We recently posted a video of the day showing Ewan Dobson playing a song on the guitar that is truly unbelievable. While his use of this effect is unique, the trick behind it has a long history, particularly in country music. The great country guitarist Albert Lee is the artist probably most often associated with this trick.
Here's a cool interview with Albert where he talks about it:
This trick has been used by many guitarists to produce some very memorable solos. Check out Elton John's guitarist John Jorgensen's solo with the Helecasters on The Orange Bolssom Special:
The trick to this technique is using a very specific delay setting with a specific tempo.
First set the delay so it produces only 1 repeat. On many pedals this might mean dialing the feedback to 0%. Next set it so that the volume of the 1 repeat is equal to the plucked note. This might be setting "delay" to 100%. Now we need to do just a little math to set the rate. Divide the tempo of the song by 45 and that equals the rate in seconds. As an example, if your tempo is 120, divide 45 by 120 and your rate is 0.375 seconds or 375 milliseconds. This is of course easiest with a delay unit that allows you to set your rate in milliseconds, but once you have the sound in your head you can use a pedal without this and learn to estimate. This is one technique where a metronome or drum machine is critical. If your tempo starts to drift at all, the delayed notes won't line up, and you'll have a mess!