Alan Shaw never said that all amplifiers sound the same. Amplifiers can sound different for a number of reasons. The first is if the input sensitivity is too high, as is all too often the case. This may sound impressive, but what you are hearing is clipping and the concomitant compression. The second potential problem is insufficient power. The requirements can vary enormously depending on room size, speaker efficiency and music type. However, more is always better. Alan Shaw recently demonstrated the M40.1s in Hilversum in the Netherlands (there is a Youtube video somewhere on the web) and the amplifier had big digital power meters so one could see what it was being asked to deliver: at times more than 500 watts.
The third problem is a load dependent frequency response. Stereophile has these very useful graphs of frequency response under simulated real conditions, and the results are sometimes really bad, especially with tube amplifiers. Here solid state is clearly better and often by a wide margin, but tubes are not the only dispointing amps. Some boutique solid state amps can be almost as bad. This matters, because any deviation of more than 0.2 dB is audible. The solution is a powerful amplifier with a beefy (and hence expensive) power supply. In the absence of proper measurements, you could select your amplifier by weight. The good news is that mainstream Japanese manufacturers all have this under control. If you are looking for big power of high quality, there is little to beat a pro audio amplifier like the 2x250 watt Yamaha p2500s that I recently gave to my son (for use with a Harbeth M30.1), or its bigger family members. The 2x350 watt P3500s was tested (i.e. mesured on an Audi Precision test bench) in a French publication and it was as perfect as could be, and better than many audiophile amps.
As a pre amplifier you could go for a DAC with multiple inputs and variable output (including XLR) like the Pioneer U-05.
The third problem is a load dependent frequency response. Stereophile has these very useful graphs of frequency response under simulated real conditions, and the results are sometimes really bad, especially with tube amplifiers. Here solid state is clearly better and often by a wide margin, but tubes are not the only dispointing amps. Some boutique solid state amps can be almost as bad. This matters, because any deviation of more than 0.2 dB is audible. The solution is a powerful amplifier with a beefy (and hence expensive) power supply. In the absence of proper measurements, you could select your amplifier by weight. The good news is that mainstream Japanese manufacturers all have this under control. If you are looking for big power of high quality, there is little to beat a pro audio amplifier like the 2x250 watt Yamaha p2500s that I recently gave to my son (for use with a Harbeth M30.1), or its bigger family members. The 2x350 watt P3500s was tested (i.e. mesured on an Audi Precision test bench) in a French publication and it was as perfect as could be, and better than many audiophile amps.
As a pre amplifier you could go for a DAC with multiple inputs and variable output (including XLR) like the Pioneer U-05.