![]() ![]() If I recall correctly, this does affect the 3W amplifier on the board, but again, the effect is lessened. If I connect a servo to the board, or dim an automotive LED driven by a 12V boost converter using PWM I also get varying amounts of static. The issue with the external amps is an extremely loud high pitched buzzing noise that increases in volume as more LEDs light up. Well, it may, but it's so quiet that it doesn't matter. The issue does not seem to affect the 3W amplifier I have integrated into the board itself. It happens with both the Lepai2020A+ and the DTA-2, both available on Parts Express. I assume the amplifier has sufficient filtering on its input. I don't know, nor do I know how to determine this. One is to filter the power supply better where it feeds the audio amp. Or are the audio input lines picking up emissions from the LED switching?ΔΆ different solutions. Is the noise coming in on the power supply lines? (You know, I'm still not clear on why this affects my amplifier when it is powered from the same battery, but not when the power source is separate.) PWM noise from some LED drivers is getting into my audio system. ![]() Oh, and yes, this is for filtering power. I have no idea if the values I am getting are sane, and I don't know whose advice to trust. ![]() That's way off from what DC42 suggested here: I have no idea what I should set the impedance to, but setting it to 1466 ohms gives me 330mH for the inductor, and 153.5nF for the two capacitors. That only calculates PI filters, not LC, and I find the fact that it accepts frequencies only in the MHz or GHz range suspicious, but it does seem to allow me to enter. I have tried adding all sorts of capacitors to remove the noise, and had only moderate success by adding several caps of different values (up to 4700uF), and I've read using inductors alone is no more effective at reducing noise. Is a first order filter one with just a capacitor or just an inductor? Wikipedia wasn't clear on that. (I had to check to make sure you didn't mean to write quadratic.) I don't know how to deal with imaginary numbers, and until today I'd never even heard of a quartic equation. I appreciate the help, but I don't understand a thing you just said. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |