Effects of no ground in wall outlet

I bought a 50 year old house last year. The inspector told me that all but one outlet was wired incorrectly, in that there was no ground between the outlets and the circuit breaker box. How will that affect my hi-fi? I'm planning on buying a McIntosh MC352 amp and am concerned that this may keep the amp from performing well. I'm planning on getting an electrician out to the house pronto.