Primaudio wrote:
That's almost right. Quarter track records on half of each track of a
half-track. Corresponds to tracks 1 and 3 of a 4 track head as the tape moves
in the forward direction. Cassette is the same except twice as dinky.

Just FTR, cassette has left and right on the same side, so a mono (1/2 track)
cassette head plays back a stereo cassette correctly in mono (L+R); in contrast
to the OP's apparent problem.

L1 --
R1 --
R2 --
L2 --