Pink Floyd

Today’s delays are the grandchildren of the Echo-Plex and other tape units that put extra shimmer in recordings by Jimi Hendrix and David Gilmour in the 1960s. But they fail less, are easier to control with precision and preserve sound quality far better.
Delays are different than reverbs. Delays actually repeat the notes you play, which decay with repetition, until they fade. You can set the time between repetitions in milliseconds. The amount of repetitions can also be adjusted as can the level of the mix between your original guitar signal and the repeats generated by the delay. Some delays are also samplers that allow you to create loops, but at the very least a basic delay box needs to have delay time, repeat (a/k/a feedback) and mix level settings.
Some argue that a delay’s time should be set to the tempo of a tune. That’s how the Edge gets his classic sound on “Pride (In the Name of Love).” But unless you’re covering delay-soaked hits like that song or Pink Floyd’s “Run Like Hell” there are no hard and fast rules about how any effect should be used — ever. Always remember this. It will make your recordings and performances less predictable, and that’s a good thing.

However, if you’re looking to emulate the rhythmic delay approach of songs like those, you need to tweak the delay pedal so the repeat notes are in the same tempo as the song. In the Edge’s case, he’s playing eighth notes with a 50/50 or so blend of effect and guitar level, with three or four repetitions for each note. Some delays have presets for this “dotted eighth note” approach, due to its popularity. The “tap tempo” feature on a number of different delay pedals can help you arrive there on the fly, but don’t try to zip into using such highly specific delay effects without practicing extensively first.
Of course, besides repeating notes delay is a wonderful way to make your guitar’s tone bulge like a hippo’s belly. Try setting a delay to 350 milliseconds and the same three or four repeats per note discussed above. Then set the mix level at about 25-to-35-percent effect. You will sound like a giant. Instantly. Guaranteed.
Other effects can also be accomplished easily with a delay pedal, like slapback, which requires one repeated note with a short decay to produce the sound’s signature retro vibe. Using multiple delay pedals can also take you to interesting places. That’s a technique that has been used by Joe Satriani and Steve Vai to fatten up and elongate their tones. Blend delays with others effects, too, to generate cool and even classic tones. Just because Hendrix used a phase shifter and a tape delay to get the great warbling guitar sound on “House Burning Down” doesn’t mean you can’t do the same thing with a modern digital unit, and with more precision. And if you’re looking for the kind of signal degradation that came with a tape delay back in the day, modern analog delay pedals provide a close match while offering more precision and durability than tape units, at a lower cost.