It's always best to have a safety earth ground, especially on tube amps where there is high voltage present. If the ground-loop causes noise, this isolator usually solves the problem:\n\nhttp:\/\/www.empiricalaudio.com\/products\/final-drive\n\nI use them for my SET monoblocks that have 1000V on the output tubes. They also convert balanced to single-ended for me. No degradation in SQ, in fact they improve things quite a bit. Thanks to these, I don't have any ground-loops in my system.\n\nSteve N.