Originally introduced in 1975, Dan Armstrong Sound Modifiers are a range of simple, compact, and rugged accessories which may be used with any electrified instrument. They can be heard on many of the most influential and enduring recordings of the ‘70s and original vintage examples can still be found in the arsenal of many top session musicians.

These units are carefully hand-built to authentic 1975 Dan Armstrong specifications in the United States by Grafton Electronics to ensure the highest quality and original vintage sound.

These unique effects were designed to plug directly into the output of a guitar or bass guitar to give the player fingertip control of the sound, but they work just as well plugged into an electric keyboard or the output of any electronic accessory. The effects can easily be modified for use at the amp instead of the guitar. Dan Armstrong Effects are "True Bypass".