Something not mentioned is the sonic issues related to lifting a ground.
The problem is a ground loop, you lift the ground and no more hum. This is caused by the fact that some part of the signal chain (amp, preamp) is improperly wired.
For example if the chassis and circuit ground are the same thing, that unit will be prone to ground loop issues. Now to pass UL and CE (in fact any electrical code worldwide) the chassis has to be grounded. The issue is how to deal with the circuit ground if the chassis is grounded, and not have a ground loop.
The solution is simple but you would be utterly amazed at how many companies have not sorted this out! All that is needed is the circuit ground 'float' within the chassis, with all ground points like RCA connectors and the like isolated from the chassis. Then a moderate resistance is used between the chassis and circuit ground. This floats the circuit ground at chassis potential (electrical ground).
The added benefit is that now the chassis shields the circuit without injecting noise, something that results in better sound due to 'blacker backgrounds'.
So, IMO/IME its worth it to get equipment with bugs like this fixed! If done, you never worry about grounds again, and you don't have to mess with exotic (kooky) grounding schemes like a rod in the garden or some messed up stuff that is a recipe for trouble.
I know that may draw some criticism but honestly, get the equipment fixed and you will find out what I am talking about.
The problem is a ground loop, you lift the ground and no more hum. This is caused by the fact that some part of the signal chain (amp, preamp) is improperly wired.
For example if the chassis and circuit ground are the same thing, that unit will be prone to ground loop issues. Now to pass UL and CE (in fact any electrical code worldwide) the chassis has to be grounded. The issue is how to deal with the circuit ground if the chassis is grounded, and not have a ground loop.
The solution is simple but you would be utterly amazed at how many companies have not sorted this out! All that is needed is the circuit ground 'float' within the chassis, with all ground points like RCA connectors and the like isolated from the chassis. Then a moderate resistance is used between the chassis and circuit ground. This floats the circuit ground at chassis potential (electrical ground).
The added benefit is that now the chassis shields the circuit without injecting noise, something that results in better sound due to 'blacker backgrounds'.
So, IMO/IME its worth it to get equipment with bugs like this fixed! If done, you never worry about grounds again, and you don't have to mess with exotic (kooky) grounding schemes like a rod in the garden or some messed up stuff that is a recipe for trouble.
I know that may draw some criticism but honestly, get the equipment fixed and you will find out what I am talking about.