Thank you all for advise, guys!
That's really a good point! I'm having enough problems to get parts for my Atari system. On the other side I would like to have a second ability to record and mix the sounds with digital tracks controlled by a sequencer. I've heard that you could use one tape track with a recorded SMPTE line for controlling a sequencer. For this option the tape recorder should come with 4 tracks minimum, I'm guessing.
Regards, Danny