Can't speak for the parent, obviously, but mine is constant, although at times peaking a bit too much for comfort. Impervious to anything I've thrown at it over

Can't speak for the parent, obviously, but mine is constant, although at times peaking a bit too much for comfort. Impervious to anything I've thrown at it over the years. You sort of get used to the damn thing, but you never loose awareness of it. Those more or less sinusoidal 8 kHz have been droning in my right ear for about a decade now.