<font color='#000000'>My theory is this, when making a recording, the artist may choose tube mics/amps because they like the distortion profile that colors the voice/guitar sound. Great no problem there. I also like how a tube amp distorts guitar.
However, the playback of the recording should be as faithful as possible. Thus throwing another tube amp into the mix at the playback stage can only further colorize the sound which may not be the representation of what the artist intended.</font>