Jim Lesurf wrote:

I was thinking of individual beads on each of the wires, followed (i.e. on
the DAC side) by an RF cap between the wires. Having just a series ferrite
increases the RF impedance and losses along the wiring, but that doesn't
always ensure good suppression. Indeed, might act as an antenna in some
situations. :-)

If the ferrite is something like a clip-on 'box' or a loop you can unthread
without damaging the wires it might be worth experimenting and seeing if
taking it off makes any difference. But if you aren't bothered by the
intereference I'd recomment not bothering if it would mean haveing to
rewire at all. If the interference is mains conveyed a filtered
distribution block will probably help, and will give you a mains switch if
you choose the right design. See something like the CPC catalogue for
examples.

I don't think I'm getting much interference, there is little or no hiss
from the DAC so I'll take your advice and not bother.
I will have a look at the CPC catalogue though, cheers.