Grounding ?

---> Bob,
why relying on grounding through mass of interconnect cables is bad idea?

I have preamp and two monoblocks - all with unbalanced connection only. Ground is connected to the chassis internally. I have mains cord grounded only in preamplifier. Both monoblocks have lifted ground in power cords and are grounded through interconnects and preamplifier's power cord.
All hum disappeared and such connection seems to be safe (monoblocks are grounded through preamp). What is wrong in such approach?

Shock risk; possible inadequate wire size when ICs serve as ground; noise from having ground current flowing through ICs.

(1) If the amp should develop a problem that puts live AC on the chassis, the fault current will be flowing through the IC. Depending on the level of the fault, it may not be enough to trip a circuit breaker, but still be enough to electrocute you (all it takes to stop your heart is a few mA of current). You could be electrocuted from coming into contact with one end of an unplugged IC and chassis of the amp or other component connected to it.

(2) The shield/ground wire size in an IC may not be of a size adequate enough to carry full ground fault current, which can be greater than normal.

(3) Small ground currents flowing through ICs can create the very noise you're attempting to solve by lifting ground in the first place.

Thank you for the answer.
So, what is a solution?
Is the isolation transformers like Jensen Transformers are the only solution for full unbalanced system?
Honestly I do not know any person who use it.

Is a possible fix, and this is JUST a question, that 1 or more pieces has an internal hot/neutral swap?
Could you tell somehow? Maybe have all gear plugged into the wall without any I/Cs. Than measure for voltage between the chassis or ground of each piece? If there is a voltage between chassis of 2 pieces, isn't that a hot/ neutral swap?

Does everyone own an outlet tester? The type w/3 leds to indicate various good / bad conditions?