Hi,
I´m about to build myself a new crossover for my Altec Duplex 604E´s.
So I´ve bought almost all the parts for this new crossover.
This crossover will have same specs as the original Altec Lansing N1500-A crossover.
I´ve used Jeff Markwart's Corner as a great help - this is the one resource I´ve used - great site! -Link: Recommended Parts - Substitutions - Construction Hints
So he suggests Copper Foil Air Core (CFAC) inductors for this crossover.
And I want to use CFAC inductors.
I´ve found these inductors from Mundorf:
Mundorf - Inner Excellence
The inductor on this crossover has the value of 1.5mH, but I have no idea which thickness to choose.
Is these anybody out there that can tell me which one to choose?
All help will be really appreciated 🙂
Best,
Endre
I´m about to build myself a new crossover for my Altec Duplex 604E´s.
So I´ve bought almost all the parts for this new crossover.
This crossover will have same specs as the original Altec Lansing N1500-A crossover.
I´ve used Jeff Markwart's Corner as a great help - this is the one resource I´ve used - great site! -Link: Recommended Parts - Substitutions - Construction Hints
So he suggests Copper Foil Air Core (CFAC) inductors for this crossover.
And I want to use CFAC inductors.
I´ve found these inductors from Mundorf:
Mundorf - Inner Excellence
The inductor on this crossover has the value of 1.5mH, but I have no idea which thickness to choose.
Is these anybody out there that can tell me which one to choose?
All help will be really appreciated 🙂
Best,
Endre
Measure the dc resistance of the original coil and choose accordingly. Also replacing NPE caps with film caps can make the sound different because the ESR of the caps may differ. I said different not better.
I don´t have the original N1500-A crossover... I´ve got a GPA crossover
Hi David!
Thanks for posting.
I do not have the original N1500-A crossover....
I got a GPA crossover.
Regarding the caps : I´ve bought Musicap (film + foil polypropylene) capacitors
What do I do then about the inductors- Any idea?
Endre
Hi David!
Thanks for posting.
I do not have the original N1500-A crossover....
I got a GPA crossover.
Regarding the caps : I´ve bought Musicap (film + foil polypropylene) capacitors
What do I do then about the inductors- Any idea?
Endre
Oddly enough I agree with David L... 😀
The DCR of the inductors was part of the xover design.
What you might want to do is to do some measurement of the driver without the xover, maybe when doing the HF section use a simple high pass set below the target xover freq by 1 octave (to protect the VC from LF) and see what the raw driver actually does.
Why do I say this? Because in every control room setting I have seen the 604, copious amounts of EQ were applied to flatten the response. This makes me think that the original xover perhaps might be improved upon via the addition of some additional elements, perhaps in the form of Zobel circuits, notches (high or low Q), shelving, etc...
Why do you think a new xover will be better than the GPA, why is it needed?
You might want to consider doing a biamp set up, that might be the best approach as you can then tailor the amps and xover for a single driver, and you can employ active xover/EQ if you wish too...
The DCR of the inductors was part of the xover design.
What you might want to do is to do some measurement of the driver without the xover, maybe when doing the HF section use a simple high pass set below the target xover freq by 1 octave (to protect the VC from LF) and see what the raw driver actually does.
Why do I say this? Because in every control room setting I have seen the 604, copious amounts of EQ were applied to flatten the response. This makes me think that the original xover perhaps might be improved upon via the addition of some additional elements, perhaps in the form of Zobel circuits, notches (high or low Q), shelving, etc...
Why do you think a new xover will be better than the GPA, why is it needed?
You might want to consider doing a biamp set up, that might be the best approach as you can then tailor the amps and xover for a single driver, and you can employ active xover/EQ if you wish too...
Hmmm...
Hehe...!
What your suggesting is definitely a project for a longer time period.
I`m definitely up for the challenge!
I wanted to try out the N1500-A crossover only because I´ve read it`s hard to match....
