Impedance mismatch can be tough to identify unless you know what a good match sounds like. I mean absolutely no disrespect to Missioncoonery when I say this.
I didn't understand what impedance mismatch sounded like until the past year, and honestly, now I understand why some of the combinations I tried over the years were better than others. In my system, a god impedance match results in deep, well defined bass, and a sound that is not tipped up. A bad match has bass that sounds a bit muddy and ill defined, and sometimes has slightly less volume than the mids and highs, which results in a "bright" sound.
Don't take my word for it. Read John Atkinson's test measurements section of the Stereophile Calypso review. He clearly states the issue, and he mentions what the minimum input impedance that any amplifier should have if used with the Calypso.
I didn't understand what impedance mismatch sounded like until the past year, and honestly, now I understand why some of the combinations I tried over the years were better than others. In my system, a god impedance match results in deep, well defined bass, and a sound that is not tipped up. A bad match has bass that sounds a bit muddy and ill defined, and sometimes has slightly less volume than the mids and highs, which results in a "bright" sound.
Don't take my word for it. Read John Atkinson's test measurements section of the Stereophile Calypso review. He clearly states the issue, and he mentions what the minimum input impedance that any amplifier should have if used with the Calypso.