DIY Cassette Tape Guitar Delay

Digital delay pedals are pretty good nowadays and even the cheaper ones do a pretty good job at emulating the sound of old analog delay effects. And that’s good, because the original delay effects can run you a pretty penny. If you’re in to DIY electronics, though, analog delay effects can still be built without breaking the bank, and, as an example, [Matsound] has made a tape delay using an old tape deck and regular cassette tapes.

The core of the build is a portable 3-head cassette recorder, in this case a Marantz PMD430. The circuit has been around for a while – it was originally found in an issue of Stompboxology in the 90’s. The basic idea is that with a three-head recorder (erase, record, play) the distance between the record and play heads creates a delay and you increase this delay by slowing down the recorder’s motor. You combine the output from the recorder with the dry signal from your input and, viola, tape delay.

[Matsound] added a cool feature where you can control the speed of the motor with a control voltage, so if you connect it to a keyboard and produce different voltages from different keys, you get weird, spacey effects. The video gives an overview of the features and some details of the build process are in the video’s description.

A nice build built into a nice case and a great effect! Maybe you wouldn’t take it out gigging with you, but it sure sounds pretty good!  Other delay pedals have been mentioned on the site before, like this digital delay pedal and here’s another take on the cassette tape delay.

19 thoughts on “DIY Cassette Tape Guitar Delay

  1. If only Fripp had known about this! Slowing the motor to increase the delay approaches 0 as a limit in terms of fidelity. What you need to do is increase the distance between the heads. The simplest method for this is to make the tape go elsewhere between the two heads.

  2. I’ve never found a three head cassette deck in the garbage.

    I thought in analog days they brought the tape out to increase the delay, but it’s a long time since I paid attention. But those were reel to reel, the motors were AC and not easy to change speed. Many cassette decks use DC motors, making it way easier. Though the record/playback heads are likely in one package rather than separate.

    If you bring the tape out to loop around something before returning to the cassette, not only can you get more delay, but you could add a tape head for those lacking a separate record head. One could even make do with the usual.head from another cassette deck.

    Though oddly I have enough to.make a sort of studio, things found in the garbage. A drm machine, two large efects boxes (they do multiple effects), a midi keyboard, a mixer. Not great, but free. I did once see some exotic digital recording device, but decided after looking at the boards that it was too old to be useful

      1. A vcr has potential. But more complicated so maybe not as simple to use the needed parts.

        Elemntary Electronics decades ago showed a delay line using a garden hose, an earphone or speaker at one end, a microphone at the other end. Primitive, but maybe better than reverb springs which could easily be banged and introduce noise.

        1. There are some techniques with spring reverbs that make them less boingy and with more “sheen” – like driving two identical spring reverb units, and combining their outputs out of phase. Also they like to be driven by a current source.

    1. I’ve fixed a few tape echo machines. Those I’ve worked on used an adjustable head (usually playback) and timing was adjusted by moving the head back and forth. These used custom tape cartridges/loops so you could have 6-8″ of tape stretched out for this purpose.
      The Echochord used this method *and* offered a slow-speed drive mode so you had twice the adjustment range.

  3. Quite a few years ago I did in my block alley, turned out to be solder joints in the motor control board. Good deck. The problem with cassette format is that there is little room for a extra head or heads. Yet alone room to move it unless you redo the entire tape path.

    I have a 3 head RTR tape deck and a slide rail from a flatbed scanner, would be nice to have the time to hack up an Echoplex sliding head machine. With sliding playback head you create the variable speed effects, as well as basic time of delay. Ditch the AC motor and use a PM-DC motor in the old school RTR deck.

  4. Could get longer delays with higher fidelity due to higher tape speed by mounting a record head to go in the left cassette opening. Pop in an endless loop cassette and you can play with delay for hours without needing to rewind. Mount an erase head in the right cassette opening to wipe all trace of the previous recording.

    For a stronger signal you could use 4 track heads from an auto reverse deck and record two stereo tracks going the same direction.

    1. Only one problem with that concept, looping tapes have a splice point that doesn’t record sound, so you would always have a silent spot. And on most looping tapes that would be every 20-60s.

  5. if you can find a 3-head cassette deck for free or cheap, fine; but if you try to buy something, it would be easier to make a flexible and decent-sounding delay with an old reel-to-reel deck or two and 1/4″ tape.

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