I acknowledge your opinion. However, we have found with extensive R&D that our amplifier connected to Genesis 350se speakers is much more musical, and detailed with higher input impedances. Looking into that further, we have connected pre-amplifiers to the Audio Precision, and found that the frequency response of the pre-amp doesn’t remain the same under load, it becomes rolled off.
Pre-amps are voltage amplifiers, not current amplifiers. Voltage amplifiers are not designed to power low impedance loads. Not to say that they won’t, but that it will change the musical characteristics.
You can see that even power amplifiers have different frequency responses based on loading. If this is happening to something that is made to power heavy loads, you can bet that source equipment will do the same, but in a more extreme manner. The easier the amplifier is to drive, the closer you can obtain input to output similarities in sound. Any amplifier, which can be pre-amp or power amp, will be affected by the amount of loading.