Delay
Space category, section-level.
Repeats the signal after a short gap, over and over, fading as it goes.
Controls
Time. How far apart the repeats are. At its shortest the repeat arrives so soon it thickens the sound rather than echoing it, the slap-back sound. Longer settings separate into distinct rhythmic repeats.
Feedback. How many times the echo comes back. Turned down you get a repeat or two and then silence. Turned up the repeats trail on and start to fill the space. Raise it gradually: with a long time and high feedback the echoes pile up faster than the mix can absorb them.
Mix. How loud the repeats are next to the original. Kept low the track just feels bigger, without an obvious echo. Brought up, the repeats become part of the arrangement, which is where ambient and dub sounds live. On anything rhythmic, keep it moderate so the echoes do not blur the groove.
Time and mix interact. Short time with a loud mix doubles the sound, close to chorus. Long time with a quiet mix adds space. Long time with a loud mix builds a wash, which is atmospheric right up until it is muddy.
Presets
Slap, Echo, Long Echo, Tape.
When to use it
A little on leads adds depth. More on guitar builds ambient texture. Because it is section-level, the verse can stay dry and the bridge can open up.