Baps, thanks for the quote from SAS. I am aware that changes in impedance will change the tonal balance of the system. What I unsuccessfully was trying to convey was my uncertainty about whether the 11A's impedance control adjuster affects the sound of the preamp beyond changing the output impedance, e.g. some people believe the addition of a balance control on a preamp adds a level of circuitry that diminishes the transparency of the component.
Again, I don't know the answer in the case of the 11A, but I like the idea of variable output impedance.
Again, I don't know the answer in the case of the 11A, but I like the idea of variable output impedance.