Circuit Bent CD Player Is Glitch Heaven

Circuit bending is the art of creatively short circuiting low voltage hardware to create interesting and unexpected results. It’s generally applied to things like Furbys, old Casio keyboards, or early consoles to create audio and video glitches for artistic effect. It’s often practiced with a random approach, but by bringing in a little knowledge, you can get astounding results. [r20029] decided to apply her knowledge of CD players and RAM to create this glitched out Sony Discman.

Portable CD players face the difficult problem of vibration and shocks causing the laser to skip tracks on the disc, leading to annoying stutters in audio playback. To get around this, better models feature a RAM chip acting as a buffer that allows the player to read ahead. The audio is played from the RAM, giving the laser time to find its track again and refill the buffer when shocks occur. As long as the laser can get back on track fast enough before the buffer runs out, the listener won’t hear any audible disturbances.

[r20029] soldered wires to the leads of the RAM chip, and broke everything out into banana jacks to create a patch bay for experimenting. By shorting the various leads of the chip, this allows both data and addressing of the RAM to be manipulated. This can lead to audio samples being played back out of sync, samples being mashed up with addresses, and all manner of other weird combinations. This jumbled, disordered playback of damaged samples is what creates the glitchy sounds desired. [r20029] notes that certain connections on the patchbay will cause playback to freeze. Turning the anti-skip feature off and back on will allow playback to resume.

The write up highlights the basic methodology of the hack if you wish to replicate it – simply find the anti-skip RAM on your own CD player by looking for address lines, and break out the pins to a patch bay yourself. This should be possible on most modern CD players with antiskip functionality; it would be interesting to see it in action on a model that can also play back MP3 files from a data CD.

Circuit bending is a fun and safe way to get into electronics, and you can learn a lot along the way. Check out our Intro to Circuit Bending to get yourself started.

19 thoughts on “Circuit Bent CD Player Is Glitch Heaven

  1. There is two pins if shorted when powering up will make the disk spin backwards and another glitch that will make the disk spin at its fastest.
    Something that gave distorted output that looked like PWM I think I recall… but then my memory starts fading about here…
    Something unlikely about extra-extra-bassbost (But this I’m not sure my memory is tricking me).
    There are other useless glitching facts I knew but forgot about this CD player and this is assuming same chip revisions as well.

    It has a line out and a headphone out, a hold switch on the side next to another function switch that I also forgot what it is for.

    That is about 7 to 8 years ago I remember that from and I never would of thought it would interest anyone else… Found out today I was wrong :(

    Still nice to know someone else are enjoying these glitches.

    Now I will finish reading the article and watch the video so I can see, relive and relearn the glitches of this machine.

    (note to those who call me BS… Remember you just read that my memory on this is vague at best so there maybe errors and mix-ups, but I do remember owning one of these and glitching it by the time MP3 players were the in thing)

    1. Just watched the video..
      I forgot about that whimpy beep sound when stopping the CD.
      I also Not sure if my old one had a magnetic spindle stay or was a clip mechanism to hold the CD on. (I’m guessing clip mechanism due to my lack of memory).

    2. If you messed with the motor controller then you’d get weird things like incorrect rotation direction and unstable speed control. I’ve had issues before when repairing a CD player because I hadn’t replaced the metal shields and interference caused it to do bizarre things like that. I was about to junk the unit before I tried replacing all the shields which made it work perfectly.

      Sony and the other various manufacturers have made significant revisions to the electronics for those players over the years so your memories of messing with a Sony Discman player only really apply to the specific model you had at the time. A newer or later model was quite likely have to completely different electronics. The early ones were jammed full of circuitry and everything was spread out across many big ICs so you could get at the raw data fairly easily. The later ones just had a couple giant ASICs that did everything from controlling the motor to the EFM decoding to the DAC. Those were harder to repair or modify because most of the interesting signals were buried inside an ASIC and would never leave the chip.

  2. Nice neat build, and it works very well, but the sounds it makes are very ugly. I wonder if a few cheap digital delay chips could have given it that little bit extra that it needs to be musical?

          1. Actually, I think Sir Malcolm Arnold has it here with his 1956 classic “A Grand Grand Overture” which features 3 vacuum cleaners and a floor polisher.

      1. Sorry clay, I have to disagree with your opinion. My opinion is that circuit bending is the artistic equivalent of dumping in someones yard and calling it a work of art.

        Some of the sounds it made were ok. but in true circuit bending style, it ended up just being noise.

        1. Sure, most of what we heard was crap, but think of this noise as part of one percussion instrument, not the whole sound of a band. The root sound of a snare drum is white noise, but when each beat is shaped in a pleasing Attack-Sustain-Decay-Release envelope, it adds a good sound to a song.

          1. The thing about music is that it is structured, that’s what separates it from noise. I’m sure there is some decent circuit bending out there (maybe?) but I have yet to encounter anything that makes that leap.

            I’m lucky if I find something that doesn’t come off as someone outright torturing a Furby/Speak&Spell.

  3. My compassion goes to the totem-pole output MOSFETs, once working side-by-side like brothers, now forced to fight against each other whenever their address lines go shorted. Ruthless cruelty against silicon.

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