How many are using Amp to CD with variable...

I am using passive preamp in my system, works very well. There was just a thread on this in the last few days "Why do preamps improve sound of CDP?" It is a matter of taste and system.

I've tried running my Audio Aero Capitole CDP direct thru my Plinius SA-102... however, I found the sound to be significantly better when run thru my Calypso preamp.

I do. I use a Wadia CD player with "volume control" and adjustable output levels and plug directly into an amp. Wadia recommends this, an I concur that it results in more detail and less haze in the music. I.E. better. I use a SS Amp from Classe and have not had a problem. I tried this with a tube amp (ARC VT100) and I think the amp ran hotter. I don't know if the VT100 is an imped. mismatch or what or something to do with the balance XLR pins. i was only doing this with XLRs, because I need real long cables and have tons of XLR stuff.