The Phono input is dealing with extremely small signals ranging from a few hundred microvolts to a few hundred millivolts. Although this input is extremely well protected, it is sensitive to its environment. Make sure your Devialet has been upgraded to the very latest firmware and that all its inputs are well configured. Here below are the detail of the parameter to set into the configurator (setting of the Phono stage)
Note that the noise floor on the Phono input is higher than on other inputs.