Thanks for all the responses.I did upgrade my DAC in 2008,and I did get the Zanden cable connecting the DAC and transport repaired at Audio Revelation they did an excellent job.I also purchased from them a5J cable,that cable seems somewhat brighter than the Zanden cable,however it might not be completely broken in.As for repairing the DAC I decided to live with it as the hum is not noticeable at normal listening levels.
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