The "Stereophile" review of the Yamaha AS-3200 pointed out that this very fine integrated amplifier should not be used with loudspeakers that present a load of 4 ohms or less. That makes me wonder about the loudspeakers that you are using. Otherwise, many other contributors have offered some good advice.
I hope you sort this out. The AS-3200 is a wonderful piece of hi-fi gear.