how can a line cord affect frequency response ?

Robert,

Always glad to hear your thoughts on the subject. Based on our previous discussions, I also suspect a device like the Z-der block, in conjunction with a properly designed power cord, provides an even greater capability for a components power supply to operate optimally. I know mine has performed nicely on my preamp with a Virtual Dynamics Nite II, and now a Virtual Dynamics Master power cord plugged into it.

BTW - the Volume II sampler is wonderful. Thanks so much.

While this may not answer your question, if you are looking for some type of guide as to the sonic signature of various brands of PCs, this thread by Audiogon member Tvad may be of interest to you:

http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1126482002