Why would anyone want class AB amp when class A always sounds better ?

You don't always get what you want

but if you spend your dime

you just might find

you get what you need

Seems to me that whichever one is designed the best will sound better, be it A, A/B, or D - those letters do not specify qualitylll 

Class A sound better?  No, lots of factors to consider.  You have first of all assumed Class A sounds better.  Not always true.

Class A sound better? No, lots of factors to consider. You have first of all assumed Class A sounds better. Not always true.

Exactly.  I own four Class A amps so obviously like what they offer (aside from the heat and the electric bill), but horses for courses - some Class AB amps sound better in some systems. Generalizations like the original posts are meant to stir fuss, not logical response.

I use a Class AB tube amp in my main system as a matter of fact, and I prefer it with those speakers to the 100 lb. + Class A monos I used to use. OTOH I use a stereo Class A amp with some electrostatics and it is a great match.  YMMV