Question re the foil inductors: I've yet to try them, as I am curious how difficult unwinding to a targeted value. I.e. is there a bit of adhesive to somewhat hold together as you peel off, or do they just unwind like a watch spring?
I don't think you want to try and unwind a foil coil, Andy, unless you are making flat foil speaker cables and won't be planning on using them as coils again.
There are varying grades or constructions, all usually taped at minimum, or heatshrink around the perimeter. Some seal the winding edges into a melted bonded hard surface, which is preferable in terms of structure and longevity. Others you could slide like a telescope. I tend to squirt E6000 into the unbonded ones to make them more sturdy. Dunking in polyurethane is an alternative.
I’ve read that. My Litz type coil never showed yet so was trying to find something with or around the same dcr. I might just order a set of foil inductor from madisound and cancel the other sample order.
I’ve not spared any expense on this build so that’s why I’m using all Foil Inductor and all Copper Caps.
As for Jfcomponents, I wanted a little bit more high-end type of inductor To add to our line of products
@jr@mac said:
P-Core should not be used for any application that will see more than several watts, they saturate at low power.
I'm not sure about that. I've used them several times in projects and they never sounded like shit at pretty high volumes. I think I still have a pair or two in my parts stash (4 mH and ~ 1 mH IIRC). I might wire up a test rig to see how much power to the driver before the series P-core inductor saturates. It is easy to measure because the inductance drops to "air core" inductance of the windings when the ferrite core saturates.
I thought you showed a distorting Pcore not that long ago, Craig, with an image showing proof.
I have used the Pcore in the past, but have preferred Icore or air in direct comparison testing. I have used foils when they were available from my stash in the correct value, and have not really been disappointed vs standard air core. I used 12awg foils in the Monoculus, and those sound phenomenal to me. I have 14awg air in the EMP and on the Cecropia (as preference), and those both sound great as well.
The group consensus on my coil rig with the Cecropia showed that the Icore with the extra slam was preferred most upon short term listening. The crowd did not prefer the Pcore, and especially did not like the foils in that instance.
Anecdotally speaking, I had issues using them to make a low pass crossover for a 8" driver. I was trying to stay in budget and use some of those powder core inductors from a PE buyout. Distortion was audible and increased with volume. At low play back levels they were fine, and I imagine for shunt circuits they would also be fine.
I do remember reading an article years ago where they showed how distortion rises and it starts at a lower level than one would suspect. I cannot remember where I read it, may have been a link posted on PETT but it was years before I tried using one.
I would be curious to see any measurements - I may be off base with what may well be just an opinion.
I remember reading a white paper a few years ago, and internalized the finding to never use powdered core inductors.
There may be better sources, but I found this from a discussion at ASR. Seems pretty complete. https://mtg-designs.com/tips-tricks-tests/inductor-testing
But Chahly - Stahkist don't want speakers that look good, Stahkist wants speakers that sound good!
Thank you Don for posting that. Based on his results I don't feel the need to do any testing myself.
My personal take away is pretty simple... don't use any of those cheapass buyout ferrite powder core bobbin inductors or the ferrite powder core bar inductors (regularly seen in passive car audio crossovers). For low pass woofer filters the Jantzen P-core inductors seem to be fine and don't saturate until several hunndred Watts. That said I think I'll stick with laminate iron core inductors when the series inductor needed value exceeds 1 mH or so. Every inductor below that will be air core, wire gauge dependant on the application. Would my Jantzen 4 mH P-core be ok in a small 5" woofer 2-way? Probably yeah. If they're buyout woofers no problem. For better woofers I'll stick with the 18 gauge laminate cores.
I have been able to "core" some of the ferrite core inductors and use them as air core. Normally you can crack them apart easily. Just plan on the mh value to be cut in half or more.
Comments
I can send some hardwood wine-infused cable lifters.
"AGDC Adjusting Tool". $199
@hifiside I hope you don't mind that I linked your 0.25 ft^3 knock-down cabs on ASR for the Mechano23 diy speakers that were Klippel tested. The baffles are almost exact.
Nope. Link away.
https://www.jfcomponents.com/
I found some 20-year-old gems.
https://www.jfcomponents.com/
Purfi's more attractive daddy?
Got my samples from China this morning. My factory must be right next-door to some other Peoples. 😆
https://www.jfcomponents.com/
Question re the foil inductors: I've yet to try them, as I am curious how difficult unwinding to a targeted value. I.e. is there a bit of adhesive to somewhat hold together as you peel off, or do they just unwind like a watch spring?
I’ve never disassembled one yet.
https://www.jfcomponents.com/
I don't think you want to try and unwind a foil coil, Andy, unless you are making flat foil speaker cables and won't be planning on using them as coils again.
