Porscheracer, some people have reported that using Rothwell attenuators has resulted in adverse sonic effects such as a reduction in perceived dynamics. Others have reported excellent results with them. I am in the latter group, having used the unbalanced 10 db version for several years, a few years ago. (My present system configuration doesn't require them).
I suspect that a major factor in the disparities among these reports is the impedances of the components they are being used with. The worst case scenario figures to be an output impedance of the component providing the signal to them that is high and also varies significantly as a function of frequency, together with an input impedance of the component they are providing a signal to that is low.
Regards,
-- Al
P.S: David_Ten, thanks for the nice comment.