I have sold my phi 110 amp and am waiting on the phi beta integrated. I believe it is Kevin's best work to date. The sound is exceptional. I did own the phi 110 and the ren sig preamp. Call Kevin at VAC and let him walk you through the differences. I also borrowed a friends phi preamp to try with the phi 110. I have owned various VAC gear for the last 13 years. It is exceptionally musical, the service is terrific and the tubes last. The only reason I have ever sold a piece of VAC gear is to upgrade to other VAC equipment. I now listen with sonoran cable, sistrum racks and Caravelle speakers (which are some of the most musical, dynamic speakers I have heard). I have owned, Hales 5's, maggies, spendor and diapasons. You can not go wrong with VAC gear - very musical, dynamic, fast - 3 dimension of tubes with bass of solid state and frequency extention on top (not rolled off!). Enjoy. Email if you want to ask more questions.