I did a comparison between the Audio Research DS450 and the GS150 at a local shop recently. GS Pre frontend and VPI turntable via Vandersteen speakers. Nice setup. The sound thru the DS450 ($9k), a switching amp wasn't too bad, but, wasn't what I'd call wonderful. Then the dealer switched over to the GS150 ($20k), yeah, MUCH better. In fact I brought my daughter along with me and she told the salesman flat out "the 1st amp was Broken..."
Now, one would expect a $20k amp to sound better than a $9k amp. And, tubes do sound different than SS. But, at $9k the switcher produced "sound" no magic, no music really. So, yeah switching amps have a long, long way to go. The GS150 tube amp, not really sure it could get much better, nor do I feel it would Need to. Hey, maybe in 50 years switching amps will be as good as modern tube amps are today :)
Now, one would expect a $20k amp to sound better than a $9k amp. And, tubes do sound different than SS. But, at $9k the switcher produced "sound" no magic, no music really. So, yeah switching amps have a long, long way to go. The GS150 tube amp, not really sure it could get much better, nor do I feel it would Need to. Hey, maybe in 50 years switching amps will be as good as modern tube amps are today :)