Thanks for your responses everyone. I am very grateful, I realise that this is truly a great hobby. I have printed all your responses to my questions regarding the problem hum I am experiencing and reading them carefully. I am going to plug my solidstate (ss) system to do some testing. I don't want to do this on my tube equipment for fear of damaging them as I would have to switch on/off many times to try some of the suggestions. Sol322, the dedicated line was installed by a professional. Pending the outcome of the ss test, I will get him back for any other required adjustments, as this is definitely NOT my area of expertise. Here are more details on how I connected my equipment. TO DEDICATED LINE- 2 scenarios that caused the hum to occur 1) ALL equipment through a power conditioner to one outlet 2) ALL equipment directly to the newly installed dedicated outlets. I have pre/power/CD so I used only 3 outlets. TO COMMON LINE- Same connection as above scenarios but this time to common outlets. Note my common line has no ground connection. Result is NO HJM! I will post ss results, sometime tomorrow, July 11. Many thanks again to all. Best regards.