I believe, Ralph of Atma-Sphere, recommends using a Zero device for low impedance speakers.Here is a link
http://www.atma-sphere.com/Support#FAQ
On the right hand side, he discusses what you are asking about. The Zero link is highlighted in blue.
http://www.atma-sphere.com/Support#FAQ
On the right hand side, he discusses what you are asking about. The Zero link is highlighted in blue.