Never lift the ground. Find the component that is causing the ground loop and either get it repaired (bad design) or replace it with something that actually is designed correctly.
It is quite simple to find out which component is causing the ground loop.
Connect only the amp to the speakers and turn the amp on. Noise? yes, it is either the speaker wires or the amp. No noise? then connect the pre-amp to the amp/speaker combination without inputs to the pre-amp.
Noise? yes? then it is either the pre-amp or the interconnect wires from the pre-amp to the amp.
Connect a source to the pre-amp with interconnects. Turn equipment on. Noise? yes/no? you see where I'm going with this?
poorly designed electrical equipment that have poorly designed grounding system are rare non-a-days, because designers have learned over the years. However, you might run into something that just has a bad ground design. Or, interconnect cables that are poorly designed.
Under no circumstance do you lift the ground on a piece of equipment. The ground is there for a very important reason and in the event of a fault, current will seek the easiest path to ground and you, your family, pets, etc. may become that path.
anyone telling you to lift the ground does not know what they are talking about. Find the faulty equipment and either fix it or replace it.
be safe and enjoy
It is quite simple to find out which component is causing the ground loop.
Connect only the amp to the speakers and turn the amp on. Noise? yes, it is either the speaker wires or the amp. No noise? then connect the pre-amp to the amp/speaker combination without inputs to the pre-amp.
Noise? yes? then it is either the pre-amp or the interconnect wires from the pre-amp to the amp.
Connect a source to the pre-amp with interconnects. Turn equipment on. Noise? yes/no? you see where I'm going with this?
poorly designed electrical equipment that have poorly designed grounding system are rare non-a-days, because designers have learned over the years. However, you might run into something that just has a bad ground design. Or, interconnect cables that are poorly designed.
Under no circumstance do you lift the ground on a piece of equipment. The ground is there for a very important reason and in the event of a fault, current will seek the easiest path to ground and you, your family, pets, etc. may become that path.
anyone telling you to lift the ground does not know what they are talking about. Find the faulty equipment and either fix it or replace it.
be safe and enjoy