While I do totally agree with the NAD integrated amp suggestion, these A-S*01 Yamahas are really pretty solid performers even with nominal 6 and 8ohms speakers with occasional 4ohm dips. I know the all analog models(A-S1000, A-S2000, etc.) can handle these impedance dips very well.
As far as the impedance switch, my understanding is to leave at 8ohms 99% of the time.
Bill
As far as the impedance switch, my understanding is to leave at 8ohms 99% of the time.
Bill