I can't think of any reason that the balanced attenuators would sound better, or even different. What will make a difference though is the amount of attenuation that they will provide. 10db attenuators are common (and the ones that I have used) but that might not be enough. You can also get them in 20db and perhaps anything in between. FWIW Rothwell makes a nice in-line attenuator. If the hiss is really loud I'd try the 20db ones first.