Hi Bill,
I read the article that you provided a link to.
Its a pretty old article that you have referred to and amplifiers have come a long way since it was written.
I do personally believe that the most important component in a system is the speaker and if I upgrade other parts of my system I usually only hear minor improvements. In my experience the next is the amplifier.
I currently have five amplifiers that I have collected over the years and unfortunately I find it difficult to off load them. I bought my first amplifier over 20 years ago and it was a NAD 3240PE and the amplifiers that I have now are far superior imo.
I'm sure that a good qualifity audiophile speaker, like SP TECH, would make it pretty easy to hear differences in amplifiers. It is subtle but when you've had as many amplifiers in your system you find out thru trial and error what type of sound you like.
Thanks for the information and I agree it is a lot harder to pick cables than amplifiers

.
Regards
Rod