The DOD FX-90 analog delay pedal has undergone multiple revisions, with the most prevalent version being rev.A. The Setback pedal is based on rev.A but incorporates changes to the analog through and clock set-up. The FET bypass switching used in the FX-90 has been removed in the Setback, which now features true bypass. The Setback also includes value changes for better performance and uses more common values than the original design. The schematic for the Setback includes these changes.

Additionally, the Setback pedal offers a Tails option. This allows the delay repeats to continue even when the pedal is turned off, providing a spill-over effect. The entire unit is true bypass, but the Tails feature allows for the delay repeats to be heard even when the input is disconnected. However, the Tails option is not necessary for the build and is mentioned in the notes.

Overall, the Setback pedal is an improved version of the DOD FX-90, with changes made for better performance and more common values. It also offers a Tails option for those who prefer the delay repeats to spill over when the pedal is turned off.

Summary created by AI from the original source.