All-in-one integrated, 10-15K range, class A/B only

You should audition Luxman 509 or 590axii.
I was also looking initially for all in one and hence bought Naim Nova. I was running (still run sometimes for a change) my aerial acoustics 7T with Naim Nova. I love them and still have it, probably will keep it. I recently bought Luxman 590axii, as I wanted more musical class A tube like sound. They are end game amplifiers. They have not even broken and am already in love with it. They are different level all together. They are more than sufficient to power any speaker with decent sensitivity. Their rated 30 watts is very conservative. I am using Nova as streamer/DAC to Luxman 590axii. Eventually I might change Nova to reference quality streamer/Dac. I am now researching which streamer/DAC to buy. The idea of all in one is always intriguing but I am settling for streamer/DAC and integrated amp combo. Again, keep Luxman 509 (if you want more dynamic sound) and 590axii (more musical) in your list. 

Trying to decide between the 509x vs the 590axii. What does more dynamic sound means vs more musical? I guess more musical means it's more smooth and flows nicely?

I am no expert, but dynamics is more to do with clear delineation across various dynamic spectrum of sound (soft to all the way up to loud notes). Little bit more analytical and may be more definition of every spectrum. Yes, musical is very smooth, without much emphasis of clear distinction of various notes. Just melowy and emphasis on high and mids. 

Thanks. I suppose why audiophiles swear by class A is because of the smoothness. I read they do not prefer A/B because of the "noise" that they hear (or could it be caused by the "definition" and clarity?). In theory, no recording is perfect and so maybe with the higher definition, they are hearing the noise from the recording and not really the noise from the amp?

I've heard the 509x (A/B) and it sounds nice. Have not had a chance to hear the 590axii (A) yet.

I totally agree with Riaa. A lot of people listen to this guy Jay (WC) who is quite entertaining, but he changes a gear more often that I change my sucks. He does not burn it long enough and always mix and match. I had all 3 integrated in my house at the same time. Luxman 509x, Luxman 590axII  (both well burned) and new (about 25 hours on it after my initial burn) Accuhase E-800. To my ears the luxman 509x is good but nothing special still has that typical class A/B sound that is at the higher volumes becomes harsher. The luxman 590axII is a real gem for the price. Tonal colors, micro details, sweet highs and bass are very good. I liked it much better than 509x. After burning new accuphase E-800 for 25 hours, I could not wait anymore and decided to give it a try. All I can say this is a sound I was after all these years. Meat with details. Tonal colors are outstanding, dynamics, texture all are on a different level from luxman integrates. But most amazing for me is the bass this integrated produces. I never heard that deep tight textured bass form my Sonus Faber Amati Tradition. And they say that accuphase needs long time to burn. So I expect it to be even better within couple months. Is that the best integrated on a market. Of cause not. Its all matter of what we like and what and how we listen.  Bottom line one has to listen with his own ears and read other opinions as information only. We all have different preferences and taste. Now wait, this post will get removed, because I praised accuphase over luxman.