Most interesting, versatile diode clipper/ waveshaper in distortion pedal?

[Vivek]

active diode clamp elements

Great idea to use active diode clamps in a fuzz!





However I wonder if very sharp clipping cutoff is necessary or desirable in AIAB or distortion pedals.

I was of the opinion that musicians get the "Edge of breakup" sound by having a "knee" in the clipping circuit and playing close to that knee. This leads to greater change in harmonic content with slight changes in volume.

I feel that a precision diode clamp will have zero dynamics.

N'est ce pas ?

[amptramp]

active diode clamp elements

Great idea to use active diode clamps in a fuzz!





However I wonder if very sharp clipping cutoff is necessary or desirable in AIAB or distortion pedals.

I was of the opinion that musicians get the "Edge of breakup" sound by having a "knee" in the clipping circuit and playing close to that knee. This leads to greater change in harmonic content with slight changes in volume.

I feel that a precision diode clamp will have zero dynamics.

N'est ce pas ?

True, the cutoff from an ideal diode is very sharp and non-dynamic which is why I included a variable series resistor from each clamp polarity to the junction of the two 10K resistors going from the second stage to the third.  I also included selective coupling to the junction with a variable switch giving direct, capacitive, L-C or no coupling to this point.  If you used direct coupling and 1000 ohms, that would approximate the effect of a 6AL5 dual diode.

I envisioned this device as a studio pedal that would allow you to select the preferred sound out of a bewildering array of possibilities.  I don't see it as a pedal for gigs because if an adjustment (of the eight) goes wrong, you have a gargantuan task trying to get it back to where you started.  Not to mention, you need a positive and negative supply which may be a bit of a problem.

[r080]

Not exactly diodes, but certainly interesting:

https://www.nanologaudio.com/nanolog-device-science.html

I have yet to try them. Available at small bear.

[Fancy Lime]

Not exactly diodes, but certainly interesting:

https://www.nanologaudio.com/nanolog-device-science.html

I have yet to try them. Available at small bear.

Please tell me that this is hyperbolic satire on pseudoscientific marketing BS! Did they just claim to have invented the tunneling diode only this time around it acts like a normal diode but a really sucky one with tons of parasitic series resistance only that's somehow great now? I think they did. Kudos to them balls, satire or not.

Andy

[amptramp]

Not exactly diodes, but certainly interesting:

https://www.nanologaudio.com/nanolog-device-science.html

I have yet to try them. Available at small bear.

Please tell me that this is hyperbolic satire on pseudoscientific marketing BS! Did they just claim to have invented the tunneling diode only this time around it acts like a normal diode but a really sucky one with tons of parasitic series resistance only that's somehow great now? I think they did. Kudos to them balls, satire or not.

Andy

They have been so successful at nanotechnology that they had to move to a smaller building.

[Fancy Lime]

Not exactly diodes, but certainly interesting:

https://www.nanologaudio.com/nanolog-device-science.html

I have yet to try them. Available at small bear.

Please tell me that this is hyperbolic satire on pseudoscientific marketing BS! Did they just claim to have invented the tunneling diode only this time around it acts like a normal diode but a really sucky one with tons of parasitic series resistance only that's somehow great now? I think they did. Kudos to them balls, satire or not.

Andy

They have been so successful at nanotechnology that they had to move to a smaller building.

I heard their new smaller building doesn't have a door. They just tunnel through the wall. You know, because of quantum. Only works with them newfangled walls made of molecules, mind you.

[PRR]

....Did they just claim to have invented the tunneling diode only .....

You know too much; only like a dozen of us here know what a tunnel (Esaki) diode is.

AFAICT, the voltage drop is larger, they do not show any negative resistance, and they claim it is made of Carbon which I don't think works for Esaki's diodes. My guess is that it is like the old telephone protector "carbon blocks", except FAR thinner, few atoms thick.

Joke? SmallBear sells them and the price is not funny. (Cheap if it really is a New Tone, but expensive if you can get close with some voltage scaling and parasitics.)

[Rob Strand]

Please tell me that this is hyperbolic satire on pseudoscientific marketing BS! Did they just claim to have invented the tunneling diode only this time around it acts like a normal diode but a really sucky one with tons of parasitic series resistance only that's somehow great now?

