Another grounding issue

[marcus7601]

I have done a lot of searching regarding the "proper" way to ground a gainclone-kit (3875) from Audiosector. However, i still didnt get a definitive answer. I use one transformer CT and one diode bridge.

Grounding points:
Rectifier (1)
Stereo volume pot (2)
RCA in (not insulated from chassi) (2)
amp-boards (2)
AC Safety earth (1)

How does the grounding-procedure change if connected to AC-outlet with no safety earth? (Even possible?)

Can someone help guy that eagerly tries to learn?

[AndrewT]

Hi,

Originally posted by marcus7601
I use one transformer CT and one diode bridge.

Grounding points:
Rectifier (1)
.............
RCA in (not insulated from chassi) (2)
............
AC Safety earth (1)

with a single rectifier and centre tapped transformer, none of the four rectifier connections go to ground.

The RCA must be isolated from the chassis.

The metal chassis must be connected to safety earth.

[marcus7601]

Ok, RCA in is now insulated.

So, if i get this correctly a star groundpoint is made on the chassie itself. One wire from each channel board (CHG) is connected here and from the star ground a wire to AC ground?

Does the volume pot need to be grounded and if so, also to the star ground?

[AndrewT]

Hi,
If you connect both channels to a common ground, then as soon as you connect a second input cable you will create a hum loop.