Do you consider any of your amplifiers to be neutral? If so, what do you mean by that and how do you know it?
I have written many times that I think audiophiles use "colored" as a "general purpose slur" against whatever components of which they don't like the sound. We do know what each other means subjectively when we use the word, but I don't think there's any objective integrity underpinning the adjective. A solid-state amplifier fan will typically disparage a low power SET amplifier as "colored."
I think the whole audiophile concept of "neutral" is specious, because there is no objective, mutually agreed starting point.
Someone who adopts Objective 2) "reproduce exactly what is on the tape, vinyl or digital source being played," is likely to find Boulder electronics to be "neutral" and Kondo electronics to be "colored." Someone who adopts Objective 4) "create a sound that seems live," may find Boulder electronics to be "colored" and Kondo electronics to be "neutral." Both assessments derive from nothing more than the personal subjective preferences of the audiophiles.
As is often the case in this hobby we are back to the incomparability of interpersonal utility and the immutable reality that most of this hobby is subjective. Many audiophiles attempt to clothe their personal subjective preferences with a veneer of objectivity to justify intellectually their purchasing decisions, but I think it is invalid.
My analytical framework is audiophiles:
1) consciously or subconsciously select a high-end audio objective
2) evaluate components according to the selected objective
3) assemble systems which they believe satisfy the objective
4) criticize components which they believe do not satisfy their selected objective*
*And almost all of the on-line fencing derives from not understanding that they selected different objectives at the outset.