x0xb0x® Your one-stop acid bassline shop
Introducing the x0xb0x

The first release candidate. Not so shabby for a kit!

Click on the panel picture for a closer look!

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!

100 b0xes of x0xb0x on the wall

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.

We have made 9 runs of 100 kits each. All but one of the components in the kit are through-hole.We had a great run and we are currently exploring how to best support this project in 2010 - so far we've made the project completely open source and we will have more updates in the month of April with what's next for our role with the x0xb0x.

Because of demand and time/cost to make these kits -starting in 2005 we created a "waiting list" where interested kit makers could sign up to be notified if and when the next run was available for purchase.This list was a "spot in line" for the kits Adafruit Industries may make based on pricing, time and demand. We did not accept any payment in any form until the kit was shipped and the listee was notified to place their order with a special password for that run. This worked out great, we never "held" funds unless a kit was sent. The waiting list was simply a "back in stock" notifier for potential x0x customers.

At this time (4/2010) the waiting list is closed and no longer will be used. Our data retinition policy for this list is mas follows -- We do not retain email addresses or names, if you signed up you can safely assume the list has been deleted, you will never be contacted by Adafruit or anyone else. We hate spam.If you have any questions please email support@adafruit.com

Before you email us with your question, read the FAQ and search in the forum. If you have a question, please ask it in the forum!

p.s. x0xb0x is spelled with two zeros.
p.p.s. x0xb0x is pronounced "zocks box"

* We don't actually do this, the instructions are all online in glorious high-def &full-color

The mainboard PCB for the kit

Case in Point

We tried a bunch of cases until we found one that we felt would be durable yet stylish. The x0xb0x has two CNC machined aluminium face places that fit into a reclosable ABS 'console' box. The top plate is also silkscreened. The x0xb0x is portable, but large enough for users to hack their own modifications in. We tried to put it in an altoids tin, no really, but it just wouldn't fit.

Engineered for Quality

We have two--count 'em, two--analog electrical engineers with too much time on their hands working on this project. An original TB-303 was diassembled and reverse-engineered to verify the schematic. The original transistors were analysed using big expensive curve-tracers to determine their characteristics. We measured every waveform and counted every cycle to give you the best sound...its just like the original because it IS the original.

We tweaked our design until they sounded exactly the same

Obsessive-compulsive? Well he is German

Our crazy German engineer obsessed over EVERY GODDAMN THING in this synth to make sure it was perfect. We sourced all of the original transistors and op-amps, even though it took months of harrassing people on the phone. Just deciding on which potentiometers to go with took three solid weeks of searching through catalogs. (Its a good thing he's unemployed or he would have been fired for not leaving the house.)

It took us 6 months, but we tracked down the original transistors: 2SK30A JFET, 2SC536F NPN, 2SA733P PNP, 2SC2291 & 2SC1583 matched pairs, LA4140 (the original headphone amp), BA6110 (equivalent to BA662) OTA, AN6562 (original op-amp)



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.


x0xb0x has all the I/O you could ever need:

DC Jack, Headphone, CV, Gate, USB, Mix-in, MIDI jacks, Line out, DIN Sync (shown w/clear acrylic panel. kit panel is aluminium!)


We added a couple extra modes to make the x0xb0x more fun than the rest

Free as in "Free your mind and your ass will follow"

The x0xb0x will never become 'discontinued,' because it is fully documented and released (under an appropriate open-source license). The PCB files (schematic, board, BOM and gerbers), firmware, software and panel DXFs are available for download. Even after we sell all the kits, you will still be able to build your own x0xb0x.

We do this because we love you.

The first revision PCB...oh how long its been...

October 17, 2011 11:30