Like @ghdprentice, I use long term listening sessions for evaluation, not A/B back and forth. Extended sessions give me chance to listen to a wide variety of music and get a good feel for it's strengths and weaknesses. Some things really start to stand out after a few days.
How do you A/B amps in your system?
Comparing two different amps in my system of separates requires changing speaker cable connections, inputs, and sometimes system volume. Do you have any tricks you use to simplicity the switch over and minimize time between hearing one then the other? I know audio reviewers make comparisons between amps, but for me there is more subjectivity at play than say comparing two input components. Is this just the nature of the beast, or do you veteran listeners have tips and tricks!?