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Low/High-Pass Filter helps to remove noise
Posted: Sat Dec 02, 2017 11:46 pm
by tinkerBOY
Im testing a low/high-pass circuit I followed on
viewtopic.php?f=22&t=480 and noticed that it really helps a lot with cleaning the audio from a pi zero. I will be building my own pcb button board with builtin low/high-pass filter and amp pam8403 for now.
Im wondering what is the difference between this two:
link
- IMG_2440.PNG (15.91 KiB) Viewed 4031 times
- IMG_2439.PNG (34.28 KiB) Viewed 4031 times
Which one of these two circuit should i choose?
Re: Low/High-Pass Filter helps to remove noise
Posted: Sun Dec 03, 2017 3:45 am
by RetroRocket
I've used the bottom one that I believe was first posted by wermy. It works alright, but not as big of an effect as I was expecting. With PWM, even filtered it's acceptable but not great quality. Only difference I see with the top one is putting the cap after the ground filtering. I don't see a purpose for grounding the two audio channels separately, it's still two identical circuits with the same components. Maybe you could give both a try and get some tests done!
Actually, I'm finishing up two GBZ's this winter so I might try out the first diagram you posted to check against my own...
Re: Low/High-Pass Filter helps to remove noise
Posted: Tue Dec 05, 2017 2:13 am
by tinkerBOY
RetroRocket wrote: ↑Sun Dec 03, 2017 3:45 am
I've used the bottom one that I believe was first posted by wermy. It works alright, but not as big of an effect as I was expecting. With PWM, even filtered it's acceptable but not great quality. Only difference I see with the top one is putting the cap after the ground filtering. I don't see a purpose for grounding the two audio channels separately, it's still two identical circuits with the same components. Maybe you could give both a try and get some tests done!
Actually, I'm finishing up two GBZ's this winter so I might try out the first diagram you posted to check against my own...
Yes i used the bottom circuit too and works great for me.