Hmm. I think the point of the AXE is to recreate the signature tones of other devices which are very colored, not neutral by any means and have a desirable coloration regarding their sound. IMH estimation, the AFX has a pretty neutral traditional audio "preamp" capability and extremely sophisticated audio processing technology. Their may be a signature tone or color to the axe fx "raw" hardware processing and amplifier sections, which actually should be a pretty simple test (TMA an AXE?). But I think the digital processing capabilities are sophisticated enough that they would overcome and essentially "difference-out" any colorations in the AXE system itself. (If you were to TMA an AXE, there are other significant considerations, such as cables, power supplies, external circuits, etc.) I'm not a philosopher, engineer, or theoretical physicist. Hell, I'm not even a musician. But in my opinion, the Axe can adapt itself to the point that it can practically hide it's own sonic coloration and therefore must be transparent. I believe it's that close to being right.