Ever tried the type 0 toroids?

[sendler]

Anyone ever tried the type 0 toroid cores to see if they sound more like an air core than the type 2 that is most often recommended?
T130-0

[Pafi]

Why would anybody try a practically non-magnetic core?

[tinitus]

Originally Posted by Pafi

Why would anybody try a practically non-magnetic core?

A toroid will have much less radiation/crosstalk

I suppose its an iron powder core for the small output inductor, and very few windings are needed
Pure iron core I would avoid, if possible

But I dont understand whats new about it

[sendler]

Originally Posted by Pafi

Why would anybody try a practically non-magnetic core?

I would audition the type 0 To try to get closer to the sonics of an air core while still containing EMI enough.
The sonics of the type 2 core are no where near as good as an air core and if I can't find an inductor that will shield AND sound good, I will have to abandon class D and go back to class AB.

[Pafi]

I suppose its an iron powder core for the small output inductor, and very few windings are needed

Maybe it's iron powder, but it has only 50 % bigger permeability then air, so I would say its almost nothing. Al=1.5 nH/turns^2 --> 20 uH needs 115 turns. I wouldn't say it's very few. A little bigger plastic or wooden ring will do it as well as this expensive ****.

sendler! If you want something like air-core, then use air-core! If the choke forms a toroid, then the radiation will be low. But it needs much more wire then a usual air-core coil!

[wrenchone]

The type 0 core is simply phenolic plastic, so it is equivalent to having an air core, except that you have something on which to wind the wire.

[sendler]

Originally Posted by Pafi

Maybe it's iron powder, but it has only 50 % bigger permeability then air, so I would say its almost nothing. Al=1.5 nH/turns^2 --> 20 uH needs 115 turns. I wouldn't say it's very few. A little bigger plastic or wooden ring will do it as well as this expensive ****.

sendler! If you want something like air-core, then use air-core! If the choke forms a toroid, then the radiation will be low. But it needs much more wire then a usual air-core coil!

I have some single layer cylindrical air core filters built but they do pollute an AM radio up to 20 feet away so I only run them for brief comparisons. I have adequate filter response with the inductors down to 6uH so I am looking at 30 inches of wire with the type 2 core versus 90 inches. It's worth a try if no one else has already done it.

[tinitus]

Originally Posted by wrenchone

The type 0 core is simply phenolic plastic, so it is equivalent to having an air core, except that you have something on which to wind the wire.

Ahh, ofcourse

THEN a hardwood toroid core with rounded edges would be nice
Make it yourself, thats not difficult
The best for free

[Pafi]

Air cores do pollute

No, the core doesn't pollute. The wire does, if it's not compensated by other wire (like at a usual toroid). The toroid core does not shield!

[sendler]

What are the draw backs to multiple layers of windings on a toroid if you commit to two full layers? They are used in transformers but rarely seen for inductors.