How to choose appropriate transformer

[davelectronic]

Filter circuit

There are many types of filter cicuits, yours is audio, you need it to filter a certain frequiecy out put, but not deteriarate the audio quality, best to google audio filter circuits. its not possible to give a schematic for a circuit with out knowing output frequency in the audio circuit, i would google and look for a similar filter, audio sites might give some ideas, eaither inductor/resistance, capacitor/ resistance. as i say loads of filter cicuits, depends on application, and your circuit parameters.

 

[vinod chandran]

Hi Dave,
I got a passive filter circuit and i built it today. The circuit filters the frequency ranges above the 150Hz. For your information, i am attaching the image here. plz take a look. I connect that filter to an old 40W mono amp(ic 4440). Its working but i am not very happy with that bass sound. In the circuit, the author told that the frequency can be adjusted with 2k2 potentiometer from 50 Hz to 160 Hz. but i used a 10k pot. is that a problem?. anyway i am expecting some helpful advices.
-vinod

 

[(*steve*)]

That circuit is 99% attenuator, and 1% filter.

The response is going to vary a lot depending on the input impedance of the amplifier which follows it.

It also looks like you've incorrectly redrawn this circuit.

And are you driving it from the speaker outputs? and does the amplifier you are using have a similar input impedance to the one suggested in the article?

 

[vinod chandran]

Hi steve,
You are right. that circuit is worng. but the reason is, i don't know about that type of pot conection. And i am driving this in between my fm radio board and 40w mono amplifier(ic 4440). I am going to reconnect this as you said. I don't know what is my subwoofers input resistence. Anyway thanks for your advice.
-vinod