x0xb0x MK2

x0xb0x = Synth + Sequencer

The x0xb0x is not just another MIDI-controlled TB-303 clone. x0xb0x is a full reproduction of the original Roland synthesizer, with fully functional sequencer. The sequencer can be programmed just like the original 303 (ok its actually a little easier, we think) and can be used to control other synthesizers via any of its various output formats. 128 banks of track memory and 64 banks of pattern memory are stored in onboard EEPROM, no battery-backup is needed!

The Socksbox MK2 is the consequent onwards development of the perfect TB-303 Clone. We have improved the production flow of this model and switched the production to exclusive 100% German hand made quality.

This fact will guarantee you a much better sound by full discrete analogue signal processing. We also guarantee that our chief technician will calibrate each unit personally and by hand to sound like a real TB-303. We will not release a unit for shipping before it sounds like the “real thing”.

Additionally we have improved the quality of the pots, encoders, switches by only using components from the best suppliers, most of them from Germany.

The best 303-Clone ever made! Based on the original x0xb0x by Limor Fried, Adafruit Industries

The x0xb0x (Adafruit edition) was available as a kit that includes all parts necessary to build a x0xbox: PCB, case with CNC machined faceplate, components, buttons and knobs, AC adaptor, pre-programmed microcontroller, and (of course) poorly xeroxed assembly manual… You supplied the sweat & tears.

x0xb0x is spelled with two zeros and is pronounced “zocks box”

Pictures from the original Reverse Engeneering process by Adafruit Industries



  • 100% analogue TB-303 circuitry
  • Additional Sequencer Functions
  • MIDI in/out/thru
  • Sync Out
  • USB
  • Bankloader
  • Sokkos OS
  • CV/Gate
  • Headphone Out
  • Mix input for audio
  • Random mode: fill a pattern bank with random notes, or have it just play random notes
  • Keyboard mode: just like those casios you had as a kid. Press the keys and sound comes out!
  • Rotary encoder tempo knob: for finer control over the tempo, or you can set the tempo via computer control mode
  • Firmware upgradable: the C code is written for AVR-gcc, any Mac/Linux/Windows computer can be used to recompile new code for the x0xb0x. Reprogram using the x0xb0x software with USB. Mess something up? You can always revert back to the original firmware.

No less than 40 LEDs adorn the x0xb0x.

Computer Controlled

Plug this baby into your computer, using a standard USB port. Our Java software will control the x0xb0x, or let you save/edit stored patterns and tracks in the onboard memory.


  • Open Source OS (current: SOKKOS)
  • External Powersupply: 9V AC 500mA (included)
  • dimensions: 275 x 195 x 90 mm
  • weight: 1,0 kg




Pdf Manual: