Headphone amp noise

[if...]

I have a Musical Fidelity V90 headphone amp connected to a V90 DAC. When I switch them on I hear "noise" through the headphones (NAD Viso) which is very noticeable. It fades into the background when music is playing, but is very annoying during quiet moments in music! Is this something I have to live with or is something wrong?

 

[dalethorn]

I have a Musical Fidelity V90 headphone amp connected to a V90 DAC. When I switch them on I hear "noise" through the headphones (NAD Viso) which is very noticeable. It fades into the background when music is playing, but is very annoying during quiet moments in music! Is this something I have to live with or is something wrong?

Something is wrong. First, try to determine if there's a lower "gain" setting that would reduce the noise, then see if you can maybe reduce the AC mains noise with an isolater or filter of some kind.