Questions about the new synth modules - Midi, USB I/O and CV

I’ll see what I can do about setting up a project.

I just received my CV kit in the mail and I’m wondering if I need to worry about the ground. In the past I used a mini mono cable I soldered to a breadboard jumper with the ground tied off. I’ve read that the werkstatt must share a common ground by being plugged into the same mixer. Before I do any extra work or mess up my werkstatt does the CV modual cable need to be grounded?

Thanks!

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Hey @sc4r4b!

I’ve got these wise words from our R&D expert:

“Mono cables should be used with the CV module and the tip is the signal and the sleeve is grounded.”

Let us know if you have any other questions!

Best,
Patrick

Thanks for the reply! The werkstatt cable does require it to be grounded on the chassis.

Hi,

The video ‘getting started with littleBits & Korg MIDI, pt 1’ (YouTube link) shows a keyboard midi controller directly connected to the MIDI bit via DIN5. That doesn’t work for me.

When I connect my keyboard controller directly to the MIDI bit via DIN5, the behavior is as if the ‘note off’ signal isn’t recognized and as if not all input is received. When I send signals over USB through my Mac (using MIDI Thru software) to the USB input, I get the behavior I expect.

I’ve uploaded a short, low-fi video that shows what’s happening (here on YouTube).

I do not have a USB-B to micro USB to test a direct connection from my keyboard to the MIDI bit. But I really want to use the MIDI in because I have my eye on a little key tar that only has DIN5 out.

So, is the behavior in the video as expected or not? Do I need some interface between the keyboard controller and the MIDI bit or should a direct connection work?

Thanks for your help!

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Hi jdanke,

Sorry to hear that you’re having some issues. That behavior is not expected. Can you share what model MIDI controller you are using? I’m wondering if the issue might have to do with how the controller handles sending MIDI messages. There is a MIDI spec that most controllers follow but there are also quirky ways to do some of the communication.

Regarding your mention of a USB-B to micro USB cable, this will not work. The spec for USB MIDI requires a USB host like a computer or tablet. A USB MIDI controller cannot be plugged directly into the MIDI module’s USB input. This is true of most MIDI hardware.

Hi, Paul,

Thanks for getting back to me.

Just to be clear – I should be able to directly connect the MIDI controller to the 3.5mm input, right?

The controller is an M-audio Keystation 49e. It’s probably seven or eight years old and is now discontinued. It works fine with Garageband and whatever my son uses on his PC. I also ordered the Rock Band 3 keytar ($30) because I read that it’s a decent controller and it would be a good base for an “on-the-go” synth platform. Plus, it gives me an opportunity to test another MIDI controller inexpensively,

I’ve ordered a new MIDI cable to test whether that is the problem. I might have to solder my own DIN to stereo. I found only one DIN 5 to 3.5mm stereo cable, but it’s wired incorrectly, using pins 2,3,5 instead of 2,4,5. (see below).

Joel

Incorrect wiring from kenable:

Hi Paul,

It turns out that your suggestion about the controller is right. There’s something about the older M-audio Keystation 49e that just isn’t working.

I received the Mad Catz / Rock Band 3 Keytar today, plugged it directly into the MIDI module via the 3.5mm input jack and it works exactly as expected. Pretty good deal.

Thanks for your help,

Joel

Hi Joel,

I went ahead and ordered a midiman Oxygen8 controller from eBay which is the same era as the Keystation you have. I can confirm erroneous behavior when connecting the controller to the MIDI module. I have not seen this with other controllers we’ve tested.

I have a theory as to the issue and will write again once I have more information. It may be an incompatibility with some of the MIDI messaging protocols that were used at that period of time but have since gone out of implementation.

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Also considering getting Midi or USB I/O to use with some older gear, and didn’t understand the basics from the description in the Littlebits shopping page. Apologies in advance for beginner questions:

  1. When I think of MIDI interface, I think of the old 5-pin DIN connector… Is that the same thing as MIDI today, and if so is there an adapter for gear using 5-pin DIN? Does the MIDI littlebits come with an adapter? Confused because the MIDI littlebits has two inputs (MIDI in and usb i/o).

