Grounding options

[gimpchop]

Hi I've done lots of reading on this but cant find a definite answer. I'm building a chip amp based on the lm3886 I've been looking at different grounding options and cant decide. I know i need to earth from chassis to plug and to my transformer. I have got the neg from my center tap running through my bridge rectifier connecting my 10000uf caps. do all other neg i.e speaker rca inputs connect to this ground (star type) and then connect to chassis or do i keep them separate.? Also do i keep my neg from my amps seperate or do i include them in my star type grounding.? thanks

 

[scottjoplin]

Hi, have you read this? http://hifisonix.com/wordpress/wp-c...to-wire-up-a-Power-Amplifier-October-2017.pdf

 

[JonSnell Electronic]

The use of 'Star' grounding keeps loops to a minimum.
Use the connection at the 0v point on your smoothing capacitors as the return point for all grounds.
Earth the chassis on the chassis and use a 22R 1W resistor to connect the 0v point to earth.

 

[gimpchop]

The use of 'Star' grounding keeps loops to a minimum.
Use the connection at the 0v point on your smoothing capacitors as the return point for all grounds.
Earth the chassis on the chassis and use a 22R 1W resistor to connect the 0v point to earth.

hi thanks that seems to have helped a lot on my test setup especially with static when changing inputs(selector switch)
Does it have to be a 22ohm resistor as i have a 20ohm 1w no 22ohm 1w. thanks.

 

[00940]

Actually, the value doesn't matter much. But it's best to use a big diode bridge in // with that resistor. See those two good articles:

Power Supply Wiring Guidelines
Earthing (Grounding) Your Hi-Fi - Tricks and Techniques

 

[gimpchop]

great thanks for the help

 

[Speedskater]

.....................
Use the connection at the 0v point on your smoothing capacitors as the return point for all grounds.
Earth the chassis on the chassis and use a 22R 1W resistor to connect the 0v point to earth.

I would connect the AC power Safety Ground/Protective Earth to the chassis near where the power cord enters the chassis.
I would connect the power supply common and audio circuit common (aka ground) either directly or thru a resistor to the chassis near the audio input connectors.