Let me end the Premp/Amplifier sound debate ...

It seems to me, that the bottom line here is that all people hear differently. Some people have very acute hearing; other people don't. Those people who have very acute hearing maybe will hear a differences between various amplifiers or preamplifiers and those who don't have such acute hearing will not.  Those who don't hear a difference will think that there are no differences, while those who have better hearing your differences. The real issue is how you feel about the sound of your equipment. If you can't hear a difference there's no reason to spend more. I know I for one get jazzed up about some component based on reviews that call it the best thing since sliced bread and I am compelled to want to buy that piece of equipment. When I put it in my system I find that it might have a better sound in some respects but no means is it "a night and day oh my God I have a new system type" difference like the reviewed portrayed.  I think that the real interesting point made by the OP in this case is the diminishing marginal utility of equipment. Is there a $10,000 difference between a $10,000 preamp and a $20,000 one, or is it just audible. If it's just "audible" then, one must decide whether that "audible" difference is worth another $10K.  That is a personal choice and there is really no right or wrong.

Eric, great post and worthy of discussion.

By the way Todd, very nice setup. I’m sure you enjoy many listening sessions. By the way I had the Yamaha ZX-9 many years ago and gave it to my son. It’s a fine-sounding receiver.

On Amir and ASR, I respect what he is trying to do. Amir’s opinions are worth listening to and he has some very good points, but many ASR forum members are just annoying. Speaking from my personal experience, I believe the measurements we use as standard do not tell the whole story. Not at all.

In my humble opinion, I cannot understand how any audiophiles obsessively build their sound systems over the years and still believe that all amplifiers, when level matched, essentially sound the same. I find that contention wildly wrong. Without going deep into how different topologies sound different (to me, they most assuredly do), each amplifiers model is capable in different ways, with strengths and weaknesses. Some are extremely fast and ‘airy’ , whereas others are more rich, and seductive. Some throw massive enveloping soundstages and present as a complete sound-picture you look on from the outside, while others focus more on immediacy and ‘I am here-ness’. Some are more laid back with a slightly recessed perspective, while others are very forward.

My believe is, that as technology advances, the higher-end products are becoming more similar in sound, being better able to approach the ‘absolute sound’.

For example, a Devialet Expert Pro sounds different than a Parasound Halo, or a NuForce, or Audio Research Classic 150 mono-blocks, or a bridged pair of Mark Levinson 27.5 and so on and so forth.

Pre-amps and Cables; same thing.

Nice videos. I think I hear what I associate with tubes right at the start of one of those videos with the cymbal crash. I'm generally happier with the solid state sound but it'd be nice to be able to switch over to tubes with the flick of a switch if I felt in the mood.

If you doubt there are sonic differences between amplifiers, both preamps and power amps, A/B a few. If you cannot hear any differences you are probably not going to be affected by these choices. But to me, Amp and Preamp selection, next to speaker selection, make the the biggest difference in sound of any system I have ever heard. So no need to chase amps if you hear little or no differences. Geez, I wish it was that easy.

I don't remember what Julian Hirsch said about amplifiers but AudioScienceReview does not say that all amplifiers sound the same or that they measure the same.