I think the concerns around "impedance mismatch" are somewhat exaggerated for most "typical component purchasers". By far, most of these purchasers either buy an integrated amplifier/receiver or solid state separates where the (separate) preamp almost always has an extremely low output impedance. Tube electronics, particularly separate tube preamps could pose some matching concern but those are usually purchased by more demanding, and sometimes more knowledgable customers.
Impedance match
My understanding for impedance matching a preamp or upstream source having a volume control (e.g., a DAC with volume control) to a downstream amplifier is that an appropriate “impedance match” is for the amplifier to have an input impedance at least 20-fold to 50-fold greater that the output impedance of the upstream preamp or source output impedance. One dealer told me that the appropriate “impedance match” between to such components is exactly that—an identical match of the same impedances.
So which is it?
So which is it?