I was looking to buy the Yamaha RXV-2400. Before buying I downloaded the manual. Instead of having a 4/8 ohm switch, it was labeled 6/8 ohm. Since my speakers were 4 ohm, I e-mailed Yamaha. The reply I got was that they would not recommend anything lower than 6 ohms for their new amps. They said they would work with 4 ohm speakers but overheating might be a problem. Not a ringing endorsement.