Steel DAC chassis Shielding Question

[fastcat95]

Hello to All:

I have a DAC with a steel chassis, and the main board
is just 0.2" above the lower steel casing. I want to
add a 0.050" sheet damping treatment to the inside of the lower
steel case, and laminate a copper sheet above the damping,
which will then be between the damping and the circuit board.
I also want to ground the copper sheet to the AC third wire
in the system (the steel chassis is already grounded to the third
wire). Will this scheme be of any value in shielding the circuit board from interactions with the steel chassis plate? Any drawbacks?

Thanks in advance!

Dan

[Extreme_Boky]

Many CD players i modified have the case (chassis) connected to an analogue ground, but these units are not connected to the mains' ground!!!.... This depends on global grounding topology - in your case you have the unit which is grounded to the mains' ground. However, I am positive that the mains ground is a horrible and noisy potential, unless you have a separate ground feed just for Hi-Fi power outlet (like some "Hi-Enders").
The analogue signal ground should be the least noisy ground, so maybe you should try to connect your copper shielding to your analogue ground. I use copper shielding as well and I always connect it to a point where analogue RCA connecters are screwed to the back plate of the unit.

Regards,
Extreme_Boky