Looking at the impedance curve for the CS2 measured by Stereophile I would’ve run the 8 ohm taps without thinking twice. The CS2 only hits a minimum of 6 ohms with a dip at about 170 hz whereas it’s at or above 8 ohms from 500 hz and up. Below 170 hz it fluxuates between 10 and 6.5 ohms. Surprised it has a 6 ohm rating to be honest.
If you’re having better results on the 4 ohm taps then it’s all good...enjoy the music.
If you’re having better results on the 4 ohm taps then it’s all good...enjoy the music.