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Foil Inductors, why the new trend?


Guest David H

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Guest David H
Foil Inductors, why the new trend?

Where are you seeing this "trend"?

Google it.

There are a lot of companies pushing foils as the best choice.

I also saw in one of the threads here on the forums one member removed the Litz in favor of Foil. Seems like a step backwards.

I have a few but quit using them because Hepa Litz performed better for my application.

ALK and I have been running a few tests, seems although the Litz has the highest Q , the Foils came in second. Both were a far cry better than solid for HF.

Dave

Edited by GotHover
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The reason I ask is because sometimes I wonder if it's the frequency response changes that we are hearing or is it some other aspect of the capacitors or coils that we aren't measuring that's responsible for what we hear.

miketn,

From your signature:

Einstein: "Not everything that can be counted counts, and not everything that counts can be counted"

:)

Hey babadono

Absolutely..!!!!! ......and I believe you will find that didn't stop Einstein from encouraging and relying on others to measure and verify is theories and calculations... :)

miketn

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At some point you have to become comfortable with not fully understanding why you hear what you hear. In other words, I think it's okay to enjoy improvement without measurable evidence of why you're hearing what your're hearing. That doesn't necessarily mean the evidence isn't there, it just means a method for measuring it hasn't been found yet. In some cases it has been found, but some don't want to accept the findings.

Hey Dean I can accept that I will never in all cases fully understand why I hear what I hear and even find great joy regardless but becoming comfortable with not fully understanding why is something I hope never happens to me because that drive to explore for understanding is what leads to advances and is also just plain fun for me... :D

miketn

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These mics and PC tools we use just aren't going to account for all things we hear

While I agree with this statement Mark I will say that (though it's one of the simplest and basic test that can be made and far from definitive of all things audible) if a frequency vs level test of the various networks had been made and there was any variation of even as small as 1db over an octave or two it would be clearly audible IMO. I believe just changing the Q of the coils and the interaction resulting with the rest of the circuit could lead to such variations in the frequency vs level. Now whether that accounts for all changes perceived who knows but I do believe in exploring all aspects when possible.

Now if even this basic test had been done and frequency vs level had been identical between all the networks then that would be much more interesting for sure... :D

miketn

Edited by mikebse2a3
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the DCR is within a couple hundredths of an ohm of the stock iron core. If based on that alone, there shoudn't be any audible difference, but there is. The bass lines are more prominent (defined/easier to follow), and the kick drum has a higher "whack factor". I've got a Jantzen waxed copper foil in the tweeter sections with the Jupiters, which is kind of extravagant for that position.

Lack of HYSTERESIS makes a difference.

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@Mike, Now, now, I said "comfortable" with the idea of a thing, not complacent and sloppy. : )

@Dave, okay I Googled a few different things and I don't see any "pushing" by anyone except maybe GR Research, which I believe is run by Jeff Glowacki's business partner, and I know Jeff really likes the Alpha Cores. I kind of agree with Mark though, if there was a "trend" for these, it was 10 years ago when I was getting a lot of requests to build with them.

Hepa-Litz exhibits less loss at 6kHz, but his plot shows copper foil being superior overall.

The following seems pretty important:

"...additionally, the coil has a tough, yet elastic isolation made from polypropylene foil ensuring a high mechanical stability and, therefore, suppressing vibrations efficiently and effectively."

The Solen Hepa-Litz coils fail miserably in the area of mechanical rigidity - but since they're normally used outside of the speaker, it's not that big of a deal. The point here is that there's more to the performance on an inductor than "Q".

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Guest David H

Dean, I agree, there is more to choosing and inductor than Q alone.

I already stated that page 1 post 7

There is more to consider when choosing an inductor than Q, but from a Q standpoint alone, Foil inductors don't belong in the woofer filter.
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Guest David H
Hepa-Litz exhibits less loss at 6kHz, but his plot shows copper foil being superior overall.

That's not even remotely correct. Just because the foil inductor exhibits a higher Q at frequencies beyond the crossover point does not make it superior.

These are application based components. Best for the application makes a component a better choice.

Do you use a car battery in your watch? It's clearly higher capacity higher voltage and higher current capability. That doesn't make it a better choice for the application.

Dave

Edited by GotHover
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Guest David H

From the components I have tested, the Jantzen P Core looks like a good candidate for woofer filters and Hepa-Litz for the HF sections crossing as high as 15khz.

The Foil inductor was far better than the solid air core but not quite as good as the Hepa-Litz up to 15Khz.

Honestly the Foil inductor performed far better than I expected.

Thanks to ALK for doing the testing. Its nice to have an expert to go to with questions.

Dave

Edited by GotHover
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Guest David H

What does Klipsch use...........the solid? :)

I believe Klipsch uses a combination of solid, iron core, and Ferrite core.

Dave

Edited by GotHover
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Electricity always chooses the path of least resistance. And everything in a crossover Including the drivers is a path. Add more resistance here and the power goes somewhere else to get through. Just remember that.

Edited by cradeldorf
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Guest David H
Dead squirrels reputations are at stake. And you guys want to talk about foil inductors?

Absolutely.

Its has been a peaceful and informative thread.

As always there are a few different opinions, but if everyone agreed there would be no reason for discussion.

BTW, I am sending a few more inductors to ALK for testing. Among them, the Jantzen P-Core, The super Q.

I am very curious to see the results of the P-Core.

Dave

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Well, I'm finally sick of reading about stray capacitance, inductive reactance, etc. The power loss figures are nice to have and I appreciate Al doing them, but he should also listen to the things he measures. These things absolutely kick *** in series with the K-33, so I think I'm going to have to disagree with your "shouldn't be used on woofers" assessment.

The Roadshow Super AA I sent out had a copper foil in series with the K-55, and pretty much everyone loved the sound of that thing. I can only conclude that like capacitors, power loss only forms one part of a bigger picture. I'm sure Al would say a $3 Audyn polypropylene is a better capacitor than a Jensen or a Jupiter, and he would be very wrong - well - if the sound has anything to do with it.

Edited by DeanG
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