Okay, I was confused and had to look it up:
You're right SPDIF is a 2 channel protocol, but it can be RCA or optical.
ADAT and SPDIF (which is Sony) can use the same cables (TOSLINK (which is Toshiba)).
I thought SPDIF was the cable. I meant ADAT with TOSLINK cables.
There's another thing I just understood.
I didn't think about the fact, that many producers are using a mixing console.
I don't and I don't think I want to, because it needs a lot of space.
Okay I've got an old Yamaha 8/2 from the early 90s and a Soundcraft 12/4 which is 15 – 20 years old.
So I think I will need an interface with Mic inputs and phantom power.
Or maybe, if I want to record drums, it is better to look for a mixing console with 16 in- and outputs and then use a interface like the Ferrofish???