Thanks for the response. Are you using tube or solid state equipment? I have spoke to Pierre at Mapleshade and he has been a great source of info however I still have the hum.I am using a Music Reference RM9 MK II and a ARC SP9 MKIII. The hum I am experiencing does not seem to be audible while listening. Still in the back of my mind is "how would it sound without the hum?" Again, thanks for the input.