Author Topic: Is a built in mains hum noise filter needed?  (Read 881 times)

xorophone

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Is a built in mains hum noise filter needed?
« on: July 31, 2016, 03:13:48 PM »
Hello! I'm building the Leviathan delay from Etcher's Paradise on a perfboard for someone I know. Does this schematic have built in noise filter for the power supply? I've watched "DIY Guitar Pedals" video on youtube on how to reduce mains hum (
) and I was thinking it might be a good idea to add one to every pedal I make, but if it already has one it's of course unnecessary. I can't really tell the voltage bias and filter circuitry apart on this schematic. If I do add one, I should place it after the 1n5817 diode, right?

Thanks!

m-Kresol

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Re: Is a built in mains hum noise filter needed?
« Reply #1 on: August 01, 2016, 01:14:09 AM »
C27 and C28 are for power filtering/smoothing ripple current from the supply. C29 does the same for the reference voltage Vb after the voltage divider formed by the two resistors R24 and R25.
in general, capacitors (usually larger capacitance values) going from DC voltage to GND are for that. You'll find them in almost all projects around here. Kind of standard.
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xorophone

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Re: Is a built in mains hum noise filter needed?
« Reply #2 on: August 01, 2016, 09:09:38 AM »
C27 and C28 are for power filtering/smoothing ripple current from the supply. C29 does the same for the reference voltage Vb after the voltage divider formed by the two resistors R24 and R25.
in general, capacitors (usually larger capacitance values) going from DC voltage to GND are for that. You'll find them in almost all projects around here. Kind of standard.

Thanks! I'll skip it then. :)

Edit: Thanks for the explanation by the way. I'll probably be able to identify them myself in the future.
« Last Edit: August 01, 2016, 09:11:42 AM by xorophone »