Know Audio: Get Into The Groove

November 18, 2021 by Jenny List 62 Comments

The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Dydric [CC BY-SA 2.5)], via Wikimedia Commons. — The legendary Technics SL1200 direct-drive turntable, as used by countless DJs. Photo by Dydric CC-BY-SA 2.5

For me, the vinyl record player is the spiritual home of my audio listening experience, probably because I’m of the last generation to grow up when vinyl was king. The 12″ album, with its full-size sleeve and copious sleeve notes, used to be an integral part of musical enjoyment that hasn’t been adequately replicated in the age of streaming.

And like anyone who became an adult while CD players were still expensive luxury items, I started my journey into Hi-Fi with a turntable set-up that sounded pretty good. Since a new generation have in recent years rediscovered vinyl, it’s once again something that should be part of any review of audio technology.

I would have started this piece with a full run-down of the constituent parts of a good turntable, but since that’s a piece that I wrote back in 2017, it’s time to investigate some of the audiophile claims about vinyl recordings. It’s fair to say that this is an area where a lot of complete rubbish is spouted by people who should know better, and that’s something I find immensely entertaining to poke fun at. Buckle up. Continue reading “Know Audio: Get Into The Groove” →

Better 3D Scans Through A Slowed Down Turntable

August 31, 2021 by Tom Nardi 6 Comments

3D scanners aren’t cheap, and the last thing you want to see after purchasing one is bad data. But that’s what [Dave Does] and others were getting from their Revopoint POP scanners until some communal brainstorming uncovered the reason: the motorized turntable that came with the Kickstarter edition of the product was spinning too fast for the software to accurately keep track of the object. So he decided to replace the stepper motor controller in his turntable and document the process for anyone else who’s scanner might be struggling.

In the video below, [Dave] pops open the plastic case of the turntable and reveals a pretty sparse interior. There’s an incredible amount of empty space inside, and even some mounting studs to screw down new components, should you want to get into some hardcore upgrades. But for his purposes, a generic stepper motor controller that featured a potentiometer to adjust the speed was enough. He found a suitable board online for around $5 USD, and got to designing a 3D printed bracket that mates up to the existing screw holes on the turntable.

But it’s not exactly a drop-in replacement. For one thing, you’ve got to pop a hole in the side of the enclosure for the potentiometer knob to stick out of. You’ve also got to solder wires coming from the original DC jack and power switch to the new board to get it hooked up, but at least the motor plugs right in. In the video below, you can see [Dave] demonstrate the impressively deep throttle capability of the new driver.

If you’d rather build than buy, we’ve covered some impressive DIY turntables in the past that could fit the bill nicely, from automatic models that handle camera control to fully 3D printed versions that you’ve got to crank yourself.

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Anything Becomes A Clock

August 15, 2020 by Bryan Cockfield 5 Comments

Clocks are a popular project around here, and with good reason. There’s a ton of options, and there’s always a new take on ways to tell time. Clocks using lasers, words, or even ball bearings are all atypical ways of displaying time, but like a mathematician looking for a general proof of a long-understood idea this clock from [Julldozer] shows us a way to turn any object into a clock.

His build uses AA-powered clock movements that you would find on any typical wall clock, rather than reaching for his go-to solution of an Arduino and a stepper motor. The motors that drive the hands in these movements are extremely low-torque and low-power which is what allows them to last for so long with such a small power source. He uses two of them, one for hours and one for minutes, to which he attaches a custom-built lazy Suzan. The turntable needs to be extremely low-friction so as to avoid a situation where he has to change batteries every day, so after some 3D printing he has two rotating plates which can hold any object in order to tell him the current time.

While he didn’t design a clock from scratch or reinvent any other wheels, the part of this project that shines is the way he was able to utilize such a low-power motor to turn something so much heavier. This could have uses well outside the realm of timekeeping, and reminds us of this 3D-printed gear set from last year’s Hackaday prize.

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Hackaday Podcast 066: The Audio Overdub Episode; Tape Loop Scratcher, Typewriter Simulator, And Relay Adder

May 8, 2020 by Mike Szczys 3 Comments

Hackaday editors Elliot Williams and Mike Szczys stomp through a forest full of highly evolved hardware hacks. This week seems particularly plump with audio-related projects, like the thwack-tackular soldenoid typewriter simulator. But it’s the tape-loop scratcher that steals our hearts; an instrument that’s kind of two-turntables-and-a-microphone meets melloman. We hear the clicks of 10-bit numbers falling into place in a delightful adder, and follow it up with the beeps and sweeps of a smartphone-based metal detector.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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DJ Scratches Out Club Music With Tape, Not Turntables

April 30, 2020 by Dan Maloney 20 Comments

It goes without saying that not everyone has the same taste in music, and what sounds amazing to one person will be the next person’s noise. But even if you’re not into hip-hop and the whole DJ scene, it’s hard not to be impressed with what [Jeremy Bell] has done here with his homemade tape loop “scratching” rig.

