Boss DD-8 Reference Manual page 16

Setting the Output Method
Direct Mute
This produces effect output with B input and A output.
B
A
DD-8
RETURN
Guitar Amplifier
* The direct sound is not output from A, regardless of whether
the effect is on or off.
* Be sure to lower the output level of any device being
connected.
16
SEND
INPUT
Guitar
Stereo
With A input and A/B output, this provides mono-in stereo-out
delay.
Guitar Amplifier
With A/B input and A/B output, this provides stereo-in stereo-out
delay.
Guitar Amplifier
* You can select any of three types of stereo delay modes.
For more information, refer to "Setting the Mode for Stereo
Delay" (p. 18).
B
A A
DD-8 Guitar
Keyboard
B B
A A
DD-8 Stereo Effect Unit
(chorus, flanger etc.)
Guitar