Making A Tape Echo The Traditional Way

[Juan Nicola] has taken inspiration from the musician hackers of old and re-purposed a reel-to-reel tape recorder into a tape-echo for his guitar with a built-in valve amplifier (video in Spanish).

The principle is to record the sound of the guitar onto a piece of moving magnetic tape, then to read it back again a short time later.  This signal is mixed with the live input and re-recorded back onto the tape further back.  The effect is heard as an echo, and this approach was very popular before digital effects became readily available.

[Juan] installed a new read-head onto his Grundig TK40 and managed to find a suitable mechanical arrangement to keep it all in place.  He has since updated the project by moving to a tape loop, allowing an infinite play-time by re-using the same piece of tape over and over.

Turning tape machines into echo effects is not a new idea, and we’ve shown a few of them over the years, but every one is slightly different!

Both versions are shown after the break.  YouTube closed-caption auto-translate might come in handy here for non-Spanish speakers.

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Simple Universal Modem Helps Save And Load Data From Tape

Back in the early days of the home computer revolution, data was commonly saved on tape. Even better, those tapes would make an almighty racket if you played them on a stereo, because the data was stored in an audio format.  The Simple Universal Modem from [Anders Nielsen] is built to work in a similar way, turning data into audio and vice versa.

The project consists of a circuit for modulating data into audio, and demodulating audio back into data. It’s “universal” because [Anders] has designed it to be as format-agnostic as possible. It doesn’t matter whether you want to store data on a digital voice recorder, a cassette deck, or an old reel-to-reel. This build should work fairly well on all of them!

On the modulation side of things, it’s designed to be as analog-friendly as possible. Rather than just spitting out rough square waves, it modulates them into nice smooth sine waves with fewer harmonics. On the demodulation side, it’s got an LM393 comparator which can read data on tape and spit out a clean square wave for easy decoding by digital circuitry.

If you find yourself trying to recover old data off tapes, or writing to them for a retrocomputing project, this build might be just what you need. [Anders] even goes as far as demonstrating its use with an old reel-to-reel deck in a helpful YouTube video.

There really were some weird ways of storing data way back when. Just ask IBM. Video after the break.

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Automate Parts Kitting With This Innovative SMD Tape Slicer

Nobody likes a tedious manual job prone to repetitive stress injury, and such tasks rightly inspire an automated solution. This automatic SMD tape cutter is a good example of automating such a chore, while leaving plenty of room for further development.

We’re used to seeing such tactical automation projects from [Mr Innovative], each of which centers on an oddly specific task. In this case, the task involves cutting a strip containing a specific number of SMD resistors from a reel, perhaps for assembling kits of parts. The mechanism is simple: a stepper motor with a rubber friction wheel to drive the tape, and a nasty-looking guillotine to cut the tape. The cutter is particularly interesting, using as it does a short length of linear bearing to carry a holder for a razor blade that’s mounted perpendicular to the SMD tape. The holder is mounted to a small motor via a crank, and when the proper number of parts have been fed out, the motor rotates one revolution, driving the angled blade quickly down and then back up. This results in a shearing cut rather than the clipping action seen in this automated wire cutter, also by [Mr Innovative].

Curiously, there seems to be no feedback mechanism to actually measure how many resistors have been dispensed. We assume [Mr Innovative] is just counting steps, but it seems easy enough to integrate a photosensor to count the number of drive sprocket holes in the tape. It also seems like a few simple changes would allow this machine to accommodate SMD tapes of different sizes, making it generally useful for SMD kitting. It’s still pretty cool as a tactical project, though, and does a great job inspiring future improvements.

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Pitch Sequencer Turns Tascam Tape Deck Into Instrument

The cool thing about magnetic tape is that by varying the speed at which you play it back, you can vary the pitch of the output. [Issac] decided to take advantage of this, executing a fancy digitally-controlled pitch mod on his Tascam Porta 02 tape deck.

The build uses a Raspberry Pi Pico, which employs PWM to control the speed of the tape drive’s motor. This is achieved with the use of an NPN transistor driven by the PWM output of the Pico. This allows accurate control of motor speed, and thus pitch.

With that sorted out, the project was fleshed out with an OLED screen and a rotary encoder. These allow various patches or scripts to be run on the Pico, controlling the motor speed of the tape player in various ways. With a bit of work, [Issac] was also able to create a function that converted MIDI note values into PWM values that determine various motor speeds.

