DAC Ground Plane Noise Reduction?

[fastcat95]

Hello to All!

I have heard of a product that plugs into something
like an RCA SPDIF input in a DAC, that uses some sort
of filter (connected to the ground only) to absorb the
digital noise in the ground plane system.

Does anyone know what sort of filter would absorb
the ground plane noise by being connected only to
the ground?

Thanks in advance!

Fastcat

[pku]

You only cut some PCB for a piece equal to DAC chip. Then pacth it on top of the chip. Soldering wire from this PCB to ground. It's easy way of making ground plane