Neutral amp parameters

The aim is to collect all known public results of different truly-blinded tests concerning sonic perception. As a result of such integration I'd like to see a list of parameters/demands for "perfect neutral amplifier" (my hope is, all colouration-aware debates will be beyond the thread. Truly neutral amp is the aim).

Among common parameters some other are in interest too, for example:

- infra-low (till 0Hz) and ultra-high frequencies inside amp BW,
- thermal (memory) distortions,
- harmoincs (each harmonic individual level, i.e. harmonics dustribution) dependency on SPL, or...
- masking effects (lower harmonics are masked with audio signal, higher harmonics are masked with lower harmonics, ... what else?),
- ... ?

Please, give refs to public available resources only!
 
I think it is hard to tell neutral amp from not neutral.
How should one know that the amplifier is neutal?
There is no pattern, no template of perfect neutrality, only comparison tests. For lo-fi you just compare with better eqipment to judge if something's more or less. neutral.
It is a bit like search for most typical man in the world :)
 
darkfenriz said:
I think it is hard to tell neutral amp from not neutral.
How should one know that the amplifier is neutal?
There are plenty audio perception measurements in audology. It is possible to define different "ear thresholds". But I have not found such results concerning amps designing.

Saying "neutral" I mean very simple thing: audible or not. Above or below different thresholds.

For example (as for thermal distortions): "result of these tests is: CC beoynd NFB loop, 2SA1045 is in use, power deviation must be <= 1mW".