I use Cyrus amplification - an aCa7.5 and two SmartPowers, which are currently used in a bi-amping configuration as I prefer the sound to running them in mono mode. I read in an article somewhere that Cyrus only recommend using the SmartPower in mono mode when using a PSX-R as well. The pre-amplifier can also be used with a PSX-R. As there are plenty of PSX-Rs on Ebay, I thought I'd give them a go, but was wondering if anyone has similar equipment and could answer the following questions: 1. Where would the PSX-R make most difference? With the pre- or power-amplifiers? 2. What sort of difference does it make? The power of the SmartPowers increases with the PSX-R, so I'm guessing I might gain a little in weight or conviction, but I'm wondering how the pre-amp would benefit. Obviously I'm hoping that someone will say that the pre-amp gains most, so I can start by buying just one!