Another thing that is well-known for causing listener fatigue is odd-ordered harmonics in trace amounts, something that is common to most transistor gear.
This will get more pronounced as volume is increased.
The reason is that the ear uses odd ordered harmonics to figure out how loud a sound is! If the equipment makes odd ordered harmonics it will come off as louder and brighter than the measurements would suggest.
Our ears are more sensitive to these harmonics than they are to human vocal frequencies- by quite a wide margin!
To get rid of the odd ordered harmonics, you might try introducing some tube electronics into the signal chain. Tubes are more linear, and make less odd ordered harmonics as a result. This is why they sound smoother in most cases.
This will get more pronounced as volume is increased.
The reason is that the ear uses odd ordered harmonics to figure out how loud a sound is! If the equipment makes odd ordered harmonics it will come off as louder and brighter than the measurements would suggest.
Our ears are more sensitive to these harmonics than they are to human vocal frequencies- by quite a wide margin!
To get rid of the odd ordered harmonics, you might try introducing some tube electronics into the signal chain. Tubes are more linear, and make less odd ordered harmonics as a result. This is why they sound smoother in most cases.