Sounds like power outlet,tubes or transformer noise by your description.Then again you might be hearing the difference in the preamp section's gain output relative to the amplifier's input sensitivity of the integrate.
In layman terms it's like having a preamp with too much gain for the amplifier.You get that background hiss in the music.With the volume turned all the way down it is very noticeable.
In layman terms it's like having a preamp with too much gain for the amplifier.You get that background hiss in the music.With the volume turned all the way down it is very noticeable.