You’ve been asking for this for a long time now. A gift to the Roland aficionado. Finally, a Roland 13 Pin Adaptor for the Nu Series Modular Active Pickups.
- CH1-4 – Nu Multi Channel 1 to Channel 4 In
- CH5-6 – Nu Multi Channel 5 to Channel 6 In
- 1 & 2 – 13P FPC Receptacle
6P Male Headers
- S1 – Switch 1 Input
- S2 – Switch 2 Input
- GND – Ground Pin
- MONO – Guitar Mono In
- GK-VOL – Volume Control
- GND – Ground Pin
2×4 Male Power Pins
- GND – Ground Pins
- 5V – 5V Regulated Power Pins
- -VE – (-)7V Power Pins
- +VE – (+)7V Power Pins
Gone are the days of DIP (Dual in-line) ICs. Most modern ICs are no longer offered in easy to use 2.54 mm (0.1 inch) pitch packages. The descendants of DIPs, the SOIC (Small Outline IC) and its friends (e.g. the TSOP (Thin Small Outline Package)) are shrunk down to 1.27 mm (0.05″) and even as low as 0.5mm (0.019″).
So how do we prototype using such tiny critters? We do it using the Dead Bug approach: A free-form construction, point-to-point soldering, often with the ICs flipped upside-down with their pins sticking up into the air like dead insects. The components are constructed, ad-hoc, using a bare copper-clad board serving as common ground. This construction technique drastically reduces electrostatic noise compared to other prototyping techniques using perf-boards or bread-boards.
Soldering a tiny TDFN-14 0.5mm package!
Dead-bug constructions are typically ugly beasts! We use a variation of the technique called the Manhattan Dead-bug Style, using small pads punched out of copper-clad board and glued into the main copper base. The pads serve as islands for soldering circuit nodes.
High efficiency Class-D amplifier
I like modular, reusable building blocks. And so we build small modules and connect them together, all on top of another bigger copper clad board. This construction is very favorable to noise sensitive electronics. The module you see here is a high efficiency Class-D amplifier.
Time to revisit the Alpha and replace Alpha’s pickups with what else but Nus and XRs! Dimarzios out, Nu and XRs in… Ehmm, OK I suppose I’d refret the guitar as well.
In case you have no idea what Alpha is, check out this link. Alpha is a thru-Neck Carbon Fiber over Bamboo with a Carbon Fiber Body I designed and built a few years ago. I’ll have more of Alpha in the coming days. Stay tuned. I am highly considering building a few of these sexy Carbon Fiber guitars with even crazier ideas brewing in my mind over the years, perhaps in collaboration with a fine luthier in the U.S. or in Europe (To my luthier friends: send me an email if you are interested and let us talk). You want the bleeding edge, this is it! It will be a complete multichannel system with the Nu, Nexus and Infinity all standard features, just as I envisioned it when this all started a few years ago. Yes, Infinity! My holy grail is now within reach with recent breakthroughs!
Last time, we designed a a common baseplate for the Nu and XR pickups. I think it looks good! Check it out. You have independent height adjustment for the Nu which you want to be as close to the strings as possible (within 1mm to 2mm) to minimize crosstalk. The whole thing fits a standard PAF profile.
Some of you asked if it is possible to have the Nu and XR in a common baseplate. It turns out that it is indeed possible. The way to do it is have the Nu Multi, which has a somewhat lower profile, piggyback on the XR’s baseplate. This way, the Nu will still have its own height adjustment independent of the XR. You’d want the Nu capsules as close to the strings as possible (within 1mm to 2mm) to minimize crosstalk. Here’s the idea:
The MIDI module includes a small, general purpose 16-bit MCU (Texas Instruments’ MSP430) that converts control voltages (CV) to MIDI. It is designed to be hackable. If you are adventurous enough, you can reprogram the code for your own purposes. The software is Open Source and can be cloned via Github (see Nexus repository). The code is based on the ubiquitous Arduino platform to make it easy to hack into.
You need a programming device to update the MCU Module firmware. There’s a lot of MSP430 programmers available out there, but the question is. “What is the cheapest we can get?”. Answer: the MSP430 launchpad dev board from Texas Instruments. Dev boards from chip manufacturers are often heavily subsidized, making them very inexpensive. The table below shows the price comparison for a few MSP430 programming devices including the MSP430G2 Launchpad Development Board.
