But there remains that question, and I'm dope enough to ask it...if there is truly no difference based on power amp topology alone, why do people report hearing differences, even with the power amps our sound running friends like to use?
Again, certainly not slamming micro technology. I think I've bought enough micros to prove that I like the format
For a fews of reasons:
1) As Jerrold and others (including me) have said, this WAS true back in the day, and it is hard to 'not listen with your eyes' once something has become 'common knowledge' over years.
2) SO many times, this is based on someone listening to 2 or 3 amps and then attributing the difference between those amps to the wrong thing. So someone plays a DB750 and then a Markbass F500, and concluded 'well, the big amp has a lot more bottom' so class D amps must all sound 'quick and punchy but without the big slam'. They don't take into account wattage differences, designers tone goals, hi passing, preamp voicing and a million other things. Kind of similar to back in the day when players would play a Ric and then a P Bass and conclude 'neck throughs have more sustain and bolt-ons have more punch'
3) Front of house guys.... I have never heard a front of house guy believe there is a differece in the slam or whatever of a current SMPS amp and the old iron... not once. Most of them are so excited about their new rack of Crowns or whatever that you can't shut them up about them! That being said, just like a great player who doesn't really take time to understand gear, there are many front of house engineers (very good ones) who really don't know much about the actual workings of the gear.
4) Talking to older repair techs... 'yeah, this new stuff sucks'. Same in all categories. You typically stick with what you understand and replace a lack of experience and knowledge of recent improvements with disdain! I'm of the age where I unfortunately understand this.
IMO and a lot of IME. Again, if you blind listening test 20 amps, with different power amp topologies, I would be very comfortable predicting that NO ONE could identify the amp topology beyond random chance... period.
In your case, where you love your SVT, you are completely correct saying that no other amp really sounds and feels like it. However, that is true of other tube amps, or big iron solid state amps, or micro's. All amps sound different for hundreds or reasons. Nothing sounded like my heavy Glockenklang either... until Glockenklang made a class D version with a very high quality class D/SMPS module and identical preamp!