OK let's start with the background info...
*lights a campfire and sets up chairs*
At the University of Alberta here in Edmonton there's a big building which houses the NRC, the National Research Council of Canada. It's home to several laboratories all doing cutting edge high tech research on behalf of the government. One of these laboratories is called NINT, the National Institute for Nanotechnology. (Nanotechnology is working with materials on an atomic or molecular scale, the tiniest building blocks of matter and energy.)
The team of chemists/physicists at NINT have been working on a new kind of molecular diode for the last several years, a diode that's formed by a single atomic layer of a conductor on a substrate. Called a molecular junction, it has special properties over a regular diode. They have cutting edge applications in special video displays, sensors, high frequency info.. nanotech kinda stuff. But the lead researcher involved, Dr. Adam Bergren, is also a guitar player and realized that the special properties of these molecular junctions, such as their smother/more gradual onset of clipping, would also benefit a guitar signal. To really show the effectiveness of the molecular junctions they decided they'd need a guitar pedal prototype. And part of the NRC's mandate is to support local business whenever it can, so Adam did a Canadian guitar pedal maker search and discovered that Dr. Sci was also in Edmonton!
So back in October of 2013 Adam contacted me to see if I would have any interest in learning more about the junctions and their future. Small aside here but I am a man of science, I believe in the Scientific Method, and to be contacted by a laboratory of the NRC just completely blew me away. I'm still getting over the shock of that first email! As an EET, there's maybe no cooler gig than to make prototypes for a laboratory, it's a dream come true really for a science/physics kinda guy.
Ok, so they need a prototype! I spent a bit of time setting up a breadboard with some simple circuits that could show the molecular junctions off nicely. We bounced around some ideas and settled on this:
This is the bread-board version of the final prototype, it's a circuit that shows off the molecular junctions through the most popular and common amplifying devices: a MOSFET, an NPN transistor, and an op amp. Each device is a single gain stage and they go from high to low, the FET is a dirty boost, the NPN is a medium gain fuzz, and the op amp is a high gain distortion. Each gain stage has a gain control and then there's an overall treble control and a master volume. It's buffered in and out so it's not as susceptible to external variations and performs consistently.
For each gain stage there's a rotary switch that selects between 2 junctions, silicon diodes, or no diodes, so the junctions can be quickly compared to other popular diodes or no diodes, all socketed for experimentation. There's LED lights for the gain stages and the clipping stages so one can look at the circuit quickly and tell how it's set.
This is the mockup I proposed for the build:
The NINT team liked the prototype circuit and commissioned us to make 4 of them. I designed a custom pcb for it that looks like this:
And this is what it looks like built:
See the big black SIM card holders at the bottom right of the pcb? That's where the molecular junctions are, there's 2 junctions on each SIM and 1 junction is like a back-to-back pair of regular diodes.
These are the finished builds:
The finished protos had to have really accurate logos for all the organizations involved and this was Tanya's contribution to the project, this was a really tough job to do so small in vinyl:
And here's one lit up:
So the big question, how do they sound? Well, you guys know I'm not one for using a lot of terms like 'warm overdrive' or 'natural tube breakup' or 'transparent overdrive', I'm not really that guy.. but the molecular junctions have an unarguably noticeably different sound than typical diodes. First thing you'll notice is they keep the same level regardless of the saturation, they don't drop in volume. And then you'll notice that they really do sound natural and pleasant, smooth and warm, while also having an interesting character. They actually can make me use words like that! The 1N4148 diodes so commonly used in so many overdrives through the years sound very harsh, brittle, thin, and sizzley compared to the molecular junctions. I think the junctions have a unique quality to their sound too, they're really quite interesting.
What's so powerful about them as well is the fact that they can be tuned to emphasize or de-emphasize a number of characteristics depending on what materials are used for their conductive layer and substrate. Like they can be very mildly saturating or quite aggressive sounding. They can also sound different too by accenting or decreasing certain frequencies.
So what's the future of molecular junctions? Well that's in the works right now too! First they need to be manufactured in a smaller package. From there the plan is for Dr. Scientist to hopefully get the first license in place and do the first production run. I don't know when that will be, I don't know what that pedal will be like, and I don't know how much it will cost.. but we're working on all that and I'm beyond excited about it. Beyond that, the goal will be to be able to license these junctions to everybody and builders will be able to have proprietary junctions in their circuits, sounds available only to them. These are big plans for NINT and the NRC and we'll have to see how all that goes, I don't really know any more than you guys now.
I'm hoping that the esteemed Dr. Adam will chime in with his thoughts and correct all the mistakes I've made in describing his work. The particulars of quantum mechanics can be hard to describe well.. we all watch Big Bang Theory and know about Schrodinger's cat and the ol' double slit experiment.. but the real workings of these junctions and the quantum tunneling involved will be way better explained by a pro.
So fire away if you have any questions and I'll answer what I can and ask Dr. Adam for help when I can't! *smile*
And thank you so much to Adam, NINT, and the NRC. Working on this project was a dream come true for me and truly an honour and a privilege.
phanta ^