Most people have probably seen a DJ in a club using dual turntables to scratch or “scrub” a vinyl record back and forth to create effects that add to the music. Part musician and part performance artist, DJs and “turntablists” tend to be real crowd-pleasers. [Jeremy]’s “ScrubBoard” uses a loop of 2″ audiotape, the kind recording studios once used for multitrack recordings. The loop is driven across a wide platen by a motor with a foot pedal control, which he can use to quickly reverse the direction of travel and control the speed of the tape. A pair of playback heads are wired into the amplifier and can be positioned anywhere on the sometimes moving, sometimes stationary tape. The sounds he can create are rhythmic, percussive, and at times frenetic, but they’re always interesting. Check it out in action in the video below.

This version of the ScrubBoard is far from the first [Jeremy] has built. You may recall his first prototype from our coverage in 2014; that one used just a few feet of 1/4″ tape fixed to a board. He was still able to get some great sounds from it, but this version should really change things for him.

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Guitar Effect Built From An Old Record Player

December 9, 2019 by Tom Nardi 4 Comments

With little more than a gutted record player, a light bulb, and the legendary 555 timer IC, [Jacob Ellzey] has constructed this very slick optical tremolo effect for his guitar. By modulating the volume of the input signal, the device creates the wavering effect demonstrated in the video after the break.

The key is a vinyl record with large tabs cut out of it. As the record spins, these voids alternately block and unblock a small incandescent bulb. A common GL5537 photoresistor, mounted on the arm that originally held the player’s needle, picks up the varying light levels and passes that on to the electronics underneath the deck. An important note here is that different spacing and sizing of the cutouts will change the sound produced by the effect. [Jacob] has already produced a few different designs and plans on experimenting with more now that the electronics are completed.

Under the hood there’s a voltage divider and low gain amplifier connected to the photoresistor, and also a 555 timer circuit that’s driving the incandescent bulb. Once he was done fiddling with them, the circuit was moved to a neat little protoboard. A pair of potentiometers mounted through the side of the record player allow for adjusting the depth of the effect itself, as well as the output volume. Naturally, there’s also an external foot pedal that allows keying the effect on and off without taking your hands from the guitar.

As is usually the case, everything was going well on this project until the final moments, when [Jacob] found that the circuit and bulb were both browning out when powered from the same transformer. As a quick fix, he gutted a Keurig and used its transformer to drive the light bulb by itself. With independent power supplies, he was ready to rock.

Of course this isn’t the first time we’ve seen a piece of consumer electronics modified into a guitar effect, but if you’re looking for something a bit more built for purpose, there’s plenty of high-tech options to keep you busy.

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Turntable Spins Color And Sound Together

October 27, 2019 by Erin Pinheiro 5 Comments

If you can’t grow your own synesthesia, buying electronics to do it for you is fine. Such is the case with the CHROMATIC by [Xavier Gazon], an artist who turns all kinds of electronics into circuit-bent musical art pieces. His project turns an old Philips Music 5120 turntable into a colorful MIDI sequencer, inspired by older 20th century instruments such as the Optophonic Piano and the Luminaphone.

The CHROMATIC uses colored pucks placed on a converted turntable to perform a looping sequence of chords in a given musical scale, generating MIDI data as output. Where its inspirations used primitive optics as their medium, this project employs a Teensy microcontroller and two modern optical sensors to do the work. One of these is a simple infrared sensor which tracks a white spot on the edge of the turntable, generating a MIDI clock signal to keep everything quantized and in sync. The other is a color sensor mounted on the tone arm, which can tell what color it sees and the height of the arm from the turntable.

While the instrument is still in beta testing phase details on how notes are generated aren’t yet given, though the general idea is that they are dictated by the color the tone arm sees and its position above the platter. Moving the tone arm changes which pucks it tracks, and the speed of the turntable can also be adjusted, changing how the melody sounds.

The CHROMATIC is a very interesting project, but it’s not the first optical-based turntable hack we’ve seen here. We’ve also seen a much weirder use for a color sensor, too. Check out the video of this one in action after the break.

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