Background noise with phono

  • Hello,
    I love the rkv mark 3 I own associated with a Grado PS100e.
    I listen two sources : a french streamer dac from Liedson and a Rega planar 3 with Goldring 1042 cartridge.

    The phono preamp within mark 3 sounds great, better than some other dedicated phono preamp I tried.

    But I have a problem bothering me : a background noise when phono source is selected.
    When the streamer source is selected it is silent.

    Rega turntables have the particularity to have no ground wire, I don't know if it is cause of the problem.
    With former amps I did not have the background noise problem.

    Is there a solution ? Any idea ?

    Kind regards.