Phono Pre-amp Hum

I am also hearing a low level hum, but mine happens as soon as I connect any device. I've tried some of the fixs I've seen here: started by disconnecting the balanced inputs to the power amp (Threshold T-100) and there is no hum, so that means its not from the speakers.
Then I disconnected every component. As soon as I connect any device, (EAR 834P; tube CD plyer no matter what) I get the hum. I've tried cheater plugs, ground wires. Can't figure it out.
Any ideas?

I removed the ground wire that I had between my VPI Scoutmaster and the Linn Majik Kontrol (main) pre-amp and the humming sound is now gone!

Is there any harm in not having any ground to my analog set-up?

Well there can be a number of different reasons you get hum, and will take a little investigating but I can certainly help you. I have designed and setup some of the very finest in home audio video systems so I have alot of experiance in this area. Hum can be generated ether by the components themselves, or by ground loops. First thing I would try is unground everything. ((try ground cheater plugs that you can get at any hardware store first before permentally removing the ground prongs) Unless you live in a area were there are electrical storms or are worried that you might get shocked (to this day I have never heard of anyone being shocked by equipment)if that is a concern then I will give you additional suggestions on helping resolve this issue. If you unground everything and the hum goes away then you will know its not the component generating the noise. Try just grounding one component usually the preamp and see if them hum is still gone. Usually that resolves the issue.

Alittle info on what usually causes ground loops:

Most homes here in the states have 220 volts coming into our homes. At the electrical box, 220 is split 110 to the left and right side of your panel. The left and right side of the panel are 180 degrees out of phase with each other. If your listening room is using different outlets and are pulled from different sides of the panel they are out of phase with each other and will generate a hum. Important to make sure if you have dedicated lines make sure they are pulled from the same side of the panel.

The type of grounding is also important if your going to use them. In the many years Ive designed and setup systems I have not used grounds and have never had a single case of anyone getting hurt. If your uncomfortable ungrounding everything. then ground the preamp and with that everything would be grounded through the preamp.

I have had the best results by making sure the grounds are grounded to water pipes or copper rods driven into the ground at least 4 ft in a dry area.

Additional issues can be components to close to power supplys.

Some phono cartridges can also generate excessive hum on there own. Grados are notorious for having alittle hum on there own.

To much gain can be a issue try reducing gain to were your volume control tracks at a ideal level.

Hope that gives you some things to try and if you have any questions feel free to ask.

Kevin