Adding Analog Tape Echo Effects with a Cassette Player

What is tape delay?

In music, there is a wide variety of effects that can be applied to sound such as pitch shifting, distortions, noise, and reverb. The last entry is special in that it can introduce more "body" to the sound and simulate a shared, physical space across several environments. Nowadays, reverb is typically added at the post-production mixing stage or with modifier pedals that musicians step on for brief periods of time to change what their instruments do.

The 1950s brought with it not only new electric instruments, but also ways to store and play back recorded audio from magnetic tape. Shortly after its introduction, it was discovered that recording the current audio from an instrument and then subsequently playing it back on that very same tape would lead to an echo effect. By adjusting the speed of the tape and mixing in other sources of noise, a very complex and rich-sounding reverb could be created.

As a throwback to this simpler time, YouTuber and maker Mark Gutierrez sought to build his own fully analog tape delay system from just a walkman and a few potentiometers in hopes of recreating its classic sound profile.

Disassembling a cassette player

Tape delays require a source of moving magnetic tape, and because tape cassette players are far more difficult to find, he went with a relatively inexpensive Sony Walkman clone. Once stripped of its housing, the microphone was replaced by a 1/4" barrel plug jack for connecting a patch cable while the speaker leads were reconnected to a mixing board. The cassette player already had a head for continuous recording, so all Gutierrez had to do was add a secondary playback head to read the just-written audio data. Finally, a larger potentiometer replaced the playback speed trim-pot so it could be accessed externally and tune the delay between playing a note and hearing its echo.

The enclosure

With Gutierrez now able to record and replay sounds from the walkman, his next few steps revolved around arranging each component so that it fit nicely on a display. The top row has both the playback speed potentiometer and a mixer for finely adjusting inputs and outputs on the adjacent patchboard. Just below the mixer is the cassette player assembly which is only the cassette, the loading mechanism, and the motorized backplane. The two heads for recording and playback were mounted to the side so that the moving tape could be a focal point.

How does it sound?

Towards the end of his excellent build log video, Gutierrez swapped out his traditional reverb pedal for the tape delay and connected a guitar. The resulting song is filled with a mix of clear guitar chords and a steady stream of distortions, echos, and a little bit of hiss that all contribute towards a very unique sound profile.