x0xb0x CPU Upgrade, x0xlarge, Gives Your Synth A Bigger Brain

This video, via Paul Rogalinski, demos x0xlarge – a x0xb0x CPU upgrade that gives the Roland TB-303 clone a bigger brain.

The CPU upgrade lets you load custom firmwares that add new features to your x0xb0x.


  • Atmega 2561
  • 256k flash (16k on the original cpu)
  • 8k sram (1k)
  • 4k eeprom (512b)
  • pwm
  • 8 channel a/d
  • Plug and play on most x0xb0x synths

See the project homepage for more info.

9 thoughts on “x0xb0x CPU Upgrade, x0xlarge, Gives Your Synth A Bigger Brain

  1. What does the upgrade actually do?
    Just watched the video, folowed the links and unless I am half asleep (it’s very possible) absolutely zero info regards the practical nature of this ‘upgrade’ . This talk of ‘firmware’ without any practical explanation of what the chip offers?
    Can anyone help, the adafruit site said zero also.

    1. The project is just for the CPU which they state the improvements, more flash space and faster processing. They link to a few different modified firmwares which themselves list their features. I would imagine new firmwares will be created now to take anvantage of the improved chip but they don’t exist yet.

      1. Thanks a lot for that , I thought it was just me. My xoxbox decay really doesn;t do a great deal ,
        does anyone else have that issue? I bought a bass bot tt 303 and I am very very pleased with it .
        I just gigged with the pair of them xoxbox and bass bot , was very good having the two , they are quite different. Inspite of the flaws in my xoxbox, it is a great simple clean and tidy synthesizer with the bonus of accent . It doesn’t have to be used in the cliched acid way , it cuts thru a mix beautifully (whats the deal with decay) Keeps music freaky and funked up.
        Chicago, Manchester, batley and Detroit., ACID

  2. I think Id rather get a korg volca bass and not risk damaging my existing xoxbox for an upgrade that reflects the quality of their ability to inform/convey information

    1. Huh? It’s just a drop-in replacement microcontroller. The new chip has more onboard memory. If you don’t like the updated firmware, you can simply reinstall the old chip and life continues on as before.

      1. I mostly sequence the xoxbox from a cirklon. So this probally isnt anything that would add more functionality? If I could controll everything via CC… then we are talking

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