What we need:
- Nexus MCU Module
- MSP430G2 Launchpad dev board
- Female-to-female jumper wires
- USB Type-B mini cable
Step 1. Remove all header shunts
Carefully remove the shunts highlighted on the dev board. RX/TX pins should also be removed to avoid data collision when programming an external MCU.
Step 2. Connect the jumper wires to the Launchpad
Follow proper jumper wire color coding indicated in the pictures below.
Step 3. Connect the jumper wires to the MCU Module
Step 4. Connect the USB Cable
Step 5. Install Energia IDE
Follow this link for Mac, Windows and Linux installation guides.
Step 6. Download and clone the firmware
Follow this link. You can download or clone the repository to your local drive.
Step 7. Flash the Firmware
- Open the source file using the Energia IDE.
- Click upload.
- Wait until the app indicate finish upload without errors.
Time flies! It’s been almost 4 years since I last updated our Op Amp Shootout page. Now It’s 2017, and this page is still our top hitter. I guess that only means that people find this page helpful. And I am always happy to share information. I’ve updated the page to reflect recent developments. I always have a keen eye for new Op Amps and the new additions (shown in light purple) were taken straight from my notebook.
There are some interesting additions such as the OPA188 with a wide supply range of 2V to 18V, and very low 500μA current consumption. I also added a bunch of very Op Amps from Japan with rather respectable specs. Check out the NJ series Op Amps from JRC New Japan Radio Co., LTD. I found out about these cool Op Amps from studying Roland schematics. Have a look at the NJU77806, for example, with a noise figure of 5.5 nV/√Hz at 1kHz while consuming only 500μA.
There are also retirees. For example, the ultra-low noise LME49990 has reached its end of life. But there is certainly a new audio Op Amp king of the hill: the LMH6629 with a super impressive 0.69 nV/√Hz at 1kHz noise figure! The LMH6624 takes second place with very respectable 0.92 nV/√Hz at 1kHz noise figure.
Interesting tidbit: In that page, Mark Norton commented: “I feel sorry for all of you using op amps. Sterile squinching of sound imho.” He’s obviously not a fan, but then I had to reply: “I feel sorry for you believing such myths :-)”. Op Amps: Myths & Facts. The funny thing is, all forms of modern recorded music would have gone through dozens if not hundreds of Op Amps in the signal chain, through the recording process (EQs, compressor, limiters, etc.). If “sterility” means not degrading the purity of the sound (e.g. preamps), then I suppose that is good. But “transparency” is a better term.
Now go and check out the updated Op Amp Shootout page.
This is the fourth part of the Nexus documentation series. The first part documents the Basic Kit, the second part details the Mixer Module and the third part, the MIDI Module. This time, we explore In-Guitar Control and Connectivity —stuff that you install in your Nu-equipped guitar. Eventually, all of this will end up in a single document.
With up to 12 channels of Audio, the Nexus offers a lot of versatility. There are many ways to set up your guitar with a Nu multichannel pickup alongside other standard monophonic pickups such as the Cycfi XR active pickups.
But how do you control an N-channel system? Take the master volume for example. Adding a master volume to a traditional monophonic guitar is easy. A simple potentiometer will do. For an N-channel instrument, good luck if you can find an N-ganged potentiometer. Or how about switching? How do you switch N-channels? The traditional Strat-style 5-way switch and 3-way Les Paul toggle switch will no longer be adequate. The most versatile solution of course is MIDI. Use your external gear (or DAW) control master volume or patch settings or just about any parameter you wish.
Control voltages may be sent along with audio through any of the 15 channels via a LEMO compatible connector. Control voltages come from specialized potentiometers and switches. This will be converted to MIDI messages in the Nexus.
Here are some factory images of the first Nexus batch. We’re building a system! And this system is going to be awesome!
Merry Christmas, Everyone!
Parts for In-Guitar controls and that gorgeous 19-pin multichannel connector.
This is the third part of the Nexus documentation series. The first part documents the Basic Kit, the second part details the Mixer Module. This time, we explore the MIDI Module. Eventually, all of this will end up in a single document.
The MIDI Module converts control voltages (CV) from the guitar to MIDI. The basic firmware supports up to 6 analog and 7 digital inputs. The Multichannel Guitar Input (see Basic Kit) can carry up to seven control voltages or switches. Some of the back panel 1/4″ jacks may also be repurposed to carry additional control voltages or switches. The MIDI output is sent through a standard 5-pin DIN connector at the back panel.
Note: Please do not be confused with MIDI control and MIDI conversion. The MIDI module does not do any pitch tracking and MIDI conversion of the notes.