Tape Loop Echo Made With an Actual Tape Loop

A lot of digital processes are named after an old analog device that they’ve since replaced. It’s not uncommon to “tape” a show nowadays, for example, even though the recording work is actually done by a digital video recorder. Sometimes, though, the old analog devices have a certain je ne sais quoi that is desirable even in today’s digital world. This is certainly the case with [Dima]’s tape loop echo which is actually made with a physical tape loop.

The process of building the tape loop hardware is surprisingly non-technical. By positioning a recording head and a playback head right next to one another, a delay is introduced. An echo is created by mixing the original live sound signal with this delayed signal coming from the tape By varying the speed of the tape or altering several other variables, many different-sounding effects can be achieved.

Although in practice it’s not as simple as it sounds (the device required a lot of trial-and-error), the resulting effect is one that Pink Floyd or Beck would surely be proud of. Analog isn’t the only way to go though, there are plenty of digital effects that are easily created, and some with interesting mounting options as well.

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Busted Wah Pedal Becomes New Synth Tool

Sometimes we get lucky and find a part we need for a project in our parts drawer. [Scissorfeind] got even luckier and found a part for his project lying around in the street. It was a Crybaby Wah pedal, a classic effects pedal typically used for a guitar. Since it was somewhat damaged, [Scissorfeind] got to work creating a control voltage (CV) and volume circuit for his Korg synthesizer.

For those who aren’t synthesizer aficionados, CV is a method of controlling the pitch of a tone. A higher voltage creates a higher tone and vice-versa. The wah pedal has a rocker on it that allows one’s foot to control the effect, but this particular one has been modified for CV instead of the wah-wah sound these pedals normally make. [Scissorfeind] built in a switch that will allow it to control volume as well, which makes this pedal quite unique in the effects world.

[Scissorfeind] built the custom circuit out of other parts he had lying around (presumably not in the street) and put the entire thing together on perfboard, then fit it all back together in the pedal. Now he has a great control voltage pedal for the vintage Korg synthesizer he recently restored! [Scissorfeind] knows his way around a synth, but if you’re looking to get started on a synthesizer project we have a great tutorial for you!

Guitar foot controller uses DSP for audio effects


This a screenshot taken from [Pierre’s] demonstration of an electric guitar effects pedal combined with DSP and Pure Data. He pulls this off by connecting the guitar directly to the computer, then feeds the computer’s audio output to the guitar amp.

The foot controls include a pedal and eight buttons, all monitored by an Arduino. Pure Data, a visual programming language, interprets the input coming from the Arduino over USB and alters the incoming audio using digital signal processing. [Pierre] manages the audio connection using the JACK Audio Connection Kit software package.

In the video after the break he’s using a laptop for most of the work, but he has also managed to pull this off with a Raspberry Pi. There’s no audio input on the RPi board, but he’s been using a USB sound card anyway. The other USB port connects the Arduino and he’s in business.

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Fabbing a guitar tremolo stompbox

There’s a lot of builders around whose first foray in electron manipulation was building effects pedals for guitars. It looks like [Dino] might be getting back to his roots with his tremolo effects box how-to.

Last week, [Dino] found an old 5-watt tube amp in someone’s trash and decided to bring it back to a functional state. With his new trem effect, it looks like [Dino] might be getting the band back together.

Apart from tiny boost circuits, a tremolo is generally the simplest effect pedal you can make. All you’ll need to do is vary the amplitude of the guitar’s signal at regular intervals. After that, it’s only a matter of pretending you’re playing through a rotating Leslie speaker.

To get his trem working, [Dino] set up a 555 circuit to flash a LED at regular intervals. This LED is encased in heat-shrink tubing along with a photocell. This setup controls an LM386 amplifier. The build is really simple, but from the video after the break we can tell it sounds great.

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Feel like we do with a bass guitar talk box


Hacker [Dino Segovis] wrote in to share the latest hack from his HackAWeek series, and this time around he has constructed a talk box for his bass guitar. Providing you are old enough, you probably remember when the talk box made its way into mainstream music, on the “Frampton Comes Alive” album.

The concept of a talk box is pretty simple. A small speaker is built into a sealed enclosure, which carries the sound from the musician’s guitar to his mouth via a plastic tube. The tube is placed in the musician’s mouth, near the microphone. When his mouth is moved, the sound from the guitar is modified and reflected into the microphone.

[Dino] built a similar system using his bass guitar and an amplifier hacked together from an old tape deck. He initially ran into problems with the sound not making it all the way up the tube due to the bass’ low frequency. He had an ‘Aha!’ moment and mounted the speaker on the mic rather than down on the floor, which seems to have fixed the issue.

Be sure to check out the video below to see his talk box in action.

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