MSB power Dac gold 4

Hi , I have purchased a MSB dac IV gold from MSB with volume control , I am having an issue with my dac and have emailed them about the problem and they are thinking about it , I am wondering if any body has had the similar problem I am running the Dac from my qsonix music server into my sonic frontiers line 3 pre amp when listening at normal to slightly higher levels no problems but when turned to fairly loud the music breaks up (skips) maybe clipping ,back the volume off it stops ,I have tried to adjust the msb volume down but then have to turn the sonic froniers up . my amps are audio research 200 mono amps . any comments would be appreciated. thanks Bill