phonograph

16 Articles

Retrotechtacular: Stereo Records

March 28, 2017 by 41 Comments

The 20th century saw some amazing technological developments. We went from airplanes to the moon. We went from slide rules to digital computers. Crank telephones to cell phones. But two of the most amazing feats of that era were ones that non-technical people probably hardly think about. The transformation of radio and TV from mono and black and white, to stereo and color. What was interesting about both of these is that engineers managed to find a way to push the new better result into the same form as the old version and — this is the amazing part — do it in such a way that the old technology still worked. Maybe it is the rate that new technology moves today, but we aren’t doing that today. Digital TV required all-new everything: transmitters, receivers, frequencies, and recording gear. Good luck trying to play the latest video game on your 25-year-old PC.

It is hard to remember when stores were full of all sorts of audio and video media. We’ve noticed that all forms of media are starting to vanish. Everything audio and video are all streamed or downloaded these days. Records, 8-tracks, cassettes, and even CDs and DVDs are vanishing. However, vinyl records have made a come back in the last few years for their novelty or nostalgic value.

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Laser Cut Your Own Vinyl Records

August 7, 2015 by 45 Comments

[Amanda Ghassaei] has created an awesome hack for making your own vinyl records using a laser cutter from an MP3 file. Her excellent hack uses a Processing sketch that converts a digital audio file into a vector graphics file, which is then burned onto vinyl using a laser cutter. We saw a demo of this at the FabLab11 conference, and it’s an impressive hack.

One of the best parts of her write up are the details of how she arrived at the appropriate processing settings to get the record sounding as good as possible, but still be cuttable. It’s an object lesson in how you iterate on a project, trying different approaches and settings until you find the one that works. She also decided to take it a few steps further, cutting records on paper and wood for the ultimate eco-friendly record collection.

Audiophiles should avoid this technique though. Due to limitations in the resolution of the laser cutter, [Amanda] ended up having to reduce the bandwidth of the audio signal to 4.5Khz and use a 5-bit sampling depth. That translates to a rather tinny-sounding record. Vinyl record snobs can breathe easy: this isn’t going to replace their beloved white-hot stampers. For the rest of us, there are always records etched into tortillas.

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Phonographs Through The Eye Of An Electron Microscope

June 16, 2015 by 32 Comments

Hackaday Prize judge [Ben Krasnow] has been busy lately. He’s put his scanning electron microscope (SEM) to work creating an animation of a phonograph needle playing a record. (YouTube link) This is the same 80’s SEM [Ben] hacked back in November. Unfortunately, [Ben’s]  JSM-T200 isn’t quite large enough to hold an entire 12″ LP, so he had to cut a small section of a record out. The vinyl mods weren’t done there though. SEMs need a conductive surface for imagingphono_anim_1. Vinyl is an insulator. [Ben] dealt with this by using his vacuum chamber to evaporate a thin layer of silver on the vinyl.

Just imaging the record wouldn’t be enough; [Ben] wanted an animation of a needle traveling through the record grove. He tore apart an old phonograph needle and installed it in on a copper wire in the SEM. Thanks to the dual stage setup of the JSM-T200, [Ben] was able to move the record-chip and needle independently. He could then move the record underneath the needle as if it were actually playing. [Ben] used his oscilloscope to record 60 frames, each spaced 50 microns apart. He used octave to process the data, and wound up with the awesome GIF animation you see on the left. 

pits[Ben] wasn’t done though. He checked out a few other recording formats, including CD and DVD optical media, and capacitance electronic disc, an obscure format from RCA which failed miserably in the market. The toughest challenge [Ben] faced was imaging the CD media. The familiar pits of a CD are stored on a thin aluminum layer sandwiched between the lacquer label and the plastic disc. He tried dissolving the plastic with chemicals, but enough plastic was left behind to distort the image. The solution turned out to be double-sided tape. Sticking some tape down on the CD and peeling it off cleanly removed the aluminum, and provided a sturdy substrate with which to mount the sample in the SEM.

We’re curious if stereo audio data can be extracted from the SEM images.  [Oona] managed to do this with a mono recording from a toy robot.  Who’s going to be the first one to break out the image analysis software and capture some audio from [Ben’s] images?

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Putting New Into The Old – A Phonograph Upgrade.

March 17, 2015 by 28 Comments

[smellsofbikes] recently came into possession of a 1970’s “stereo radio phonograph” cabinet consisting of a vinyl record player, AM and FM radio, and eight track tape player. The radio worked, the turntable didn’t sound too nice, and the tape player didn’t work at all. A new needle fixed the turntable, but the eight-track was in bad shape. So he replaced the tape player with a BeagleBoneBlack which plays streaming internet radio.

Hopefully, this fix is temporary, since he has carefully disconnected the tape player connections in the hope of fixing it soon. The swap out involved a fair bit of engineering, so he’s split his build log into several bite sized chunks. The first step was to set up the BBB, upgrade it and add in all the network and audio related stuff. Audio on the BBB is available only via the HDMI port, but [smellsofbikes] had a USB soundcard handy, so the next step was setting that up. He installed mpg321 – the command line mp3 player and set it up to play music streaming from somafm. Next up was getting some scripts and programs to run automatically during system bootup. The final part of the setup was adding a WiFi router as a repeater connected to the BBB via an ethernet cable. He could have used a tiny WiFi USB dongle, but he already had the router lying around, and he wanted to dedicate USB to audio functions alone, and use the Ethernet port for Internet.