There are varying grades or constructions, all usually taped at minimum, or heatshrink around the perimeter. Some seal the winding edges into a melted bonded hard surface, which is preferable in terms of structure and longevity. Others you could slide like a telescope. I tend to squirt E6000 into the unbonded ones to make them more sturdy. Dunking in polyurethane is an alternative.
InDIYana Event Website
Replaced a JF-18ga laminate coil with a P-core style 15ga coil with half the Rdc. I might have to remeasure things.
https://www.jfcomponents.com/
P-Core should not be used for any application that will see more than several watts, they saturate at low power.
I’ve read that. My Litz type coil never showed yet so was trying to find something with or around the same dcr. I might just order a set of foil inductor from madisound and cancel the other sample order.
https://www.jfcomponents.com/
what is the adventage of foil inductors compared to regular?
Here’s supposedly what different.
https://www.madisoundspeakerstore.com/goertz-12-awg/goertz-cf1.5-12-awg-copper-foil-inductor/
I’ve not spared any expense on this build so that’s why I’m using all Foil Inductor and all Copper Caps.
As for Jfcomponents, I wanted a little bit more high-end type of inductor To add to our line of products
https://www.jfcomponents.com/
https://www.jfcomponents.com/
I'm not sure about that. I've used them several times in projects and they never sounded like shit at pretty high volumes. I think I still have a pair or two in my parts stash (4 mH and ~ 1 mH IIRC). I might wire up a test rig to see how much power to the driver before the series P-core inductor saturates. It is easy to measure because the inductance drops to "air core" inductance of the windings when the ferrite core saturates.
I thought you showed a distorting Pcore not that long ago, Craig, with an image showing proof.
I have used the Pcore in the past, but have preferred Icore or air in direct comparison testing. I have used foils when they were available from my stash in the correct value, and have not really been disappointed vs standard air core. I used 12awg foils in the Monoculus, and those sound phenomenal to me. I have 14awg air in the EMP and on the Cecropia (as preference), and those both sound great as well.
The group consensus on my coil rig with the Cecropia showed that the Icore with the extra slam was preferred most upon short term listening. The crowd did not prefer the Pcore, and especially did not like the foils in that instance.
InDIYana Event Website
I don't remember that but maybe. You have a better memory than me.
Well I would love to see some measurement results.
https://www.jfcomponents.com/
I tried to find it, but came up with nil. Even used Google to go broader for more forums since Craig is also a member elsewhere.
However, HifiCompass has a article on it with regard to laminate styles.
https://hificompass.com/en/projects/experiment/test-couple-iron-core-inductors
Found this YouTube vid:
I'll have to check the laptop for the image or such, just in case I saved it...
InDIYana Event Website
Simple enough to test. Maybe after my son and I get home from the NASCAR race this weekend.
Anecdotally speaking, I had issues using them to make a low pass crossover for a 8" driver. I was trying to stay in budget and use some of those powder core inductors from a PE buyout. Distortion was audible and increased with volume. At low play back levels they were fine, and I imagine for shunt circuits they would also be fine.
I do remember reading an article years ago where they showed how distortion rises and it starts at a lower level than one would suspect. I cannot remember where I read it, may have been a link posted on PETT but it was years before I tried using one.
I would be curious to see any measurements - I may be off base with what may well be just an opinion.
I remember reading a white paper a few years ago, and internalized the finding to never use powdered core inductors.
There may be better sources, but I found this from a discussion at ASR. Seems pretty complete.
https://mtg-designs.com/tips-tricks-tests/inductor-testing
Thank you Don for posting that. Based on his results I don't feel the need to do any testing myself.
My personal take away is pretty simple... don't use any of those cheapass buyout ferrite powder core bobbin inductors or the ferrite powder core bar inductors (regularly seen in passive car audio crossovers). For low pass woofer filters the Jantzen P-core inductors seem to be fine and don't saturate until several hunndred Watts. That said I think I'll stick with laminate iron core inductors when the series inductor needed value exceeds 1 mH or so. Every inductor below that will be air core, wire gauge dependant on the application. Would my Jantzen 4 mH P-core be ok in a small 5" woofer 2-way? Probably yeah. If they're buyout woofers no problem. For better woofers I'll stick with the 18 gauge laminate cores.
I have been able to "core" some of the ferrite core inductors and use them as air core. Normally you can crack them apart easily. Just plan on the mh value to be cut in half or more.
I ordered some Jantzen P-Core once and it is my opinion one need only package them poorly and drop them on the floor and they will de-core themselves.
Very true!
Poop core
This is timely information for me. Very good