So is the convention that an AMP must have an in input impedance 10 times higher than the output impedance of the DAC that is connected to it TRUE? The published specs over on MASSDROP of the ONE LINEAR AMP show an input impedance of 1k ohm. Problem is that my iDSD BL has it's DAC's output impedance as 240 ohms. So 10X that would be 2.4k ohms which breaks the rule of optimal impedance matching? Will this create audible distortion or something? Similarly, I was considering buying an SU-9 DAC which is 122 ohms but still an impedance mismatch. What is weird is that the Drop THX789 amp shows input impedance of 50k ohms balanced or unbalanced. You would think that the ONE LINEAR AMP, which was supposed to be a single-ended version of the THX 789 would have similar specs for input impedance? So I guess my question for those more technically minded is: "What will be the outcome of this impedance mismatch?" and "Will it be audible?"