Geez, my wife (and she isn’t “into it”) can hear the differences between amps... trust me, I’ve had a few now.
To the OP, I agree with what you were told by the sales guy. Current can make a significant difference, possibly very profound. A class D amp is going to sound very different from a class A amp, even A/B, different circuits. Just is what it is. Then you get into SET, FET, MOSFET, bipolar circuits within all of that. They all have sonic signatures. I also agree that a tube preamp into an SS amp can make huge differences. “Better” is in the ears of the beholder... I just put a Rogue Audio RP5 into my system with a Pass Labs XA25, so far the combo is great. The Rogue replace an XP12 SS pre. The tubes just sound a bit smoother, more “natural” to my ears. No listening fatigue at all. Anyway, this game is about experimenting and finding the best combo you can afford... it’s a lot of fun. Sometimes.
To the OP, I agree with what you were told by the sales guy. Current can make a significant difference, possibly very profound. A class D amp is going to sound very different from a class A amp, even A/B, different circuits. Just is what it is. Then you get into SET, FET, MOSFET, bipolar circuits within all of that. They all have sonic signatures. I also agree that a tube preamp into an SS amp can make huge differences. “Better” is in the ears of the beholder... I just put a Rogue Audio RP5 into my system with a Pass Labs XA25, so far the combo is great. The Rogue replace an XP12 SS pre. The tubes just sound a bit smoother, more “natural” to my ears. No listening fatigue at all. Anyway, this game is about experimenting and finding the best combo you can afford... it’s a lot of fun. Sometimes.