he was kind enough to assist me. He said to go ahead and use the 3.9. I was glad. In my mind, more parts equate to more potential for failure. He said the same thing CD and you did. It is not likely I will be able to hear any difference. Especially given the fact that most reasonably priced caps are +/- 5% tolerance anyway. I'm using 1% Daytons.

And like you say, that should get me started. I'm not prone to tweak unless something really jumps out at me. I'd rather spend my time listening, than measuring.

Thanks Alan for the 'thanks'. You are welcome.

Nice to hear about the go-ahead signal from Jeff. So expectations are that you will post the developments here, which will be great. Actually I have not yet tried this design myself, but CD probably did it, but I am not sure. What I know from his posts is that he is with the GPA ones. He himself only can conform this, as his present avatar of the 'mad-scientist-image' throws me completely out of my resources.:) (hi CD !) But I am sure Jeff's design will definitely work nicely. Have a great Altec-Duplex-journey.

Aditya

Quote:

---

Originally Posted by aditya

Nice to hear about the go-ahead signal from Jeff. So expectations are that you will post the developments here, which will be great.

---

I certainly will. I'll post the whole build, including pics. Right now I'm wrestling with the layout and hook up hardware. I can never seem to find everything I need from one place.

I'm using the inductor calculator here...Inductor Designer / Calculator

Using a value of 4.7mH with 15 AWG wire, a core of .75" and length of 1" I get a DCR of .5 Ohms. 19 levels with 17.5 turns will make a pretty symetrical coil. Good?

Inductance 4.7 mH
DC Resistance 0.5 Ohms
Wire Gauge 15 AWG
Wire Diameter 57.1 mils (1 mil = .001 in)
Coil Length 1 in
Coil Inner Diameter 0.75 in
Coil Outer Diameter 2.92 in
Average Turn Diameter 1.77 in
Wire Length 152.58 feet
Copper Weight 1.5 pounds
Turns 330
Levels 18.84
Turns/Level 17.51

Hi Guys, :) The parts express catalog shows all inductors and their DCR's and impedance's, It comes in handy for hunting inductors. You can always use your DATS to measure the caps...and everything else for that matter just to see where they're at. I have never built one of Jeffs Crossovers and right now my GPA crossovers are collecting dust.

HI guys
COIL winding: Try to pick the coil form so cross section is square and the finished hole radius is the same dim.
This will minimumise the length of wire, DCR , and turns for a given mH
CAP values: Give the designer a break.
If the design calls for 3.7 do not sub a 3.9. Use a 2.7 plus a 1.0 or some other combo. And do not tell me
it looks ugly with all those caps. We want the best performance. i have built a number of pretty XOs that did not work as expected. Some did not work worth a dam. OK I will get off the soap box . I apologize if I stepped on any toes.
Don

Now I'm confused. I'll build the XOs to plan and then re-examine the hook up after.

As far as the inductors, using the calculator above I get a pretty symentrical 4.7mH by using 1" length and 1" core:

Inductance 4.71 mH
DC Resistance 0.51 Ohms
Wire Gauge 15 AWG
Wire Diameter 57.1 mils (1 mil = .001 in)
Coil Length 1 in
Coil Inner Diameter 1 in
Coil Outer Diameter 3.06 in
Average Turn Diameter 1.94 in
Wire Length 156.03 feet
Copper Weight 1.54 pounds
Turns 307
Levels 17.53
Turns/Level 17.51


But if I go .4" core with .4" length, the overall diameter jumps from 3.06" to 4.17, but the DCR drops to .44 and wire required is reduced as well. That makes for a flat looking inductor, and probably harder to wind, but the values are better.

Inductance 4.72 mH
DC Resistance 0.44 Ohms
Wire Gauge 15 AWG
Wire Diameter 57.1 mils (1 mil = .001 in)
Coil Length 0.4 in
Coil Inner Diameter 0.4 in
Coil Outer Diameter 4.17 in
Average Turn Diameter 2.23 in
Wire Length 135.19 feet
Copper Weight 1.33 pounds
Turns 232
Levels 33.12
Turns/Level 7.01

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

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

Quote:

---

Originally Posted by cradeldorf

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

Quote:

---

Originally Posted by 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.

---

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

Quote:

---

Originally Posted by alancohen

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

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.

Quote:

---

Originally Posted by 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.

---

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.

Quote:

---

Originally Posted by alancohen

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 - - -

Quote:

---

Originally Posted by alancohen

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

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 :confused:

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

http://www.hostboard.com/forums/hbmc...2013/03/51.jpg

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

http://www.hostboard.com/forums/hbmc...2013/03/52.jpg

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...

http://www.hostboard.com/forums/hbmc...2013/03/53.jpg