@bifwynne The reason most companies don't provide EMI filtering is cost plus the fact so many engineers and managers just don't get the fact it isn't "just 60 Hz" coming out of the wall. If it was, there would be no need for any filtering or isolation. Consumers vote with their pocket book, so adding cost requires selling that added cost. One can prove it with graphs, data, independent testing labs, independent reviews, etc. but that doesn't mean the consumer will spring $$ for it.
Isolation is another animal. Every component we buy is already isolated from the wall via its internal transformer. However, that transformer is located inside the chassis so any leakage, stray magnetic fields, or EMI radiation will bleed into the unit. Yes, it can be done correctly, but again, it adds cost. The best solution is to put the isolation in an external chassis along with input EMI filtering. Since a separate chassis puts distance between it and the audio gear, the bleed energy is automatically reduced by the square of the distance between the components. That is hard to do when everything is in one chassis.
I design and build some of my own gear but frankly even in my stuff, the EMI filtering and isolation is in a separate chassis along with an external power supply for the audio unit.
Isolation is another animal. Every component we buy is already isolated from the wall via its internal transformer. However, that transformer is located inside the chassis so any leakage, stray magnetic fields, or EMI radiation will bleed into the unit. Yes, it can be done correctly, but again, it adds cost. The best solution is to put the isolation in an external chassis along with input EMI filtering. Since a separate chassis puts distance between it and the audio gear, the bleed energy is automatically reduced by the square of the distance between the components. That is hard to do when everything is in one chassis.
I design and build some of my own gear but frankly even in my stuff, the EMI filtering and isolation is in a separate chassis along with an external power supply for the audio unit.