"Interesting" Canadian clipping research project

[Mark Hammer]

...and done at one of my alma maters!  Fascinating stuff.

http://ilovefuzz.com/viewtopic.php?f=146&t=43705&sid=232bc06f8753aaee7f54bcddfff117d7

[teemuk]

Interesting.

My approach was "simpler": A software waveform editor (CoolEdit) to which you could practically draw any kind of transfer function of input vs. output amplitude. Went far beyound the limits of choosing different types of "junctions" or "knees".

But in my experience all "practical" curves just mainly sounded "distorted", and if I didn't know any better I couldn't really point out what was "hard", "soft", "symmetric" or "asymmetric" distortion. Yes, there were different nuances to them but the overall impression was that they all simply sounded "distorted" and pretty much the same.

Fancy looking pedal though. But I wonder how many people in practice would have any use for it, aside the intented one: Demonstration purposes. It probably demonstrates that all of this doesn't in practice make THAT big difference.

[electrosonic]

Cool. I would like to see a V vs I plot to see what is different from regular diodes.

Andrew.

[electrip]

What teemuk said.  

Btw, could be based on this:

Haijun Yan, R.L. McCreery.
"Anomalous Tunneling in Carbon/Alkane/TiO2/Gold Molecular Electronic Junctions:
Energy Level Alignment at the Metal/Semiconductor Interface"
ACS Applied Materials & Interfaces 2009, 1, 443-451.

http://pubs.acs.org/doi/abs/10.1021/am800126v

Maybe there is already a waiting list on TGP.  

electrip

[electrip]

For now disappointing.
Before making demo vids one should care that amp and recording gear is setup properly.
High frequency content is overemphasized so all circuit topologies sound harsh.

electrip

[electrip]

Informative video + good sound. 

[Ben79]

This is exciting stuff - being able to HEAR variables at the quantum level.  I agree with Nick, even through a little ipod dock speaker, I could hear a sweeter tone from the molecular junction clipping - whether that's significant of any kind of inherent properties of the new technology, I don't know, but it's very interesting.

[electrip]

[Keppy]

So, back when this thread was posted, I reached out to Nick on youtube, and he put me in touch with Adam (the Canadian scientist on the thread Mark posted at the top of this page), and now, a year later, I have some molecular junctions coming in the mail. Pretty cool.

The question is, what do I do with them? There's got to be a cool application beyond just clipping diodes, but no ideas have really coalesced for me just yet.

As much as I would like to come up with something on my own so I can feel cool, there's probably a better idea to be hashed out by this forum.

Basically, a molecular junction functions much like a pair of antiparallel diodes, but with a more gradual transfer curve. See below:


I can think of plenty of uses for diodes in general. I have yet to think of many uses for antiparallel diodes specifically. Who's up for some experiments?

[samhay]

If you put a diode in series with these then you effectively have a single diode. Not sure that that helps much.

I would use them for the obvious application - clipping either to ground or in the feedback loop of something. It might not be very exciting, but this should make the most of their nice soft knee.

[Keppy]

If you put a diode in series with these then you effectively have a single diode. Not sure that that helps much.

I would use them for the obvious application - clipping either to ground or in the feedback loop of something. It might not be very exciting, but this should make the most of their nice soft knee.

Yeah, I know they're perfect for clipping diodes, and clipping diodes are great fun. With these being new technology with limited availability, though, I was hoping to use them in a way that hadn't been done yet, just to make the most of the opportunity.

Of course, the person sending these to me, who studies them for a living, assumed I'd use them as clipping diodes, so it's probably harder than I want to admit to think of other audio applications.

[Quackzed]

i don't want to be a wet blanket, but i'd think that using them in any way other than as clipping diodes would be a bit of a waste, no? after all, the soft  curve is the big difference with these diodes, what better way to hear that than using them to clip a signal? a back to back pair to ground seems like the most revealing setup, preferably driven by something extremely linear and distortion free... a simple circuit without a lot of bells and whistles to muddy their character...
i guess i see what you're saying, but i'd mostly want to hear how they clip... thats just my opinion.

[12Bass]

[Mark Hammer]

Sounds nice.  Especially when aiming for just a bit of coloration.  Thanks!

[stonerbox]

The npn gain, talk about thick and fudgy crunch.

[amptramp]

A stompbox named "Heisenberg" leaves me with some uncertainties...