Bruce C Roe (bcr@ih4ess.ih.lucent.com) wrote on 15 Jul 1996 on
the sd-mailing list:
Regarding connecting the (presumedly stereo) two outputs of a mini-disk
(or any other audio line source) together: These two signals will not
be identical when used in mono applications, and forcing them together
with a short may introduce additional distortion with the respective
amplifiers fighting each other. Using just one would be better. If
you need to mix the 2 signals a simple resistive divider can do the
job. Use a resistor of higher impedance than the source and lower
than the load. For line applications (high impedance) I recommend
a 2,200 ohm resistor connected to each of the outputs. This puts
4,400 ohms between the two amp outputs. Connect the other end of the 2 resistors
together, and to the load. This gives a 1,100 ohm impedance to the
load. Bruce Roe