"Normal" at the Mains should be 125 to 130V average. You could have some voltage drop at your listening room outlets, depending on what else might be running off the same phase(high current draw appliances, HVAC, etc) at the time you measure, and the length/gauge of the wire leading to it from the breaker box. Mine measures 125V(mains and room), when the AC isn't running.
Input voltage and your poweramp
I have a pair of solid state mono block amps that's make excessive noise from their chassis. It's a loud buzz that develops to a rattle at times. Their tech is saying the problem is caused by the voltage level from, which fluctuates down to 116V. The utility company is telling me that the voltage is normal. For those here in the US, can you measure the voltage level at your socket? Thx.