I have owned both. You are lucky your JC1's have a sufficiently high input impedance so the Calypso's highish output impedance will not affect the sound. If it were me, purchasing for my system, I would purchase the VTL on sound quality alone. However, there are a few differences. The VTL is better on tubes and sounds smoother with a very clear and nicely extended high end. The Calypso may have a bit tighter bass and is fully balanced in and out, where the VTL is not balanced and only has balanced outputs. The midrange of the VTL approaches the classic tube sound where the Calypso's midrange is dryer. They are both reasonably extended for tubed units. Some to most might like the Calypso's styling better, but hopefully you have seen both. You may want to get the SN of the VTL unit you are interested in and call VTL because there have been updates, and not all the older units can be fully updated to the latest spec, if that is important to you. I have tried a whole bunch of tubed preamps and I could live with the VTL, but not with the Calypso. However, that is just me and my system, and you should probably listen to both if possible. Good luck.
VTL 5.5 or Aesthetix Calypso
I am considering one of these two preamps to match up with Parasound JC1s and Magnepan 3.5s. Has anyone had a chance to hear the two? I am leaning toward the VTL as it cost less but could spend the extra $$ if the Calypso is that much better.