With 4 channels to select from you can get subtle tonal differences. Looking at the frequency plot below we can see each channel has the distinctive Head gap coloration of the low end, producing a ripple, this is a common characteristic in tape machines, looking at each channel from lowest plot (channel 1) to top plot (channel 4), we can see the two outer channels have a rise up to around 19kHz but the two center tracks are rolled off from around 14kHz. Of course this is subtle, However stacking instances will reveal a large coloration, As this is a 4 track machine bouncing tracks may have been common, resulting in a far more colored sound. Multiple stacked instances is something worth experimenting with. On the whole this will dramatically change the bass character and soften the upper mids.