Looking for an upsampler-which one?

I have a large cd collections played on a Classe transport and dac. I would like to try one of the new upsamplers. It seems that there are a number on the market and I have no local dealers. I have no interest at this time in SACD or DVD-A. I'm looking for an improvement in playback of cds not just a different sound. I understand that The Parts Connection has an unit that works quite well but haven't heard it. Any help would be appreciated.