He then worked on identifying the wires that go from the tape player to the amplifier, spliced them, and hooked them up to the audio sound card on the BBB. With this done, the upgrade was more or less complete – the system played streaming music and stations could be switched remotely (via SSH to BBB). [smellsofbikes] reckoned it would be nice to use the existing controls in the phonograph cabinet to control the internet streaming music, instead of controlling it via a remote computer. The cabinet had 4 indicator lamps that indicated which track was being played and a button to switch between tracks. He removed the old indicator panel and put in a fresh PCB, designed in KiCad and cut on his LPKF circuit board plotter. An aluminum knob machined out of hex bar-stock works as the new track change button. At this point, he called it a wrap. The BBB and Asus router go inside the cabinet, and the old (non-functional) tape player is put in place. Quite an interesting build, and we look forward to when he actually gets the tape player working. [Alan Martin], aka “The Most Interesting Engineer In The World” has told him that “it is a moral imperative that you repair the eight-track and get it working”. [Alan] has promised to send [smellsofbikes] a suitcase full of brand new, still in their plastic wrappers, eight-track tapes when he gets it working.

Atomic Powered Robots And Records Played With Optics

March 3, 2014 by 28 Comments

mike

If you were a child of the 80’s or early 90’s you probably remember Magic Mike. He went by many names, but he always said the same thing “I am the atomic powered robot. Please give my best wishes to everybody!” [Oona’s] version of Mike had been malfunctioning for a few years. He’d stopped talking! She decided he needed more input, so she disassembled Mike to reveal the flesh colored plastic box in the center of his chest. This talkbox was used as a sound module in several toys. Before the days of cheap digital playback devices, sounds were recorded in a decidedly analog fashion. [Oona] found that Mike’s voice and sound effects were recorded on a tiny phonograph record in his chest. The phonograph was spun up by an electric motor, but the playback and amplification system was all mechanical, consisting of a needle coupled to a small plastic loudspeaker. The system was very similar to the early phonograph designs.

Mike’s record contained two interwoven spiral tracks. Interwoven tracks is a technique that has been used before, albeit rarely on commercial albums. One track contained Mike’s voice, the other the sound of his laser gun. The track to be played would be chosen at random depending upon where the needle and record stopped after the previous play. The record completely sidetracked [Oona’s] repair work. She decided to try to read the record optically. She started with a high resolution image (image link) of the record, and wrote some Perl code to interpolate a spiral around the grooves. The result was rather noisy, and contained quite a bit of crosstalk. [Oona] tried again with laser illumination using a Lego train set. Unfortunately the Lego train / laser system wasn’t smooth enough to get a good image. In the end she used a bit of Gimp magic and was able to pull better audio from her original image. We never did find out if she put poor Mike back together though.

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A Retro, Not Steampunk, Media Center

October 2, 2013 by 26 Comments

[toddfx] wanted to put his Raspberry Pi to work and set about creating one of the best stereos we’ve ever seen: It’s called the Audio Infuser 4700, and turns a conglomeration of old disused stereo equipment into a functional piece of art.

[toddfx] used a Raspberry Pi to stream music over WiFi, but also wanted to play some classic vinyl. He took apart an old Yamaha YP-D4 turntable. stripped it to the bone, and created a fantastic oak enclosure around it. To this, he added a seven-band graphic EQ, aux jacks (both in and out), and a tiny 5″ CRT from an old portable TV.

Where this build really gets great is the fabrication. The front panels have all their graphics and lettering engraved via a toner-transfer like method using copper sulphate and salt. [todd] got the idea from this thread and we have to say the results are unbelievable.

Even though this awesome device only used for music, [toddfx] used the tiny color CRT to its fullest. Flick one switch, and it’s an oscilloscope-like display. Flick another switch, and it’s the output of the Raspberry Pi loaded up with a few MAME games including Pacman, Asteroids, and Space Invaders.

[toddfx] put up a build page for his Audio Infuser and an awesome video for his project, available below.

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Fisher-Price Record Player Plays Stairway To Heaven

May 24, 2012 by 27 Comments

[Fred Murphy] has an old Fisher-Price music box/record player that has lost many of its disks over the last 40 years. It’s a very simple device – concentric grooves in a plastic disk have plastic bumps that are picked up by the tines of the record player ‘cartridge.’ Seeing as how this toy is basically a music box, [Fred] figured making his own records would be well within his grasp; he did the reasonable thing and made a Stairway to Heaven disk for a toy music box.

To figure out where to place the ‘bumps’ for the musical tines, [Fred] built a small tool in Visual C# 2010 that allowed him to place notes on a scale and generate the requisite GCode for the disk. After sending this file to his CNC mill, [Fred] had an acrylic disk that played Led Zeppelin on a child’s music box.

Of course, this Instructable wouldn’t be complete without a video demo of Stairway blasting out of this record player. You can check that out after the break.

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