@saurabhgarg Class A amps have warmer sound, in general. However, keep in mind each brand will have its own house sound. In example, Pass Labs amps are on the warmer side of neutral. Their Class A/B amps like the X250.8 are biased into Class A for the first 20-25w then transitions into Class A/B with tons of headroom. Pass Class A amps are even warmer. While they’re primarily biased into Class A, they still have some headroom in Class A/B. But the sound is unmistakably Pass Labs - warm, laid back with big bass. To me, Pass X series sound more dynamic and open than their XA series but what works for you in your system is impossible to predict.
Luxman Class A/B or Class A will also have their house sound and even the Class A Luxman will probably retain some of the top end qualities and may be only slightly warmer. It won’t be a full 180 from the sound you’re getting now.
If you can swing the Diablo 300, that would be my choice if I were you. With that amp you can experiment with pretty much any speaker down the road.
Good luck!