Actually in my case the reverse was true. In my earlier all solid state setup, I had many CDs that I found unlistenable. It was usually more contemporary music that had bad compression or badly mastered. I tried finding better quality pressings/remasters but not everything was available. But once I tried an Ayon CD2S tube CDP, they all became listenable again. And without an overly warm and syrupy sound too. Still with great dynamics and pace but somehow just more listenable.
A friend of mine recently swapped out his CJ GAT preamp and Jadis JA120 special edition for a Karan built preamp and stereo power amp (tweaked by ASI) but I didn't feel he lost out a lot in the swap. I suspect with his fundamentals in place (dedicated power lines, Sound Application SA-X conditioner and ASI power cords), the overall tonality and sound quality was very similar.
A friend of mine recently swapped out his CJ GAT preamp and Jadis JA120 special edition for a Karan built preamp and stereo power amp (tweaked by ASI) but I didn't feel he lost out a lot in the swap. I suspect with his fundamentals in place (dedicated power lines, Sound Application SA-X conditioner and ASI power cords), the overall tonality and sound quality was very similar.