Open source hardware may not sound like something that would produce a huge musical hit – unless you’ve met the x0xb0x. A clone of Roland’s legendary TB-303 bassline generator, the open version offered not only greater afford-ability than the now-rare antique, but expanded possibilities for hacking the hardware into a musical device you could love as your own, all with the backing of an impassioned community. The gadget was designed by Limor Fried and an unidentified “crazy German engineer” who has kept his identity private. (I wish I had my own secret crazy German engineer. Darnit. Any volunteers?) The resulting design has been marketed by Limor’s adafruit shop. The only downside of the x0xb0x’s awesomeness? It was something of a victim of its own success, with rare parts a challenge to find and an ongoing waiting list of pent-up demand. After shipping 900 units from 2005 through the beginning of this year, adafruit announced it was dropping sales of the x0xb0x.

But the story doesn’t end there. Aside from ongoing efforts by the x0xb0x community in general, one figure has stepped forward to lead sales of the project and (most exciting to me) generate new projects that share its open license and build on some of its components. As announced on adafruit (via Synthtopia), x0xb0x community member James Wilsey is launching a new design and sales effort.

My goal with Willzyx Music is to keep supplying the x0xb0x community with Parts and Kits. I have spent the last year building up a stock pile of parts and will bring the Kits back at an affordable price. Any new projects that are produced from Willzyx will have the same MIT open source license, so you can hack, modify and commercialize any of Willzyx’s original designs.

James is no stranger to the x0xb0x community, having sold his own completed kits as bitcrusher76. But his vision is, refreshingly, even bigger than the x0xb0x: he hopes this could lead to other open projects with shared resources. With the growing quantity and quality of free hardware and software projects, many with shared goals and features, I think now could be a great moment for the larger open source music ecosystem.

The new store:

Price for a kit is a very-reasonable $185.

And for more on the x0xb0x project:
x0xb0x Forum @ Adafruit

I asked James to answer a few questions about the project for CDM.

The x0xb0x takes its place in hardware history. Photo (CC-BY-ND) Roman Filippov.

Peter: Looking back at the x0xb0x’s first half decade, obviously it hasn’t been an easy piece of gear to get. Was it just not a goal to make it more widely available?

James: I think this is a big misconception among a lot of people involved with the x0xb0x. Adafruit made something that had a huge want factor. If you were at all interested in synths, a TB-303 clone was something that you have been dreaming about for a long time. So in 2005 a huge flood of people come and there was just no way that they could keep up with demand. They killed themselves to get 1,000 kits out. The way I look at it is this: They made a TB-303 clone that kicked ass and everyone wanted it.

That’s where I came into this. For the last year I have been selling complete x0xb0x’s on eBay and was very successful with it. I was only able to do this because of the open source nature of the x0xb0x. I started talking to Adafruit and it became clear that I have the time and resources to get the x0xbox out to as many people as possible.

Peter: What does this mean for availability of the x0xb0x?

James: If we are talking about kits, they will be coming back very soon.

Will you be accepting preorders?

Perorders scare the crap out of me.

I think demand is manageable at this point and I am not the only one selling kits. If you really want a kit you can find one if you poke around on the adafurit forums. The kit will be coming very soon and I should be able to keep up with demand.

That sounds great. So you’re looking at working up new designs, as well?

Really all I want to do is expand the firmware, I want a few LFOs and some more CVs and gates. We need to look at a new microcontroler, but its all pretty doable. The only downside is we are going to be dealing with SMDs which can be really unpopular in the DIY world.

I see listed on the site a separate item that’s just the “rare parts.” Is that idea that people could source the more common parts, then get the rare ones from you?

That is correct, the rare parts have always been a road block if you wanted to self-source your own kit. There are quite a few situations where it doesn’t make sense to get a full kit.

What’s your own connection to the x0xb0x? Do you use it in your music?”

I have always wanted a TB-303. My first attempts at making music were with Re-Birth. So that sound has always been a part of my music. When the x0xb0x first came out I had to have it! I have been in love with it ever since.

Any plans for the future of the x0xb0x?
My first priority is to keep the kits available but I am looking at the x0xb0x as a open source hardware platform for other synths that are not necessary TB-303 related. The analog synth business is very grassroots. There has been a big boom with small synth makers that might only do a run of 50 or 100 synths. It would be cool if they could just copy and paste the digital section from the x0xb0x. I am not too sure what this is going to look like but that’s the direction that I will be pursuing. Of course any of my designs will have the same MIT open source license that the x0xb0x has.

If people want to help out, what can they do to get involved?
Make and sell kits, hack the firmware, do mods but make it available to every one. Transistorize The World!

But is it as good as a 303?

I like the fact that the x0xb0x could be hacked as an entire platform, but since I missed it when picked up by Synthtopia in February, here’s a shoot-out between the open hardware and the original Roland piece.

