Just picked up an old Yamaha A-460 integrated amplifier for the amazing price of free! It was well kept - original packaging and manual. The specs say 35W/channel @ 8 ohms.
Under Connecting the Speakers it states,
So, it can run a pair of 4 ohm speakers, but should I?The matching impedance of this amplifier is 8 ohms. Either one or two pairs of speakers may be connected. If only one pair is connected the recommended speaker impedance may be anywhere between 4 and 16 ohms. If two pairs are connected, however, it is advisable to use speakers with at least an 8 ohm impedance for optimum performance. Connecting two pair of 4 ohms speakers is not recommended.