I honestly was expecting a distinct difference here. Nope, the cheap sony shelf system as the source amplifier sounded the same as my reciever. Now, there were differences. The Sony did have a higher noise floor, as it is very low power and I had to put the volume up around 8 out of 10 to get normal listening levels with a cd with high dynamic range (a telarc sampler cd). Otherwise I *thought* it sounded like there was more distortion, I cannot measure it, so I am guessing its just my imagination. The music also does get compressed on loud passages, but that is because the amplifier is probably only rated at 2w per channel - at 4ohms even, my speakers have an 8ohm impedence. What does this mean? It can mean two things. Either I have extremely poor hearing, or as long as an amplifier is working within its linear region, they will all sound the same. Strange, I have heard that amplifiers all sound the same somewhere else.... I belive my hearing isnt that bad, so I believe that they are the same. Why should someone spend more on an expensive amplifier then? Well, 1w of power isnt exactly a lot. To put output in decent levels, the volume control had to be turned completely to the maximum. The noise floor was rather high too at this level. If all you need is 1w of power output, this cheap little thing would probably work just fine for you! Dont worry, I hold myself to the same standards as everyone else. Tonight, I will have someone switch between the two sources and I will see if I can pick the right one out. I will then update you all, seeing if I can.