Inductors in equalizer

[hobiesound]

fablab look at the value ... these are WAY to low to be of any use in the audio band...

 

[Fablab]

I know that they are low for an audio band, but I have posted these to understand if this type of inductor is ok for audio application

 

[bruno2000]

This is what I was referring to, but I have no idea what they sound like.
http://cgi.ebay.com/FASEL-Cup-Core-Yellow-Inductor-for-Crybaby-Vox-Wah-Mod_W0QQitemZ360210946804QQcmdZViewItemQQptZGuitar_Accessories?hash=item53de3edaf4
Best,
Bruno2000

 

[hobiesound]

i just found out that tube amp doctor sells mesa boogie amp eq inductors ranging from 33mH to 1H for around the same price as those fasel's. Funny enough they look like the inductors used in the Odd eq by purple audio. The purple audio site says that ed anderson designed that eq so he might be able to shed some light on that.

greetings,

Thomas

 

[hobiesound]

oh yeah as a side note those fasels are quite expensive for a wha inductor. you can get really cheap tm013 xicon transformers which can be used as a 500mH inductor. I once bought a few a couple of years ago ... never used them though... i buy too much parts...  : ...

 

[edanderson]

thomas,

the picture at tube amp doctor shows the same type of plastic package as the inductors that i use in the odd.  they are not originally intended as audio frequency inductors, and i had to go through a few different brands before i found ones that worked for me.  if these are spec-ed to work in the mesa circuit, then they probably will work in many other circuits, BUT you have to be careful not to saturate them with high level signals -- these inductors do not have a pleasant distortion characteristic to my ears.

ed

 

[hobiesound]

Thanks ed for the reply. Gotta love this place.

 

[hobiesound]

Ok i've got a few points i'd like to discuss. Here goes. Please i anyone could correct me if i'm wrong. I'm a total noob in this field and the algebra part of my brain doesn't function anymore since i left school ..... ok if i'm blowing smoke out of my ass please let me know....

higher perm cores saturate more easily. Right ?

Analag said high perm ferrite's suck and he prefered steel core inductors but aren't silicon steel cores designed to have higher perm also ? or does steel saturate differently if so why and how?

the bigger the core the higher the saturation sets in. Right? 

gapping a core helps to combat saturating the core with DC but does this matter in passive eq and swinging input eq's where DC blocking capacitors are used so no DC should flow thru the inductor?
or does gapping the core also help with respect of saturation from AC.

btw i ordered the smallest M-lam core's and bobbins from sauter. So i'll be winding some silicon steel inductors too. The lams are a probably a bit too thick (0.5 mm) for winding good audio transformers but i'm gonna try that too. If anyone knows a source for thinner lams for M42 cores or a source for smaller ei/m lams and bobbins (m30/ei30) and NiFe lams in SMALL quantities .... Sauter doesn't reply to my questions only to my order info (i even tried mailing in german) ...  i tried wescap in holland but i dont want to start my own winding company... haven't tried asking for samples though...

greetings,

Thomas

 

[Fablab]

But if I need a non standard value (ex. 13.8mH) what can I do?

 

[ChrioN]

You put them in serie. For example a 10mH and a 3.9mH. Or use 15mH and adjust the capacitor.