Why do I like Class AB better than Class A?

So I just purchased a Plinius SA 100 MKIII, and have had 2 listening sessions comparing both with the toggle switch. To me clearly the AB is more detailed and focused, the A is warm but a little fuzzy and bloated, although I would give it a slight nod on just vocal songs. Am I just not use to the sound as this is my first A amp or have I not let it properly warm up for class A (1hour or so).
Don't get me wrong, i love the amp, great bottom end slam but I don't hear the holy grail from Class A. Thanks in advance for the input guys.
Hi BBag,

To each his own...good to know you've got options! Meanwhile, i am a big fan of Class A...and wonder...what is your source? While your ears are the ultimate judge for you, just since you ask, i will play devil's advocate just for fun. Is the A/B hardening up what might be a less precise source or pre? While A is displaying exactly what you've got upstream? AGain...just playing devil's advocate.

In any event, with Plinius, no doubt you've got great sound no matter what. Enjoy!!!
Does this amplifier have enough hours on it to be considered broken in?
Hey guys, my source is MacMini running PureMusic, Wyred4Souns DAC 2, Aiff. I think I have solved the issue, I hadn't let her warm up enough, I thought 20 or so minutes was going to be sufficient but it was not, I give her 2 hours+ and is much much better. Though it still prefer AB with busy or complicated music like progressive metal and such. Thanks again
Class AB has more power,that is why you like it better.
I've owned the SA100 MkIII and the difference between Class A and Class AB isn't that huge though appreciable. Similarly I find the sound to be smoother, warmer, more organic and liquid with Class A. Music sounds leaner, sharper and more crisp in Class AB apart from having a slight edge in speed and transient attack - ideal for rock and music with lots of dynamic swings. With rock and metal, Class AB will be more ideal as music tends to sound slower and thicker in Class A due to the added warmth in the midrange.

Apart from the minute sound differences, Class A operation is also very inefficient. When I had the Plinius I usually listen in Class AB and find it to work well enough across a wide genre of music.
Ryder, great description of the Plinius, it is exactly how I feel it sounds between A and AB. If I may ask what did you move onto for amplification and why? Thanks in advance.
Barfbag, I moved on to the Naim as the speakers I had were mostly warm and smooth sounding designs, hence the match between the speakers and Plinius is too much of a good thing. Music lacks excitement and boogie factor and sounds lethargic in dynamic passages. Something just didn't sound right.

Having said that, I am sure the Plinius is an excellent amp that will sound great with speakers that are leaner, more neutral, open or forward. It's all about system synergy.

I will agree with Ryder on that one. I have frequently heard a Plinius SA250 MKIV and although the SA100 is not in the same league, there is a definite Plinius housesound.

But in my sense, and my preferences, choice of gear is highly dependable of type of music preferences. Soft jazz, feminine voices and small orchestra music will come out beautifully on class A amps because of their general richness in tonality. Music that produce fast transients and dynamic contrast will generally be better on faster amps and in this sense, class A and probably tube amps will fall second to an AB of good quality.
True class A in my opinion benefits heavily from true balanced circuitry as well. Single ended is fine, but most amps will perform better all out XLR, even A-B.

Class A is a little weaker in wattage 9 times out of 10 and with an extra 6 db of gain from a balanced connection it does perform much better.

Plinius has a balanced connection so if you can do it go full balanced and really hear benefits regardless if its A or A-B.
Actually, the Plinius is only fully balanced when it's bridged as a monoblock.