New portable amplifier

[croccodillo]

Hello all,

As you maybe already know, I'm bulding a new headphone portable amplifier.

Yesterday night the courier bring to my door the free samples I asked for to Analog Devices, two pieces of AD8397ARDZ (the version with enhanced thermal capability) op-amp!

I asked for the free samples about a week ago, and actually didn't believe they would really ship them to me... I'm really surprised and happy.

Few LT1115, LT1677 and LT1010 should be on the road to my house too.
We'll see if they will arrive.

In the meanwhile, I ordered two differents LiPo charging, protection and step-up boards, THIS and THIS.
With these boards I can charge a LiPo battery, protect it and I should have a 5V output to power the amplifier. GREAT!
We'll see when the boards will arrive.
I already have preparred a LiPo battery, a Nokia one to which I removed the protection circuit (alredy included in the above board).

Next step will be to order asuitable enclosure and an Alps potentiometer.

So, I'm ready to start!

So, my idea now is to use one of the two AD8397 as a virtual ground (both channels paralleled), and the other one as output buffer for the two audio channels.
All the circuit will be powered at 5V, from the above step-up board.

I still have to understand how to disconnect the battery from stepup of the board when not in use: I'd like to leave the protection/charging circuit always connected to the battery, in manner I can charge it with the amplifier powered down, but I'd also like to disconnect the battery fom the stepup to save its juice.
Probably I'll have to cut few trace on the board to do it.

Currently I do not know if to use the AD8397 as a normal op-amp, or to use it a s a buffer, and preceding it with another op-amp (LT1115?).

Any idea?
Any schematic you can throw to me?

Ciao,
Giovanni