[JN] magik ???

Grego Sanguinetti grego at sandesco.com
Tue Feb 2 23:03:16 CST 2021

Holy crap! some people have a lot of time on their hands.
How cool is that thing. I love it that he provided so much maker data.
It even has "cum holders"! Damn. It has auto-suck too
I'ld never leave the house...


On 2/2/2021 4:13 PM, Christian Rintelen via Sound wrote:
> so cool!!
> (just in case you’re tired of counting turns: here’s a DIY toroid 
> winder with arduino control 
> <https://electricdiylab.com/diy-arduiuno-based-toroid-coil-winding-machine/ 
> <https://electricdiylab.com/diy-arduiuno-based-toroid-coil-winding-machine/>>
> ©
> _ _ _
> aka christian rintelen
>> Am 02.02.2021 um 21:41 schrieb Hanski <hanskinposti at gmail.com 
>> <mailto:hanskinposti at gmail.com>>:
>> Hi gents, my 2cents.
>> magnetic energy is stored in an air gap.
>> So if you need to store energy in a choke, you need an air gap.
>> Sendust like other powder cores have a distributed air gap (there is 
>> always some air between powder particles).
>> Sendust is used in SMPS because it’s cheap and has lower magnetic 
>> flux swing related losses than plain iron powder cores.
>> Usually they come in toroid shapes. One could also use a gapped 
>> ferrite toroid there, but it’s usually a bad idea because you would 
>> need to locate all windings on top of the air gap to cancel the 
>> external flux (less outside flux, less EMC).
>> Other powder core materials:
>> https://www.coilws.com/index.php?main_page=page&id=41 
>> <https://www.coilws.com/index.php?main_page=page&id=41>
>> -Hanski
>> P.S. I really like homemade audio transformers.
>> For small signal stuff one can use even plain SMPS ferrite. a few 
>> thousand turns primary gives 200H inductance (Al = 12u) with commonly 
>> available  ferrite toroid. (No DC bias)
>> Just wound a couple with 50um thick wire. (My skills don’t go below 
>> that, it’s already human hair thick) :)
>> <Toroid.jpeg>
>>> ©
>>> PS i’m not so sure Sendust would be that good for a transformer 
>>> core. Sendust (aka Kool Mu) is often used in power supply chokes … 
>>> because it stores energy well. is the capability to store energy 
>>> better than other materials a good thing in an audio transformer? i 
>>> don’t know (no irony). but i can imagine that the release of the 
>>> stored energy «smears» the timing. isn’t the best core … an air 
>>> core? because it does exactely the opposite — it doesn’t store any 
>>> energy?  (btw. Sendust has seen wide spread use in audio when tape 
>>> and cassette recorders were still mass produced. many of the better 
>>> recorders used Sendust heads because it is very hard.)
>>> _ _ _
>>> aka christian rintelen
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