  • AO

    Good to hear!

  • Chris Thorpe

    Sitting here fantasising about building a semi-modular using the sequencer from the x0xb0x and a MFOS Soundlab Ultimate… it would be a great live rig

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  • pillowtalk


  • reptile

    I am ecstatic that someone is carrying on this project, however a caveat or two:

    The reasonable price of $185 is not a full kit that you can sit down and build. As noted on the site, "please note that this is NOT a full kit." What is not obvious is the spreadsheet of ~100 additional non-rare parts that must be purchased.

    Once the non-rare parts are purchased (from at least 3 different sources and with a bit of work finding substitutes), the price is around $400. The full kits will probably be less if you can wait for them. Certainly less hassle.

  • @reptile, yes, fair enough. Parts include –"x0xb0x PCBs with rare parts, 2 Thermistors, Main panel, IO panel, Grayhill encoders and ATmega162 Programmed Microcontroller."

    Still a pretty good deal, but you're correct, the total price is significantly more. I think the next question is whether those additional parts can be bulk-ordered, which would bring the price down, too, if people got together and did a group buy.

    For this reason, though, cool as the x0xb0x is, I remain interested in really low-end hardware options that use all readily-available parts, because you could have ATmega-powered musical instruments at very, very low prices. And not that the x0xb0x isn't worth the investment, but then you might be more willing to really hack away at something, if it didn't set you back a few hundred bucks.

  • Machines

    I was wondering what the total cost would be. Thanks for getting that out there, Reptile. I'd very much like to build one of these, but being a first-timer, I think it might be a little beyond what I'd initially be capable of. And as Peter said, I'd be more willing to hack away at something that didn't set me back a few hundred bucks. Anybody have good recommendations on where a budding hardware enthusiast might start?

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  • aaron

    machine: try something small first.. like the YM_Mini synth @ straytechnologies or something, then work your way up

  • Josh Brandt

    Putting a quick list together from the BOM list on the willzyx site, I got up to about $100 with most of the expensive parts, the switches and knobs and pots and encoders, case, and a few other things. I think the parts should be around $200, so about $400 for the total project. Not too bad, considering, but kind of a lot of money if you're not used to building things like this.

    @Machines: The first thing is to get a decent soldering iron. You don't necessarily need a $200 Weller iron, but you shouldn't go for the $10 Radio Shack irons, either, unless you're willing to spend a lot of time annoyed and possibly cook some parts. has a toolkit which would probably be a good place to start– it's $100, but it's all stuff that you'll either need (a good iron, a meter, wire strippers, cutters, pliers) or will be glad to have (a solder sucker, a vise to hold boards you're working on). And they have a little kit to build, so you can do something easy and get started…

  • Justin Reed

    I have been on the waiting list for the OG xoxbox but chickened out when my # came up!
    I'll be honest the building scares the heck out of me. the kit from ladyada was $300 – how are these setup for $180?

    man – do – want

  • Justin Reed

    ooop, sorry reading through notes is not my strong suit. $400 sounds about right. still it's a bargain compared to the 303. i actually think it's a sexier piece of kit than the toy-looking 303.

  • Machines

    @Aaron, Josh:

    Thanks for the recommendations guys! Much appreciated.


  • rhowaldt

    '303… x0xb0x… 303… x0xb0x…' haha.

  • Incredibly cool.

  • Bob

    And all because Adafruit just could not be bothered any more. So wiped the entire waiting list of well over 1000 people. Then gave the GREAT news that they could go buy it somewhere else as an incomplete kit instead. Err, yeah, thanks?
    Fact of the matter is, you have already been able to buy them from somewhere else. There are several people that will sell you a new kit or completed x0xb0x already. For example. Only €299 for a complete kit! Or €499 built.

  • hayho

    yeah it was obvious they sold all their stock a few weeks back. Funny that they never mentioned kits have been available from many other reliable sources for quite a while. The more the better.
    check out the x0xi0 mod kits do a google search they are awesome.

  • lo_phi

    Chipforbrains on ebay

    has parts available as well as fully assembled really units. They seem much better with the power switch :0
    and cooler knobs for sure.

    They also seem to have panels, and other kits.

    The quality seems top notch. I've been a long time synth parts customer and their parts are great replacements and so cheap!
    But it would go to reason that a vintage synths parts company would be able to bring better solutions. Adafruit always had the worst service and their panels. I got first one from adafruit that looked like some kid stenciled the labels on. I tried to return it but they always just kept telling me support was on their forum?

    has something new a modified x0xb0x…
    $480 for a full kit or you can get parts to modify your b0x you already have… The I/O kit adds audio and control voltage inputs & outputs to the rear panel. It also add a complete overdrive & distortion circuit. (ala devilfish for a 303)