I personally use a Hiraga pre pre borrowed by a skilled audiophile,but you may found something interesting on Salvatore site.
http://www.high-endaudio.com/RC-Step-ups.html.
I know one man quite satisfied with the concordant one on a high end system.
http://www.high-endaudio.com/RC-Step-ups.html.
I know one man quite satisfied with the concordant one on a high end system.