I have seen an interview with B. Putzeys in which he stated that it's not important what is in the amplifier, but rather what isn't there in terms of distortion. His conclusion is that classic solid-state amplifiers have some type of distortion that tube amps don't have, which is why they are still very popular.
As seen in the pages here many have ditched their tubes for some of the newer GaN Class D amplifiers by AGD, Atmospheres and others.
Also he claims that separate components inhibiting progress and the sound chain.
if the amplifier is truly great that’s absolutely right. Sonic signatures are what you get when you approach the same ideal from different angles. There are a few distortion mechanisms conspicuously missing in Class D, mostly those related to the input stage of a Class A(B) solid-state amplifier and nonlinear capacitances. Those are also missing in valve [tube] amplifiers so it’s quite common for people to notice that a Class D amplifier is somehow reminiscent of valve amplification in terms of “sweetness” for want of a better word.
I’ve heard several reports of valve aficionados ditching their glassware and switching to Ncore. All I can conclude from that is that those people clearly weren’t actively seeking the distortion of valves as many believe, but instead had a legitimate beef with certain sonic aspects common to most solid-state designs. That’s one thing I have to explain again and again to my fellow doubters: when audiophiles report a particular listening experience, that experience is real. Trust that. Just don’t trust the explanation they proffer.
Also he claims that separate components inhibiting progress and the sound chain.
Our industry’s fixation on separate components is holding us up. The ultimate goal is sound, acoustical output. If you split the signal chain into separates and you require those to be exchangeable, you’re adding technical requirements to the interfaces between those boxes, just to standardize them. Case in point, why are we making amps with super high damping factors? Because a separate power amp means a passive crossover filter and if you don’t define the source impedance you get unpredictable results. But if you take the system level view and ask, “what problem are we trying to solve,” you can improve the distortion performance of a speaker driver enormously by tailoring the output impedance of the amp that’s driving it. That option isn’t available in a separates world. A system level approach allows you to get clearly better performance at a lower price, or something that is completely unattainable using classical means if you spend a bit more.
We suffer from what I call “loss of perspective.” Compared to amplifiers, speakers distort tremendously. But if you keep the speaker and the room the same you can still do an electronics shootout and clearly hear a difference. So you may be tempted to think: Oh, I really need a new preamp. We fool ourselves into thinking that our sonic horizon is expanded immeasurably because we can just change the preamp for a better one. It isn’t. Separates allow us to tinker at the boundaries of that horizon but only after shrinking it to something the size of our backyard.
Anyhow, that’s why I decided to leave amplifiers for now and do speakers instead. The first aim of Kii is to reduce the impact of the room acoustics. The correct list of items in the playback chain in the order of importance is: Room acoustics, speaker acoustics, drive units, then a long void followed by electronics as a remote third. The Kii design tries to make the speaker and the room switch position by reducing the amount of sound that excites room modes without first going to the listener. To do that at bass frequencies is quite a novelty and that’s where rooms need most help. You can’t build a passive speaker that does that so it’s only natural to make it active. The other benefits of combining electronics and speaker in one product follow naturally.
