Pitch Sequencer Turns Tascam Tape Deck Into Instrument

May 11, 2022 by Lewin Day 4 Comments

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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Know Audio: Mixtapes, Tape Loops, And Razor Blades

December 20, 2021 by Jenny List 16 Comments

In our no-nonsense journey through the world of audio technology we’ve so far have looked at digital audio and the vinyl disk recording. What’s missing? Magnetic tape, the once-ubiquitous recording medium that first revolutionised the broadcast and recording industries in the mid-20th-century, and went on to be a mainstay of home audio before spawning the entire field of personal audio. Unless you’re an enthusiast or collector, it’s likely you won’t have a tape deck in your audio setup here in 2021 and you’ll probably be loading your 8-bit games from SD card rather than cassette, but surprisingly there are still plenty of audio cassettes released as novelties or ephemeral collectables.

The Device That Made The Sound Of The Latter Half Of The 20th Century

"Like a travelling razor blade", a Blattnerphone steel-strip tape recorder at the BBC in 1937. Douglas Hallam, Jr., Public domain. — “Like a travelling razor blade”, a Blattnerphone steel-strip tape recorder at the BBC in 1937. Douglas Hallam, Jr., Public domain.

The first magnetic recordings were made directly on metal wires, but metal fatigues as it bends. By coating a flexible plastic tape in ferrous particles, the same simple technique of laying down an audio signal as variations in the magnetic field could be made smaller, lighter, and more robust. But the key to the format’s runaway success is the technical advancements that differentiate those 1950s machines from their wire recorder ancestors.

Whether it is a humble cassette recorder or a top-end studio multitrack, all tape recorders are very similar. There are two reels that hold the tape: the playback reel that houses the recording, and the take-up reel that stores the tape as it plays in the machine. The take-up reel is lightly driven to run faster than the tape speed, and the playback reel has a slight braking force to keep the tape under tension at all times. Continue reading “Know Audio: Mixtapes, Tape Loops, And Razor Blades” →

Bringing A Century Stereo Into The 21st Century

June 9, 2015 by Bryan Cockfield 14 Comments

Way back in the previous century, people used to use magnetized strips of tape to play music. It might be hard to believe in today’s digital world, but these “cassette” tapes were once all the rage. [Steve] aka [pinter75] recently found a Bang & Olufsen stereo with this exact type of antequated audio playback device, and decided to upgrade it with something a little more modern.

Once the unit arrived from eBay and got an electronic tune-up, [pinter75] grabbed a Galaxy S3 out of his parts drawer and got to work installing it in the old cassette deck location. He used a laser cutter to make a faceplate for the phone so it could be easily installed (and removed if he decides to put the tape deck back in the future).

The next step was wiring up power and soldering the audio output directly to the AUX pins on the stereo. Once everything was buttoned up [pinter75] found that everything worked perfectly, and mounted the stereo prominently on his wall. It’s always great when equipment like this is upgraded and repaired rather than thrown out.

Bluetooth Boombox For That 80s Nostalgia

November 20, 2014 by Bryan Cockfield 23 Comments

Sure, anyone can go buy a bluetooth speaker for their portable music needs. But for something a little more unique, at least in this decade, [Daniel] aka [speedfox] went with an 80s-style boombox and outfitted it with a bluetooth module.

The retro boombox was delivered with a few scratches and a broken radio, but the tape decks were still in decent shape so it was ready to be hacked. [speedfox] tied the Bluetooth audio output to the tape reader on one of the boombox’s tape decks, but this revealed a problem: the bass was overwhelming the rest of the sound. [speedfox] fixed this by adding a filter which worked until the power was tied in to the Bluetooth module and produced a lot of RF noise in the audio output. THIS problem was finally resolved with an audio transformer on both sides of the stereo signal. Finally!

After putting all of the new electronics in the case (and safely out of the way of the 120V AC input!) [speedfox] now has a classy stereo that’s ready to rock some Run-D.M.C. or Heavy D. He notes that the audio filter could use a little tweaking, and he’d also like to restore the functionality of the original buttons on the boombox, but it’s a great start with more functionality than he’d get from something off-the-shelf!

LEGO Robot Lays Dominoes Not Eggs

January 11, 2010 by Mike Szczys 17 Comments

[Mattias] brings the awesome once more with his LEGO robot that sets up dominoes. You’ll remember his work from the wooden keyboard case and the mechanical binary adder. This time around he’s still exercising those woodworking skills by making his own domino tiles, but it’s the robot that makes this interesting. In the must-see video after the break the device lays perfectly straight, perfectly spaced dominoes just begging to be upset by a spoiled toddler. The robot is nothing more than handful of LEGO parts powered by a tape deck motor. The parts may be meager, but there’s an abundance of ingenuity tied up in the design.

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