My experience is opposite the above post regarding bass response. The Phi 110 I once owned had the most incredible bass response of any amp I've owned including solid state amps. On that amp I did find the top end too soft resulting in a somewhat distant perspective. The PA100 is my resident amp and I don't find it overly spacious, lacking bass, or top end. However, the bass is not close to that of the Phi 110. My PA100 amp has shown the door to all challengers so far. I've considered the upgrade to the Phi input circuitry but I have not heard the Phi 200 to know if I would like the change.
