Low/High-Pass Filter helps to remove noise

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tinkerBOY
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Low/High-Pass Filter helps to remove noise

Post by tinkerBOY » Sat Dec 02, 2017 11:46 pm

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
Circuit 1Show
IMG_2440.PNG
IMG_2440.PNG (15.91 KiB) Viewed 1446 times


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Circuit 2Show
IMG_2439.PNG
IMG_2439.PNG (34.28 KiB) Viewed 1446 times
Which one of these two circuit should i choose?
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Re: Low/High-Pass Filter helps to remove noise

Post by RetroRocket » 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...
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Re: Low/High-Pass Filter helps to remove noise

Post by tinkerBOY » Tue Dec 05, 2017 2:13 am

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.
New! tinkerBOY PowerSwitch v1.0 with Safe Shutdown
Game Boy Zero Controllers available @ tinkerBOY.xyz * Support
tinkerBOY Controller v3.0 - built-in usb controller, usb audio, and usb hub
tinkerBOY Controller v2.0 - GPIO buttons and builtin PWM Audio and Amplifier
tinkerBOY Controller v1.1 - simple pcb button
* DPI Adapter - better display for GBZ
* keyboard converters - IBM XT/AT Soarer's Converter | ADB to USB Converter

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