Do I really need a recorder, battery box and external mics to get a decent stereo recording?
In my opinion, definitely.
I thought the many 'all-in-one' units had gotten to the point where they were sufficient for decent concert recording (again 'decent' is subjective).
Our definition of all in ones differs from yours. You are thinking all in one box with using the mics.
We do use all in ones but, primarily for the pre-amp and a/d stage, not the mics. Depending on the model,
quite a few are more than sufficient for pulling sweet tapes.
I really just want something to sit in my pocket...you go to whole new level of complex when you start adding components!
If that's what you want, then go for it. Your
concert recordings will never consistently be listenable.
This is the truth. You will only get out, what you put in.
Just running internals
in your pocket is about as half-assed as it gets.
Not trying to be harsh with you specifically but, we get newcomers with this same exact idea/thread everyday it seems.
Instead of giving you a half-assed answer, I will just tell you the truth.
If this was just for band practice or the like, i would say go for it.
However your understanding of what it takes to have a passable effort is wrong.
Once again, I hope you don't take offense to me being honest. Your idea and expectations will end
with disappointment at the final product.
Honestly, do you really deep down think the majority of the tapes you would make with a pocket
recorder, uhm, in your pocket could be listenable?