Let's start immediately by saying that an isolation transformer is indispensable if high-efficiency and sensitivity loudspeakers and amplifiers with high power and dynamics are used in your HiFi system.
It is therefore essential to "isolate yourself" from your home network as the various appliances, TV, PC, lights, etc. create interference that is reproduced by your system.
Clearly all this does not necessarily mean spending thousands of euros, but only studying in detail, based on the absorption power of your amplifiers and electronic accessories, the size of the transformer to be inserted at the head of your system.
Attention, isolating your network does not mean filtering it, it only means interposing an autonomous secondary level which does not reflect the various interferences from foreign devices.
AudioLai uses toroidal isolation transformers of different sizes according to the type of absorption of the complete system, leaving an "ease" of 80% with respect to real consumption.
The importance of isolating the network is well known to all those who use drivers with very high sensitivity, usually above 100db, sometimes just turning on a light bulb nearby can generate audible interference even by those with an inexperienced ear.
In addition to the isolation transformer it is also essential to use good power cables, the cable that carries the power supply to the amplifier must be well shielded and if there are more than one they must be well spaced or intertwined.