Echoplex

The Maestro Echoplex EP-4 is a tape delay effect unit that emerged in the early 1960s and set the standard for these effects. The EP-4 is the final variant of the Echoplex and includes several design changes. It features independent Microphone and Instrument inputs, as well as two separate inputs for a footswitch labeled the Echo On/Off and Playback inputs. The Echo Delay Control is a sliding post on the top that adjusts the length of delay on the echo. The EP-4 also has an added output buffer to help improve impedance matching with other equipment.

The dimensions of the Maestro Echoplex EP-4 are as follows:
- Height: 8 inches (20.3 cm)
- Width: 14 1/2 inches (36.8 cm)
- Depth: 9 inches (22.9 cm)

The unit includes an LED "record input" meter on the face and is notable for dropping a sound-on-sound feature, which was considered outdated in an era of cheap tape recorders. The Echo Repeats and Echo Volume knobs work independently to control the intensity, and the tone of the return can be altered with the Treble and Bass knobs. The EP-4 is known for its flexibility and unique sound, making it a highly desirable effects processor.

The EP-4 model was introduced in the mid-1970s and is considered one of the coolest effects processors ever made, with a lot of flexibility and a sound all its own.