BUT:
If I`m going to go down the road your talking about; then Bi-amp is probably the best solution for me ... ( your first suggestion sounded quite a large task to do from my novice stand of these things... )
OK, more info about my current equipment regarding a Bi-amp setup:
So I got a 2a3 tube amp. driving the HF?
And then I got a 30WPC into 8 ohm EL34 push pull tube amp. Low frequency?
I also have a passive pre amp that is suited for my 2a3 tube amp- but I have no idea if this pre will work with my EL34 tube (integrated) amplifier also.
I also got a 10K DACT attenutator... meant for another system.
Question:
What type of measuring tool(s) will I need for measuring what you call the "raw driver" - ( the actually the speakers I got )?
Hehe...!
What your suggesting is definitely a project for a longer time period.
I`m definitely up for the challenge!
I wanted to try out the N1500-A crossover only because I´ve read it`s hard to match....
BUT:
If I`m going to go down the road your talking about; then Bi-amp is probably the best solution for me ... ( your first suggestion sounded quite a large task to do from my novice stand of these things... )
OK, more info about my current equipment regarding a Bi-amp setup:
So I got a 2a3 tube amp. driving the HF?
And then I got a 30WPC into 8 ohm EL34 push pull tube amp. Low frequency?
I also have a passive pre amp that is suited for my 2a3 tube amp- but I have no idea if this pre will work with my EL34 tube (integrated) amplifier also.
I also got a 10K DACT attenutator... meant for another system.
Question:
What type of measuring tool(s) will I need for measuring what you call the "raw driver" - ( the actually the speakers I got )?
Wait, you are going to substitute a crossover from a different speaker into yours? I thought you were just replacing parts in your current crossover. You are in for a BIG job.
I suggest you read through this to get an ida of what is involved to do this right.
The Speaker Building Bible
I suggest you read through this to get an ida of what is involved to do this right.
The Speaker Building Bible
Thanks for your replay.
I definitely got carried away there... sorry for that.
It would have been a BIG job to do make a new crossover from scratch.
You can relax: I`ve not any plans of doing so.
To answer your questions and bringing the subject back to where it began:
1. I am planning of building this clone/DIY : N1500-A crossover.
2. I got the original schematics. I can read simple schematics.
3. I got all the parts I need to build this crossover except the two inductors I`ll need.
4. I have a pair of Altec 604E Duplex speakers in DIY 612C cabs. Today I am using a GPA crossover.
I just have to figure out which inductor to get....
Will keep you posted.
I definitely got carried away there... sorry for that.
It would have been a BIG job to do make a new crossover from scratch.
You can relax: I`ve not any plans of doing so.
To answer your questions and bringing the subject back to where it began:
1. I am planning of building this clone/DIY : N1500-A crossover.
2. I got the original schematics. I can read simple schematics.
3. I got all the parts I need to build this crossover except the two inductors I`ll need.
4. I have a pair of Altec 604E Duplex speakers in DIY 612C cabs. Today I am using a GPA crossover.
I just have to figure out which inductor to get....
Will keep you posted.
I come back to a question unanswered, why do you want/need a different xover than the GPA??
----------------
As far as biamping with a 2A3 SE amp on top?
The answer is to determine how much attenuation is applied in the stock xover, taking into account any shelving or other response slope adjusting in the stock xover (I don't know that answer since I have not done more than a casual look at the stock xover, and that maybe more than a decade ago). Once you know that, then you'll be able to figure out the relative sensitivity of the cone vs the compression driver/horn.
That difference tells you how much power you need to equal the SPL of the proposed 30 watt amp that would drive the cone part.
Or similarly that will tell you the max SPL the speaker will put out, that being the limit (presumably) determined by the power of the 2A3 amp and how loud the compression driver will play as a result.
