The curves above can be done with a Arduino board, a solderless breadboard, a dual Rail to Rail Input/Output Op amp, a few resistors and capacitors, and some free software. The graphs above are produced by either Scilab or Octave. The curves are also viewed when using the Processing application.
This is cool, it’s called a curve tracer (not analog test interface). We used this kind of tool to spec out the x0xb0x transistors
Yesterday, I posted on the blog about Korg releasing the schematic for their Monotron Synthesizer to the public. For those who don’t know, the Monotron is a small, inexpensive ($60) analog synth. It doesn’t have a “proper” keyboard, but rather uses a ribbon controller with a keyboard layout printed on top. It’s pure analog, with 1x VCO, VCF and LFO circuits. Users have found it to have it’s own unique sound, and to be very responsive to circuit bending.
Now, lest you think that this schematic was just a leak, I’d like to point out that it’s clearly labeled “FOR PUBLIC RELEASE”. This, coupled with the fact that the Monotron’s PCB has labels for various CV points, makes it pretty clear that Korg intended to enable, if not directly encourage, users to modify their Monotrons.
As news of the schematic has spread through the DIY synth community, I’ve enjoyed reading the responses of users. I think you will too.
From @bencc: “Awesome – more companies should do this.”
From @ezod: “If @KorgUSA weren’t already my favorite synth manufacturer, they are now!”
From @larrylegend: “The Monotron was already a super cool move by Korg. And now they just released the schematic to the public. I love it!”
From Luka at MuffWiggler: “i like it how korg are publishing the schematics and somewhat endorsing the modding of this machine.”
From jellyjim at SoundOnSound: “That’s a pretty unusual thing for a large corporation to do … interesting. Of the big three manufacturers (Korg, Roland and Yamaha) I think Korg are making all the most interesting moves just now.”
From Tadas at RetroThing: “That does it! I’m buying one. Love companies being positive about hacking their own products.” (emphasis mine)
And from James Grahame at RetroThing: “Korg’s move is in stark contrast to Microsoft’s dire warning that they’ll work with law enforcement officials to prevent people from tampering with their new Kinect controller.”
Thank you, James, for making the point so well. While Korg has garnered appreciation, good karma and, most likely, increased sales numbers from their efforts to open up their hardware, Microsoft has… well, y’know…
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… Read more -
Adafruit is thrilled to be working with Willzyx Music, the x0xb0x is back. In our previous post & announcement we let everyone know that we would unable to support the project in the best way possible and we would be figuring out what we can do to help people get kits again. So, big news – we were very lucky enough to find someone who can devote the time, resources and support to x0xb0x – Meet James of Willzyx Music, he writes -
I just spent the last 10 years working in a San Francisco music shop and I really liked my job. I loved that I was helping people make music and that’s something that I still want to be a part of. Me and my wife have been making plans on moving to Taiwan for a number years and in 2009 we took the plunge. During 2009 I was selling completed x0xb0x’s on eBay under the name of bitcrusher76, it was a success and I am continuing on with the opening of my new web store willzyx.com.
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.
We want to thank James for being part of this with us and we’d like to thank all of customers, fans and everyone who has made the x0xb0x one of the best open source synth projects – LONG LIVE x0xb0X.
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 retention policy for this list is as 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 respect your privacy. We hate spam…. We will have more updates soon in the next days and weeks, we wanted to post this up as we updated some of our pages and re-did our inventory.
We have another run of 100 x0xb0x kits in the shop. If you missed a previous run, you have 7 days to email support@adafruit.com before we close the old list
If were not on the list before 5/14/07 do not email me, its not your turn yet
Here is a nice-n-easy x0xb0x demo video with good sound (yay), thanks to Booster69
It’s to celebrate that I’ve finally gotten off my ass and am finishing off run #7 after a vacation-y november and retail-rushed december
This is a classic circuit, but until now I hadn’t gotten around to building one. Its useful whenever you need a floating supply or if you need a quick way to poke a signal voltage into a circuit. (I suggest it for people building and testing x0xb0x’s)
I installed Arduino IDE 009 since I figured I should learn this stuff if I’m going to sell Arduino’s (and clones)
My project today was to build a simple NPN Hfe (Beta) meter to do some tests on the now ultra-rare 2sc2291 matched pairs. My multimeter has one but I wanted to make sure I was testing with the same setup as the one in the datasheet, with a Vce of about 6V and Ic = 1mA. The results are in the x0xd0x wiki
This is the breadboard circuit I used:
its similar to the one described on the x0xb0x page, but with the op amp swapped around for NPN’s
The sketch is rather small, I just take the two analog measurements, do a bit of math and spit out the calculated beta. I checked this against my meter and it matched up for lower betas (although not for higher ones, which may mean I’ve got current leaking into the opamp)
A teaser from Misusage (who made the awesome TileToys a few years ago)…a cute circuit idea to automate knob tweaking! Microcontroller + digital pot + glue = MemPot, a speed-adjustable programmable ‘memory’ potentiometer. Seen here manipulating a modded x0xb0x, yum!
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