roll my own "output isolators" ?

[Freq Band]

Similiar to this one:
http://www.jensen-transformers.com/datashts/oli3.pdf

On the Headwize site, Toni Kemhagen's submission tells us how to wind a 3.9mH air-core inductor:
(3/4 down the page..)
http://headwize.com/projects/showfile.php?file=kemhagen_prj.htm

Question is.......can that be wound over (around) the output resistor?
Would that need to be a carbon resistor?........a metal film resistor has .....metal in it. (???)

=FB=

 

[NewYorkDave]

Don't mix up uH and mH. There's a big difference.

A 3.9uH inductor is easily wound over a decent-sized resistor. Use the formulas for a single-layer solenoid. Use carbon if it makes you feel better--the resistor is effectively shorted out at audio frequencies, anyway.

 

[Freq Band]

[quote author="RogerFoote"]Or put a resistor in parallel with a choke.[/quote]
Yes, this what I meant.....only the coil is wrapped around the resistor, soldered at both ends, effectively being wired as parallel. :grin: .....saving space, and supporting the windings.

NYD...no, carbon is not my first choice......but I am assuming there is a reason these inductors are often specified as "air core" rather than ferrite.
So, does it matter what's "inside" the coil ?

----------

Can someone ship me some Swiss Alpine air ?
Exotic core material.
:wink:

=FB=

 

[Samuel Groner]

So, does it matter what's "inside" the coil?

Ferrite might distort with low loads, air tends to be much more linear. See www.groupdiy.com/index.php?topic=16953 as well.

Can someone ship me some Swiss Alpine air?

Sure! Give me the required capacity and I'll give you a quote...

Samuel