Hi!
I happen to have some meters of 1.4mm cooper enamelled wire. I want to use a notch filter at 1kHz, and this asks for a 2.4mH. I thought about using a ferrite core (from a radio) and wind it myself. I know that this material will saturate easily at low frequencies, but I wonder if it will be ok at 1kHz.
Has anyone tried this before?
I happen to have some meters of 1.4mm cooper enamelled wire. I want to use a notch filter at 1kHz, and this asks for a 2.4mH. I thought about using a ferrite core (from a radio) and wind it myself. I know that this material will saturate easily at low frequencies, but I wonder if it will be ok at 1kHz.
Has anyone tried this before?
I expect little effect at all. You might end up with a coil similar to the core-less aircoils available on the market - something the size of a door-stopperb
Ferrites come in all shapes and sizes and more importantly different compositions, a ferrite rod from a A.M radio will use a ferrite material optimised for radio frequencies.
I've tried it & it works fine, but winding inductors is a PITA, I'd rather spend the $$ & buy them
Sure, you can use the ferrite to arrive at the desired inductance more quickly, or perhaps you can omit one if you have wire to spare, or combine it with a smaller diameter wire. Can you specify the entire notch?
edit: manually producing inductors can be a pain, or you can do something about it.
DIY Coil Winder
edit: manually producing inductors can be a pain, or you can do something about it.
DIY Coil Winder
air core 2.1mH: 585gr, 0.7 Ohm
iron core 2.2mH: 411gr, including ferrite, 0.49 Ohm
Both are diy, and I am no expert coil-builder.
The notch is for dampen the peak that appears in the mid-bass driver produced by the baffle step and the low pass filter. I learned that at troels gravesen site. (Thanks Troels!)
I suggest that you first draw a complete circuit into a simulator, then when you decide how much of input power you expect to draw from amplifier, you will be able to observe just how much will the notch participate in it.
Here is a measurement that I have made.
Saturated low pass inductor.
Here is a measurement that I have made.
Saturated low pass inductor.
Saturation is only an issue at very high levels, I find no problems at normal domestic listening levels
Hi Raka
Wasn't aware that you are still on this forum.
Is this for a parallel or series notch filter ? What are the values of the other parts of the filter ?
Regards
Charles
Wasn't aware that you are still on this forum.
Is this for a parallel or series notch filter ? What are the values of the other parts of the filter ?
Regards
Charles
You may use the coil's intrinsic series resistance as part of the 5.6 Ohms and go with a thinner wire if you like.
Regards
Charles
Regards
Charles