Mario,
I find your typing a little too confrontational and decline to reply.
Best wishes in the coming new year!
Erik
If you build a very low distortion power amp, any core in the output inductor, even an inadvertent one, will increase the distortion measurably. We're talking very low value inductors there. Has anybody looked at the distortion caused by iron core inductors used in a crossover? FWIW, I use air cores whenever possible, and it's almost always possible.
What I found in my coil-rig test, whether you believe me or not, is that I-cores can give a bit of 'slam' or emphasis in the bass range, to the point of being 'heavy' sounding depending on the design and bass alignment/BSC. That said- it was preferred by the masses at one event. Who doesn't like bass?
What I also found out is that I prefer air-cores and litz air-cores to P-cores and I-cores, but would not use P-cores if I can avoid them. P-cores sounded like the killed the detail, and/or muffled it. The funny thing also is that I preferred the Air/Litz to the Foils. Foils weren't bad, but the round/litz were just better.
I do have plans to try the C-coils in comparison at some point, just for the heck of it....
I have used them before.
Later,
Wolf
What I also found out is that I prefer air-cores and litz air-cores to P-cores and I-cores, but would not use P-cores if I can avoid them. P-cores sounded like the killed the detail, and/or muffled it. The funny thing also is that I preferred the Air/Litz to the Foils. Foils weren't bad, but the round/litz were just better.
I do have plans to try the C-coils in comparison at some point, just for the heck of it....
I have used them before.
Later,
Wolf
Interesting, I have also seen comments on I-cores tweaking the bass output (if you are talking about the steel laminate ones). I use ferrous cores with discs in a commercial design and I do like their bass performance (they have massive cores that would saturate at little under 500W). I think using a cored coil is not a problem (even for midrange duties) for as long as the saturation of the core becomes noticeable at much higher power levels than the max stated ones for a specific project.
Erik, questions were rhetoric. Merry Christmas!
Erik, questions were rhetoric. Merry Christmas!
Nothing wrong with Jantzen P-cores and have never heard any detrimental effects. I've used plenty over the years but usually in large values > 4mH but have gone as low as 1mH.
When making comparisons, variations in DCR can effect the filter and driver Q. Higher resistance will give an impression of lower bass.
Simple Network Lowers f3
When making comparisons, variations in DCR can effect the filter and driver Q. Higher resistance will give an impression of lower bass.
Simple Network Lowers f3
That's more dependant on the magnetic permeability of the of the core than the geometry of the core. If you use a core with higher magnetic permeability then you need less turns to achieve a certain inductance and less turns = lower DCR.
The problem with using a higher permeability core material is that they generally saturate at a lower flux density and/or exhibit hysteresis. That is why speaker crossover inductors generally use a low magnetic permeability core - AL=10 or less usually - giving a few fold reduction in the number of turns needed therefore reducing cost and DCR without introducing significant distortion.
One thing to note is that DCR is not necessarily always a bad thing. In certain cases having a few ohms DCR can aid hitting the correct slope in a crossover design, allowing you to use modestly priced air cores.
Last edited:
Conductors creates a huge amount of interference or crossover distortion as a rule. Adding a core means adding even moore distortion but reduces the serial resistance wich is a (the) dynamics killer.
Foil-conductors gives wery low distortion compared to round thread conductors but they will, like regular conductors, reduce dynamics if they are to small. Foil equivalent to 2.5mm diameter round copper wire is a minimum if you want a small midrange unit to perform. Definetly worth the money in a well tuned system. Best choise in mid-range.
Mundorf Air-core Copper Foil coils, CFC range | Hifi Collective
The only solution worth mentioning when it comes to passive bass-filtering is transformer conductors. Minimum here is 6mm thread, or 9awg. Thinner thyread will reduce dynamics too much. Thicker thread though, like the 6x2mm rectangular used in the Mundorf-Null-OHM-Spule both gives close to zero resistance and reduced interference distortion. Openes for quite lively dynamics if matched with equivalent speakercables. =minimum 2x6mm pr. conductor, solid core off course.
https://www.hifisound.de/de/Lautspr...e/Eisenkern/Mundorf-Null-OHM-Spule-N-390.html
Then if you choose the right suited drivers you can keep the filters no moore than 1.order. If not, go for an active solution.
Foil-conductors gives wery low distortion compared to round thread conductors but they will, like regular conductors, reduce dynamics if they are to small. Foil equivalent to 2.5mm diameter round copper wire is a minimum if you want a small midrange unit to perform. Definetly worth the money in a well tuned system. Best choise in mid-range.