  2. M-Audio Radium 49- I’d like to play on this controller to the Littlebits (oscillator, etc). It has MIDI out (5-pin DIN) and a USB port (for Garageband, etc.). Which one do I need, MIDI or USB I/O? If the MIDI littlebits, what adapters do I need and which port (MIDI in or usb MIDI i/o) does the keyboard controller go in to?

  3. Roland Sound Canvas (original SC-55 from 1991)-- Same question as above… this only has the 5-pin DIN MIDI ports, how do I physically hook it up to the MIDI Littlebits? (what else do I need to buy)?

Many thanks in advance! Sorry again for the basic questions.

Hey guys! I am having a hard time properly controlling the little bits synth kit with my Qunexus. I have it connected to my cv module and when I play a note it turns the gate on but does not turn the gate off (note sustains infinitely). I add the envelope module and nothing’s comes out, no notes at all. I think I need a separate cv gate module to turn the gate off but wondering if there is any way to do this with just the little bits synth kit. I don’t want to purchase a 3rd party module just to play this thing. Any thoughts?

Hi @Justin_Michael_Mille,

So, from the way the Qunexus outputs CV, this is exactly what I would expect to happen. The Qunexus multiplexes the gate and pitch CV signals onto a TRS connector, with the pitch on the tip. The CV module only cares about the signal on the tip of the TRS (see for yourself).

Right now there is no official (read: dedicated bit) way to connect an external gating signal into the littleBits system. The control voltages that the Keyboard module produces are actually kind of a hybrid pitch-gate combination; they turn on to the correct pitch when you press a key, and drop to zero when you release it. Unfortunately your Qunexus doesn’t output CV the same way.

If you’re up for a little hacking, there’s a way you can get around this. You’ll need a Y cable plus two regular 3.5mm cables, stereo or mono. Cannibalize one end of one of the cables so you have two exposed wires, one from the tip and one from the sleeve.

Build this circuit:

power > CV > oscillator > envelope > [whatever else you want] > speaker

Connect your non-cannibalized cable from the Left output of the Y cable to the input of the CV module. Plug the cannibalized cable into the Right output of the Y cable. Connect the exposed wires to a proto bit (either of the two screw connectors, make sure the 3 jumpers are all in place). Connect the tip wire to the middle screw terminal, and the sleeve wire to the screw terminal on the side that says GND. Snap the output of the proto to the “trigger in” bitsnap on the envelope. Voila, you should have a gated CV signal.

This is the best method I can think of until we get a gate bit (hopefully soon!)

-Sam

@Justin_Michael_Mille Addendum: If you can find a Y cable that’s a male TRS 3.5mm to 2 male TS 3.5mm, you can use that and not have to use any extra cables… but they seem to be like unicorns, with the sole exception that two are actually included in the Qunexus “cable kit” accessory. Maybe you already have that, in which case, awesome (if you’re willing to cannibalize one side of one of those cables).

Hello fellow forum members,

I’m a bit of a newbie to the little bits synths
i was wondering if these ‘connectors’ would make for a Midi (in) to CV (out) converter -
i have a Korg MS-10 i would love to sequence via Midi, so maybe the little bits would help
(Most of the tutorial videos online show these connectors in relation to other parts of the little bits synths, but do they also function when connected without a little bit synth in between )

Yes they do. See the link below where I used my iPad to control a moog werkstatt.

Power Bit > USB MIDI bit > CV bit out

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Hi,
I had the same problems with the Midi module. No note-off. It is indeed the Midi protocol used by older machines. First I tried to connect it with a Yamaha DX100 and my Yamaha QY700 Sequencer. The DX gave no note-off to the or just every now and then. With the QY it worked a little bit better, when I played a sequence. It kept the littlebits busy enough, I guess. :smile:
Then I hooked it to a newer DSI synth and TADAAH it worked just as it should.
I just decided to reply, cause it took me a while to find this information anywhere on the net, so hopefully other people with the same problem will find this post.

…which was my first one on this forum, so “Hello!”. :smile:

Cheers,
michl

Hi @michl, and Welcome! :slight_smile: Thanks for sharing your findings!

I’m thinking of using USB I/O & CV to send modulation to my Microbrute filter/PWM/etc.through something like Silent Way or CV Toolkit.

Does the USB I/O board draw power from USB, or would it also need a Power bit?

You also need a power bit.

How do I connect the cv-module with my synth that uses banana jacks?

I’ve got to try this with my synth modules :slight_smile: