I'm getting a small amount of background noise from my iPod through the FM Modulator I've fitted. Where would I put the noise suppressor, what type of suppressor should I get?
Thanks.

 

flyrr, from the sounds of things, your FM modulator needs a better filter in the circuitry. OR you are overloading the FM modulator with the output of your iPod.

As for installing a noise filter, it should be on the line feeding the component you want to filter. Most of the filters that you are going to find are nothing more than a small resistor and a capacitor. So, buy pretty much whatever you want. I have found that if you want to eliminate all the noise, then you are going to have to go with a voltage clipping type of unit. Not as efficient, but if you are looking for crystal clear sound, it is the only way to go.