source for NYD eq inductors?

i have to say that this type of thread is great for a newbie like me.
thank you CJ and Wavebourn!! :thumb:
i love uncle CJ, he's both winder and destroyer of magnetica! he giveth and he taketh away. :green:
CJ - the CJ-2503 pair you made for me is finally going to see action soon! :grin:
thanks again for those! (sorry OT - rage on ye inductor winder!)
-grant

Thanks for the props, I love this xfmr crap, otherwise I would be home smokin crack.

Wavebourn, sounds like you know some stuff, good to see you here!

There are some new powdered cores that have come out in the last ten years that have good Al numbers like steel, but the same hi freq properties as ferrite. So there are so many blends, it's hard to generalize about these typs of coers nowdays. But yes, you have to watch the saturation. If the Al is too high, you don't get the turns on there, and then the B max goes up.

I am going to mess with some back and forth pie windings on this next batch to see if I can get the pass band elevated.

Carbon iron?

I have not seen it about 30 years...

Holy cow, that makes you 50+. Me too.
Across the pond in Mt View.

Check the product line here:

http://www.mag-inc.com/

Here is a cool thread on powdered cores at )gulp) another forum:

http://www.diyaudio.com/forums/showthread/t-55929.html

49, this Monday.

Thanks for links!

BTW, how often do you drive North?
I worked in Mt View, till September.

Did some ,ore tests on the 820 mH powdered inductor

actual inductance at 555 hz- 820 mH

measured inductance:

Sencore: 724 mH
BK: 910 mH
Gen Rad: 630 Mh

I then put in in series with a 0.82 uf poly cap in series with the 820 mH.
Resonance should be lower, around 196 hz.

If the resonant frequency is different, that means that the iductance has changed with frequency.

Well, the real resonant freq of the 0.82 and 820 mH was 186 hz.

Thsi means that the inductance went from 820 mH at 555 hz to 914 mH at 186 hz.

This is a percent change of about 11%.
This is why you kind of have to know what frewquency the inducttyors you buy were measured at.

OK, that was inductance vs frequency, what about inductance vs level?

Well at 10 Vvolts P-P, we have a res of 166 Hz.
At 1 volt and 100 mv P-P, the resonance changes back to 191 Hz.

At 10 V P-P, the inductance changed from 914 mh to 1.14 Henries.

This is a change of about 8%.

So you can see this inductance biz is not exact science.



Working with this tape wound core now.

Put on 250 turns, Al number is 1200.
Put on 600 turns, Al number jumps to 6000.

Looks like the perm is changing with the turns.
Maybe a minimum amount of turns is needed yto jump start the steel core.

As I told, slow saturation. Good for line transformers, bad for tuned circuits.

Wow, it took 460 turns on the steel core to get the same henries as the 250 turns on the powdered core, so the powder core actually has a higher perm.

Maybe I will ship both so the sonic differences could be had.

I would always be willing to build two .. and we can compare the results

im really interested in the actual audible difference

-richie