Shouldn't amp reviews employ multiple speakers?

Well -- all the reviewers I know buy their own gear, plus many of them are married and their spouses may not like to see three pairs of different types of speakers in the listening room.

Personally, I have two 2-channel systems set up in two different rooms with different components and when I think there may be an equipment bias issue, I sometimes put the review component into each system to see how the results compare. Not all reviewers have that luxury, however.

As Aball notes, there are just too many combinations of components, wires, and speakers for any reviewer to try them all. We do the best we can with the gear that is available to us.

And I notice that Aball himself has done three amp reviews here, for Audiogon, and it appears that he used those amps with only one set of speakers. Whadayaknow!

Gs5556 makes some good points. I have one of my systems set up to be as revealing as possible for testing electronics. You really need a linear, low-distortion, wide-range system to hear what electronic components are doing (or not doing). I mean, you can't comment on dynamic contrasts if your system is dynamically constricted, and you can't comment on bass quality or treble quality if your system does not have adequate resolution at the frequency extremes, and so forth.

Lots of folks don't even know what their amps really sound like because there are so many other limiting factors in their chain of components...