The reason tubes are accused of being 'warm' is that they more closely follow the rules of human hearing than do transistors. If neutrality is your goal, and on top of that listenability, due to the constraints of the technology tubes are the only game in town.
Some important rules of human hearing are:
1)Loud sounds mask quiet sounds
2)loudness is detected by the level of odd-ordered harmonics
3)speed can invoke emotional response, slowness often invokes intellectual response
4)ears hear on a logarithmic scale, thus 'decibels'
5)bandwidth is roughly 20Hz to 20KHz.
6)sound location is detected by phase and time
a couple of examples:
Distortion masks detail, which is why SETs can sound more transparent and detailed than a transistor amp (if the speaker is efficient enough to take advantage of the low-power range of an SET).
Getting rid of negative feedback can reduce harshness (rule #2 above). Nelson Pass has shown this in his 'First Watt' amps, and tube guys have known this for a long time.
While no amplifier will ever be 'perfect', the more the rules of human hearing are obeyed the more the result will be an amplifier that is the most neutral while simultaneously being the most musical.
Some important rules of human hearing are:
1)Loud sounds mask quiet sounds
2)loudness is detected by the level of odd-ordered harmonics
3)speed can invoke emotional response, slowness often invokes intellectual response
4)ears hear on a logarithmic scale, thus 'decibels'
5)bandwidth is roughly 20Hz to 20KHz.
6)sound location is detected by phase and time
a couple of examples:
Distortion masks detail, which is why SETs can sound more transparent and detailed than a transistor amp (if the speaker is efficient enough to take advantage of the low-power range of an SET).
Getting rid of negative feedback can reduce harshness (rule #2 above). Nelson Pass has shown this in his 'First Watt' amps, and tube guys have known this for a long time.
While no amplifier will ever be 'perfect', the more the rules of human hearing are obeyed the more the result will be an amplifier that is the most neutral while simultaneously being the most musical.