@ kiko

What’s your main issue about this recording setup? (except the use of the minijack socket and the internal soundcard…)

If I was you I would get a “minijack stereo-minijack stereo” cable plus an adaptor to make it 1/4" jack


So you go from A4’s Headphone socket to MacBookPro minijack input (I’m presuming it is a stereo input).
Just check if you can modify properly the input gain in order to have a good out from the A4 and a not too hot signal fed at the input stage.

Another cabling option could be to use a Y-cable: “2x TS jack > minijack stereo”


this time you go from the A4’s Main L/R Out.

All of the time I would go for the 2nd option!
P.S.
buy anyway an ext. soundcard…A4 deserves it!

I hope I got a bit of what you were asking about…