Dr Floyd Toole mentions in his book in passing that electronics do NOT impart a sonic signature. He's been at this game a lot longer than anyone and would know. You being a research engineer and logically speaking, should know that imparting a manufacturer's house sound would contradict what amplifiers have been designed to do, amplify cleanly without skewing the signal towards a house sound. Another word of caution is putting belief in what the marketing department says. The markerting department regardless of vendor is designed to do one thing, SELL. And marketing departments will use pseudo science, misappropriate and miss use engineering terms, basically lie to sell their products. And why is that? Because they know there are gullable audiophiles just waiting to eat up the jargon and spend their money. Pogre hit the nail on the head stating that everytime you challenge an audiophile to a controlled blind listening test, they pass.\n\nWhat kind of equipment did you test and what was the protocol used around the tests?\n\nYou wrote this as I was about to leave anyway it is my pleasure to respond to this before leaving. Sure I agree with all that, but in the practicality of all things. It is dependent on the manufacture process of the underlying components and the materials used. Different environments incorporate a variation of their protocols to manufacture components. Every batch may suffer differences. Beginning of the run and end of the run produce products with varying specifications. Quality control depends on this, too. This is why no two devices may share the same signature and need to be tuned. The reason some with the identical device is having issues with their unit and some may not. It is not proper for me to disclose certain aspects of my past employment due to "Disclosure" However, I do respect everyone's opinion and their right to believe as they do. I have mine and you have yours. Thus, we may agree to disagree. Goodnight.