While I realize that this thread hasn't been responded to in a few months, I did want to relate my own experiences here...
I am 61 years old and have been purchasing, listening to and enjoying audio equipment all my life. Not that this makes me any kind of expert, just providing a little background.
I had been using a Denon 130wpc receiver to drive a pair of $800 Paradigm booshelf speakers and a JBL subwoofer when I decided to upgrade my system into something of an audiophile system. The very first thing I did was purchase a pair of B&W 600 series speakers. As I listened through the weeks, I noticed that the high frequency sounds all sounded a bit harsh, fake, irritating in a way. So, I looked into going to a new amp, all set to purchase a Rotel integrated amp which I thought would help.
What ended up happening, is that I compared the Rotel to a Macintosh integrated (MA-6300) and immediately noticed that the Rotel really didn't seem to sound much different than the Denon that I had been using. The McIntosh on the other hand seemed to treat the highs much better. They sounded smoother, more natual. Still not great but better.
Well fast forward a few months an I saw a deal that I just could not refuse. A pair of B&W 802D speakers for $9000. I bought them and to this day still use them with the MA-6300. Am I totally satisfied? No I am not as the MA-6300 STILL sounds to me a little strange in the high areas. Doing so research in during the next few weeks, I noticed a common complaint about the MA-6300 in that it tends to have slightly harsh highs. Ummm, this is exactly what I experience with it, and it is exactly what I experienced with the Denon I had used for years before.
So, I went to my friendly audio dealer, the same one who I purchased the 802Ds from and did some comparison tests...with the MA-6300, a McIntosh tube amp, and two Mac 600 watt monoblocs.
My conclusion? I am honestly not sure just how anyone can make the argument that all amps sound the same. Period. The differences weren't even subtle, they were obvious. I then went ahead and listened to even more amps and then concluded that no two of them sounded even remotely the same.
While I understand people who claim that all amps sound the same...theoretically they should I suppose, what I don't understand is how they can actually still make that claim even after listening to several different amps using the same speakers. And no, it's not subtle things like changing head position etc. The differences I have heard were so obvious it almost makes me wonder if the hearing in people who make the claim is just not very good.
Something of a proof to what I am saying is the fact that I had defined what I didn't like about my original Denon, and still experience in my McIntosh (the shrill high notes) and THEN AFTER having defined it, saw others with the same complaint. Well, if what I was experiencing was something in my own imagination, then how is it that others also have the same complaint having listened to the same equipment? When I listened to the 600wpc McIntosh monoblocs, I did not in any way shape or form experience the same shrill highs. As a matter of fact, of all the amps that I did audition, the only three that exhibited this behavior were the Denon, the MA-6300 and the Rotel that I listened to...and the McIntosh 6300, while still exhibiting this sound, still sounded far better than the Rotel.
So again, I just don't get it. While I believe that everyone here is saying what they truly believe and have experienced, so to ME it's like night an day with some of the comparisons. Is it just possible that people have different hearing capabilities and to some there is a difference and to others there isn't?