Fixed value inductors recommended for audio filter

[LazyTurtle]

Is there any brand that sells ferrite core inductors that can be used for audio purposes with good quality results?
I´m noyt into audio inductors so I´m totally lost on this.
I´ve seen several brands that can be bought in Mouser or Digikey, but really donñ´t know which ones can fit my purpose (inductor based audio filter).

Which parameters should I check to understand which one can fit an audio  project?

Any example of fixed SMD inductor for audio?

 

[volker]

http://www.audiomaintenance.com/acatalog/Inductors.html

 

[PRR]

> Which parameters should I check

Do you know how to calculate required inductance?

What if you needed 1 Kohm impedance at 1KHz? Do you know how to figure this is 160mH? (Check my math, I'm drugged today.)

"Audio" covers at least 20:1 range up and down around 1Kohm 1KHz, so you need other values.

You will find that 98% of the stock inductors are not enough H for many audio purposes. (There are a LOT more radios than audio-coil applications.)

Suppose you do find a 160mH coil but it has 1Kohm of Resistance. Then it is a pretty crappy inductor for 1KHz 1Kohm use, being half dead resistance.

 

[CJ]

start by stating what you want to build.

 

[LazyTurtle]

start by stating what you want to build.

I´m just looking for options to build a CLC high pass filter.
I´ve seen multitapped inductors for this type of project is a ferrite core inductor, with values from 700 mH down to 6 mH, but I suppose the values depend basically on the frequencies to be chosen for the filter...

I would like to know if using discrete inductors would be ok, and what type of inductors may fit this project. And if there´s any recommended brand or brands that can be easily found in Mouser/Digikey/Farnell etc...

 

[LazyTurtle]

http://www.audiomaintenance.com/acatalog/Inductors.html

Thank you, yes I know Audio Maintenance but the inductors are all multitapped, I´d like to know a brand that sells fixed value inductors and suitable for audio purposes.

 

[LazyTurtle]

> Which parameters should I check

Do you know how to calculate required inductance?

What if you needed 1 Kohm impedance at 1KHz? Do you know how to figure this is 160mH? (Check my math, I'm drugged today.)

"Audio" covers at least 20:1 range up and down around 1Kohm 1KHz, so you need other values.

You will find that 98% of the stock inductors are not enough H for many audio purposes. (There are a LOT more radios than audio-coil applications.)

Suppose you do find a 160mH coil but it has 1Kohm of Resistance. Then it is a pretty crappy inductor for 1KHz 1Kohm use, being half dead resistance.

Thank you for your answer.
I realize not only the inductance value is important but also the required impedance at a given frequency, and maybe other additional parameters.

I´ve always worked with inductors for DC/DC converters and RF filters, but for audio application I don´t know what other parameters parameters might be important.

 

[PRR]

> I´ve always worked with inductors for ....RF filters

Audio and RF, no difference.

Except values are thousands of times larger. In coils this means that DCR ("Q") may be hard to get.

And we don't often use C-L-C in audio because the input goes "short" above the passband. Even if you don't want that stuff, audio amps don't like shorts. Different in RF, especially narrowband RF where there shouldn't be large signal outside the passband.

 

[LazyTurtle]

> I´ve always worked with inductors for ....RF filters

Audio and RF, no difference.

Except values are thousands of times larger. In coils this means that DCR ("Q") may be hard to get.

And we don't often use C-L-C in audio because the input goes "short" above the passband. Even if you don't want that stuff, audio amps don't like shorts. Different in RF, especially narrowband RF where there shouldn't be large signal outside the passband.

Thanks a lot for your answer!
In my case the CLC filter type is due to a sonic characteristic that I want to be printed in the sound, nothing else.
I know there are better multiple filter topolgies, but in my case I need that one.

 

[ruffrecords]

I´m just looking for options to build a CLC high pass filter.
I´ve seen multitapped inductors for this type of project is a ferrite core inductor, with values from 700 mH down to 6 mH, but I suppose the values depend basically on the frequencies to be chosen for the filter...

I would like to know if using discrete inductors would be ok, and what type of inductors may fit this project. And if there´s any recommended brand or brands that can be easily found in Mouser/Digikey/Farnell etc...

Using discrete inductors will be OK but you will almost certainly need to use shielded types so that physically adjacent ones do not interact with each other and give unexpected inductance values due to coupling. I tend to use axial leaded power inductors - probably the sort you are already familiar with but they are increasingly hard to find in values greater than 10mH which is why you often have to string together a few in series. Unfortunately, the inductance value is dependent not only on the frequency you require but also on the characteristic impedance and a for this reason a CLC high pass filter tens to require large inductance values of the order on 1 Henry.

Sowter in the UK will make you a custom inductor of almost any value to order but they are not cheap. I do not know of any of the shelf supplier of single valued inductors in the 1H region.

Cheers

Ian

 

[LazyTurtle]

Using discrete inductors will be OK but you will almost certainly need to use shielded types so that physically adjacent ones do not interact with each other and give unexpected inductance values due to coupling. I tend to use axial leaded power inductors - probably the sort you are already familiar with but they are increasingly hard to find in values greater than 10mH which is why you often have to string together a few in series. Unfortunately, the inductance value is dependent not only on the frequency you require but also on the characteristic impedance and a for this reason a CLC high pass filter tens to require large inductance values of the order on 1 Henry.

Sowter in the UK will make you a custom inductor of almost any value to order but they are not cheap. I do not know of any of the shelf supplier of single valued inductors in the 1H region.

Cheers

Ian

Dear Ian, thankl you very much for the detailed information.
Yes, when doing the maths for low frequency (lets say 150Hz) and a 600Ohm impedance Z0 I get high inductance values...as the frequency rises, the inductance will be lower.

Regarding the "characteristic impedance" topic, are you referring to a specific impedance at a specific frequency?

Thanks

 

[LazyTurtle]

...I tend to use axial leaded power inductors...

So something like this would do the job? --> Fastron 11P-154J-50

Thanks