Mundorf Air-core Copper Foil coils, CFC range | Hifi Collective
The only solution worth mentioning when it comes to passive bass-filtering is transformer conductors. Minimum here is 6mm thread, or 9awg. Thinner thyread will reduce dynamics too much. Thicker thread though, like the 6x2mm rectangular used in the Mundorf-Null-OHM-Spule both gives close to zero resistance and reduced interference distortion. Openes for quite lively dynamics if matched with equivalent speakercables. =minimum 2x6mm pr. conductor, solid core off course.
https://www.hifisound.de/de/Lautspr...e/Eisenkern/Mundorf-Null-OHM-Spule-N-390.html
Then if you choose the right suited drivers you can keep the filters no moore than 1.order. If not, go for an active solution.
I hand wound some test coils, not really for crossovers ~0.2mH 0.5 ohm DCR. These had something like 80 turns in 4 layers on a small plastic core. I had put a layer of electrical tape between every layer to try and keep the coil tight. They were very noisy, acted almost like magnetostrictive speakers. At low frequencies they would vibrate in hand. That experience made me lose interest in making coils 
. Hard to save money without buying lots of wire (defeats the purpose) and could create new issues...
. Hard to save money without buying lots of wire (defeats the purpose) and could create new issues...This is a very interesting topic!
I have been working on a small bookshelf with a very high cross-over frequency (at 4.8khz!) and fine tuned it with a cheap €3 1.0mh Jantzen P-core, and I feel like I am missing some detail on the midrange, it sounds a bit muffled...
I just ordered a pair of €16 each 1.0mh air cored inductors with similar values of inductance and dcr, but with AWG14 wire, so I will report back on my findings about this, should be fun!
I have been working on a small bookshelf with a very high cross-over frequency (at 4.8khz!) and fine tuned it with a cheap €3 1.0mh Jantzen P-core, and I feel like I am missing some detail on the midrange, it sounds a bit muffled...
I just ordered a pair of €16 each 1.0mh air cored inductors with similar values of inductance and dcr, but with AWG14 wire, so I will report back on my findings about this, should be fun!
If I spend about $100 (free shipping) for the equivalent copper 14AWG in that 10 pound spool size, I can wind more coils than what I can purchase in 14AWG standard varieties.
I wound 8 coils with that 10 pounds. 2x 0.9mH, 2x 1.5mH, 2x 0.35mH, and 2x 0.47mH.
Per PE's new Dayton bargain-coil 14AWG pricing:
2@17.70/2@23.25/2@11.43 (0.4mH price)/2@12.83 (0.51mH price)
The last 2 would be ~$10 and ~$12.50 respectively if you fudge to get exact value. I get $126.92 with the reduced fudged numbers.
So- I saved about $25-30/spool give or take winding my own, and my values are correct and don't need checked or unwound to value. Less than 1% tolerance and getting exactly what I need while saving money suits me just fine.
Oh- and dunk the coils in polyurethane when you're finished. That will stop the resonating.
Later,
Wolf
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
How much time did you spend to save $27?
You learned something, and have a story to tell, but in my estimation it wasn't worth the trouble for you, either....
I too have used Jantzen P-cores for years and never though them to be inferior.
P-cores and laminated cored chokes should only be used in moderately rated sytems, not for those high powered systems that was demonstrated in the link below.
The Loudspeaker Crossover Part II: Measurements & Conclusions | Audioholics
At the lower frequencies around 100c/s one's bass drivers are entering into the realms of high harmonic distortion anyway so any harmonic distortion added by an iron cored inductor not entering into saturation is going to be swamped by that inherent in the driver.
Let alone that produced by cabinet colouration. We live in a world of compromises and tweaking the best out of it is the best we can do.
C.M
P-cores and laminated cored chokes should only be used in moderately rated sytems, not for those high powered systems that was demonstrated in the link below.
The Loudspeaker Crossover Part II: Measurements & Conclusions | Audioholics
At the lower frequencies around 100c/s one's bass drivers are entering into the realms of high harmonic distortion anyway so any harmonic distortion added by an iron cored inductor not entering into saturation is going to be swamped by that inherent in the driver.
Let alone that produced by cabinet colouration. We live in a world of compromises and tweaking the best out of it is the best we can do.
C.M
Maybe an hour to make the jig, and 2-3 hrs more to wind them. It's not really time prohibitive. It sure gives your wrists a workout though!
It's much less money in the long run, as I have other wire gauges on hand. I don't have to spend shipping money for needed coils, nor tax for 'local' pickup if I go to Dayton. The only times I need coils is for the laminated styles. I find the Laminated and the air-coils the best of what I've tested, and have since distanced myself from the P-core styles.
I really don't buy coils much anymore, and am on my second 10# spools for 16 and 18AWG.
Later,
Wolf
I am also one of those freaks that likes to make their own coils so after having enough of forearm workout, finally came up with an idea to speed things up.
http://www.diyaudio.com/forums/equipment-tools/295848-diy-coil-winder.html
http://www.diyaudio.com/forums/equipment-tools/295848-diy-coil-winder.html
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.