Recording as many needed parts on the same analog magnetic recording track without generation loss

At your risk. See also a previous post. This is how Mike Oldfield created his Tubullar Bells demo by covering the erase head. Anyway at Pleiades lab the erase head of a Tascam Porta 03 cassette recorder has been disconected. Many singing parts were recorded on top of each other using just an SM58 at 24in above head connected to a Pleiades 175mH high pass filter. It is like painting on the same paper with different crayons. The 2nd pass partially blurs (only the very high frequencies are more affected) the 1st. The 3rd pass partrially blurs the 2nd and 1st. But the 4th, 5th,..., pass does not affect the 1st! For example a male singing voice immitated singing ducks of different age. Then the casstte recording of about 10 ducks in choir concert was played to Vicky's hi-fi system and she thought the recording had been done in a commercial good quality recording studio.