Vintage DACs And A Raspberry Pi

DAC

Before the days of iPod docks in every conceivable piece of audio equipment, most devices were actually built very well. Most shelf top equipment usually came with well designed circuits using quality components, and late 90s CD players were no exception. [Mariosis] heard of some very nice DACs found in some of these units and decided to take one out for a spin. He’s using a Raspberry Pi to play audio with the DAC found in a late 90s Kenwood CD player.

After fortune favored a CD player with a dead drive on [Mariosis]‘ workbench, he dug up the service manual and found some interesting chips – a PCM56 DAC, a little bit of logic, and an SM5807 oversampling chip that does all the conversion for the DAC.

This oversampling chip uses an I2S – not I2C – bus to carry the data from the CD to the DAC. There is, of course, an I2S driver for the Raspi, but the first attempts at playing audio didn’t result in anything. It turned out there was a problem with what the oversampler expected – the ‘standard’ I2S signal delays the data one tick behind the LRCLK signal.

There are two ways to fix this problem: programming a kernel driver, or building some custom logic to fix the problem. Obviously breaking out some flip-flops and NOR gates was the cooler option, giving [Mariosis] a great sounding stereo with a vintage DAC.

Fubarino-Contest: 1980’s CD Player with MPD

fubarino-cd-shelf-player

[Ronald] had to scramble to get his submission in, but we’re glad he did. His demo video shows the display of a 1980’s CD player working with Music Player Daemon. It’s really just the original display itself that works, but the project is not yet finished. However, is far enough along to show our URL when a track reaches the 22:00 mark.

The display is driven by an ATmega32 chip which uses a USB connection to receive commands from the computer running MPD. [Ronald] had troubles figuring out how to send int values over USB so he hacked his own protocol that just uses the LSB of each byte coming over the bus. After the break you can see the video, and read the description which he included with his submission. There is also a code package available here.


This is an entry in the Fubarino Contest for a chance at one of the 20 Fubarino SD boards which Microchip has put up as prizes!

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Fail of the Week: [Caleb's] Phosphorescent CD Player

fotw-caleb-hackfail

When [Caleb Kraft] was in full production for Hackaday he pumped a pile of awesome videos. But not every project worked out. He’s been a fan of the Fail of the Week posts, and sent in his own recollection of a project gone wrong. Above you can see his phosphorescent CD player. He prototyped the project in May of last year but technical issues and looming deadlines meant it never saw the light of day. We’ll fill you in on his fail after the jump.

Editor’s note: We need more tips about your own failure! There are a handful of submissions left in our reserves, but to keep this topic as a weekly column we need help tracking down more failed projects. Please document your past failures and send us a link to the write-up. If you don’t have a blog to post it on you may do what [Caleb] has done and email us directly. Remember to include any images and links to video which you may have.

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CD phonograph brings old-time charm to modern music

phonograph

[Jozerworx] had always wanted to build a CD player that looked like an old-time Victrola Phonograph player, though he never seemed to be able to find the time to do it. With all of his other projects out of the way, he decided to finally get started on building his phonograph.

He went garage sale hunting and found the perfect base for his project – an old wooden box adorned with tarnished brass hardware. He started in on the project immediately, dismantling a cheap CD player and mounting the motor/laser assembly on the top of the box. The CD player internals were installed inside the wooden box, along with a small audio amplifier stripped from a portable iPod speaker.

A brass horn was fashioned out of an ornament, in order to complete the phonograph feel, but also to act as a passive amplifier. He then mounted a series of switches on the top of the box to allow him to control the CD player’s basic functions.

[Jozerworx] says that it sounds decent, though there are some things he would change. He plans on switching out the audio amplifier and possibly the speakers at some point in the future. He is also still keeping his eye out for a larger, and more effective horn.

Steampunk CD player

This custom CD-player enclosure may not be your style, but you can’t deny that the fabrication techniques are top-notch (translated). This starts with a portable CD player and a set of amplified speakers. A brass plate serves as the base for the electronics, with the CD player internals mounted from the underside. The brass dome that covers the spinning disk also started as a sheet of metal, with quite a bit of work (translated) going into shaping and smoothing to achieve these results. The base and speaker boxes exhibit some fine woodworking, and there’s even additional electronics for lights, control buttons, and to drive the two analog meters. A lot of thought went into each component of this build and that’s how you put together a masterpiece.

[Thanks Polossatik]

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