The natural thing to do next was to put in a tape with a looping sample at a set pitch, and then vary it in a sequence controlled by the Pico. The 8 steps of the sequence can be manually set with the rotary control, and in future, [Issac] even plans to add a real MIDI input, allowing the system to act as a monophonic synth.

If you prefer other routes to pitch shifting shenanigans, check out this project. Video after the break.

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DEC microVAX with tape drive

Bake It To ReMake It: Cooking Old Magnetic Tape To Recover Data

Those of us old enough may remember the heyday of the text adventure game genre from the first time around. London-based Magnetic Scrolls was an early pioneering company producing titles for the first Amiga and Atari ST platforms. Fast-forward to 2017 and [Hugh Steers], the original co-founder and core developer for Magnetic Scrolls has formed an initiative to revive and re-release the original games on modern platforms. Since the 1980s-era DEC MicroVAX used originally for development is not particularly rare in retro computing circles, and media containing source code was found in someone’s loft space, reviving the games was not a tall order.

First, he needed to recover a copy of the original source code from the backup tapes. But there was a problem, it turns out that the decaying tapes used a unstable polyurethane-based binder to stick the oxide material (which is what stores the data) to the backing tape, and this binder can absorb water over the years.

Not much happens until you try to read the tape, then you trip over the so-called sticky-shed syndrome. Secondly you may find that a small amount of the oxide layer sheds from the tape, coating the read head, rollers and guides inside the complicated tape mechanism. This quickly results in it gumming up, and jamming, potentially chewing up the tape and destroying it permanently.

This was further exacerbated by the behaviour of the DEC TK50Z tape drive, which needed to shuttle the whole length of the tape as part of its normal operation.

A temporary solution was to bake the tape in an oven to drive out the moisture and reduce the stickiness enough to run it through the drive safely. Then only the oxide-shedding problem remained. The TK50Z drive was swapped for a TZ30 which shuttles the tape less, but also critically with a simple hack, would allow the heads to be cleaned with IPA between read passes. This was enough to keep the gumming up at bay and allow enough data to be read from the tapes to recover several games worth of code, ready for the re-releasing process.

The video after the break shows [Rob Jarratt] working through the process of the data recovery.

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Modern Tape Echo Made Easy

Modern popular music increasingly relies on more and more complicated and intricate equipment and algorithms to generate catchy tunes, but even decades ago this was still the case. The only difference between then and now was that most of the equipment in the past was analog instead of digital. For example, the humble tape echo was originally made by running a loop of magnetic tape over a recording head and then immediately playing it back. Old analog machines from that era are getting harder and harder to find, so [Adam Paul] decided to make his own.

At first, [Adam] planned to use standard cassette tapes in various configurations in order to achieve the desired effect, but this proved to be too cumbersome and he eventually switched his design to using the cassette internals in a custom tape deck. The final design includes a small loop of tape inside of the enclosure with a motor driving a spindle. The tape is passed over a record head, then a read head, and then an erase head in order to achieve the echo sound. All of this is done from inside of the device itself, with 1/4″ jacks provided so that the musician can plug in their instrument of choice just like a standard effects pedal would be configured.

The entire build is designed to be buildable and repairable using readily-available parts as well, which solves the problem of maintaining (or even finding) parts from dedicated tape echo machines from decades ago. We like the sound from the analog device, as well as the fact that it’s still an analog device in a world of otherwise digital substitutes. Much like this magnetic tape-based synthesizer we featured about a year ago.

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Audio Cassette Tape Data Retrospective

It has been a long time since we stored software and computer data on audiotape. But it used to be the de facto standard for hobby computers and [Noel] has a great video about the Amstrad’s system (embedded below) which was pretty typical and how the process could be sped up since today, you have perfect audio reproduction, especially compared to consumer-grade audiotape.

The cassette tapes suffered from several problems. The tape had an inherently low bandwidth, there was quite a bit of noise present from the analog circuitry and heads, and the transport speed wasn’t necessarily constant. However, you can easily digitally synthesize relatively noise-free sound at high fidelity and rock-solid frequency. So basically a microcontroller, like an Arduino, can look like an extremely high-quality tape drive.

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