The goal is to have the two sections end up with just about the same headroom/max SPL - the power required to do that being a function of the drivers for each range, and therefore being different amounts (watts)
-----------------
I don't think that doing a new xover using freeware/shareware measuring gear, and maybe a DSP based xover box would be all that demanding. I'd agree that for a newbie there would be a steep learning curve, but in reality besting the old 604 xover ought not be terribly difficult. As I mentioned, the pros who used them for monitoring EQ'd the carp out of them to begin with...
A purist approach would be more demanding, but having solved it with digital stuff, one would have a good target to figure out what the "purist" analog realization would need to be.
And, you can get help here quite often. 😀
_-_-
----------------
As far as biamping with a 2A3 SE amp on top?
The answer is to determine how much attenuation is applied in the stock xover, taking into account any shelving or other response slope adjusting in the stock xover (I don't know that answer since I have not done more than a casual look at the stock xover, and that maybe more than a decade ago). Once you know that, then you'll be able to figure out the relative sensitivity of the cone vs the compression driver/horn.
That difference tells you how much power you need to equal the SPL of the proposed 30 watt amp that would drive the cone part.
Or similarly that will tell you the max SPL the speaker will put out, that being the limit (presumably) determined by the power of the 2A3 amp and how loud the compression driver will play as a result.
The goal is to have the two sections end up with just about the same headroom/max SPL - the power required to do that being a function of the drivers for each range, and therefore being different amounts (watts)
-----------------
I don't think that doing a new xover using freeware/shareware measuring gear, and maybe a DSP based xover box would be all that demanding. I'd agree that for a newbie there would be a steep learning curve, but in reality besting the old 604 xover ought not be terribly difficult. As I mentioned, the pros who used them for monitoring EQ'd the carp out of them to begin with...
A purist approach would be more demanding, but having solved it with digital stuff, one would have a good target to figure out what the "purist" analog realization would need to be.
And, you can get help here quite often. 😀
_-_-
Bear,
I did answer your question:
But surely I can give a little bit longer explanation:
1. On the site I`m talking about in my first post:
The original N1500-A crossover has been thoroughly examined.
I`m guessing that you also mention this: This crossover (the original N-1500A) is a "purist" design- because of its simple design.
2. It is explained at this site that you can make much more complex crossovers for the Altec 604E´s, ( but that has roughly the same performance )
3. The GPA crossover does do currently a good job with my speakers, but I´m thinking that I do have to gain something by making a N1500-A crossover with "other components".
I do get your point about the way of examining and testing the speakers before going the purist way... but still: I´ve now decided to do this "MY WAY" and not the "HARD WAY".
Thanks again for posting, Bear 🙂
PS:
Will keep you posted on the building of these two crossovers, and how it sounds....
I did answer your question:
But surely I can give a little bit longer explanation:
1. On the site I`m talking about in my first post:
The original N1500-A crossover has been thoroughly examined.
I`m guessing that you also mention this: This crossover (the original N-1500A) is a "purist" design- because of its simple design.
2. It is explained at this site that you can make much more complex crossovers for the Altec 604E´s, ( but that has roughly the same performance )
3. The GPA crossover does do currently a good job with my speakers, but I´m thinking that I do have to gain something by making a N1500-A crossover with "other components".
I do get your point about the way of examining and testing the speakers before going the purist way... but still: I´ve now decided to do this "MY WAY" and not the "HARD WAY".
Thanks again for posting, Bear 🙂
PS:
Will keep you posted on the building of these two crossovers, and how it sounds....
"How it sounds" could have dips and peaks you don't know about and honestly, when people put a lot of time into a project, it always sounds "better". Measuring is the best way to see what is happening. Have fun.
No, I did NOT say that the original xover is in any way a "purist" design.
The number of parts alone is not how that is determined.
If you have a link to the tested results and schematics for the two xovers, I'd be interested in taking a peek at them?
_-_-
The number of parts alone is not how that is determined.
If you have a link to the tested results and schematics for the two xovers, I'd be interested in taking a peek at them?
_-_-
- Status
- Not open for further replies.