While I'm not fond of the marketing BS, they have done some *something*.   One claim is "molecular electronics"
"Where traditional diodes are made up of billions of molecules, our active Nanolog Devices are made up of 2 to 8 molecules. "

From a engineering and user perspective I guess my beef is they don't show the non-linearity in a clear way.  Obviously the voltage drops across the diodes a higher but what about the underlying shape  ie. by scale the clipping curves to be equal height.      From the crude graphs it looks like the curve is very much like a Germanium diode in series with a Silicon diode.

[MikeA]

I got a sample of the nanolog devices when they were introduced in 2017 (serial numbers 12 and 30, $75 for the pair!) and tried them out.  The designers were very helpful, but the devices don't do anything that can't be done with other diodes or combinations of diodes, and what killed them for me was (1) price and (2) their delicate nature, they won't tolerate any DC bias at all.   MikeA

[Rob Strand]

(2) their delicate nature, they won't tolerate any DC bias at all

I wonder if you can protect them with a diode in parallel to take the current?  or is it that any prolonged bias does irreversible damage?

[MikeA]

Rob, I wondered that too.  Here are my questions (in italics), and the detailed answers from Adam Johan Bergren, the co-founder of Nanolog Audio, again from 2017, so things may have changed since then.  The mentioned handout is at the bottom.


1. The handout mentions to avoid a DC bias.  Is there a DC breakdown voltage rating?

There is no real single value for this, as it will depend on how long it is applied and how large it is. This is why I recommend avoiding DC, as we've tested devices for months with continuous AC voltages with no issues.

2. What's the consequence of an applied DC voltage?  Will the device operate sub-optimally, or degrade over the long term, or will that immediately "let the smoke out"?

With applied DC, the devices can either degrade over time, becoming more linear, and eventually losing their ability to provide distortion. They may "smoke out," again, depending on how high the voltage is. The circuits I provided in the handout have been tested to at least some level, and the device should work well in these, but it would be best to avoid the potential for degradation!

3. Can I apply a DC voltage momentarily for testing?  For example, can I use a Peak Atlas DCA55 (test current up to 4 mA) or a Fluke 179 (test current ~ 1 mA) to make forward voltage readings?

Momentary testing could be fine, depending on the speed of the voltage application and the device used. In general, though, there is no reason to use a voltmeter- you will not get any useful information from that. The best way to characterize the devices is by measuring the current-voltage curves (the handout should have what these look like for each type), and we typically do this using lab-based custom build measurement modules (a typical scan from -1 V to +1 V is done at a rate of 100 or 1000 Volts per second, so the whole test is very fast), or Keithley 2602 modules, which again scan the voltage very fast (each individual current reading is done in ~0.001 seconds, depending on the settings. So, I would recommend to avoid test equipment that is not able to be controlled with very high precision- hopefully that makes sense!

4. I assume the static discharge sensitivity is in the same range as silicon transistors, since they weren't shipped in static bags.  So there's no need for special ESD precautions (wrist ground straps, conductive work mats) when the devices are outside a circuit, correct?

Static discharge has not been an issue, so as far as we know, you are correct here. I've never had a device fail due to anything like that, so you should be okay to treat them like diodes or transistors.
Overall, the best thing to do to get a sense of things is to take a circuit that either has clipping diodes in the feedback loop of an op-amp, or shunts the voltage to a reference point, and ideally with a coupling C-R combo that will eliminate DC voltages (so that there is no DC on the devices, and much like you will see in a RAT circuit as an example), and then switch between the conventional diodes and the Nanolog Devices to see how it changes the waveshape, amplitude, sound, and feel of the circuit. Most often, the circuit takes on a more interactive feel with a more rounded tone, along with a high-frequency roll-off. It has worked well in things like Boss SD-1 circuits, and I've begun experimenting with a RAT and a Big Muff, and this hopefully gives you an idea of where to go....

I hope that this is enough and useful information, and should have any further questions or if you have specific circuits that you are thinking of, do let me know!   AJB

[Rob Strand]

Rob, I wondered that too.  Here are my questions (in italics), and the detailed answers from Adam Johan Bergren, the co-founder of Nanolog Audio, again from 2017, so things may have changed since then.  The mentioned handout is at the bottom.

Interesting read.    You asked the right questions and they did answer them honestly.

So I guess the take home message is not to try your luck with DC at all.    The fact they are saying even the multimeter isn't recommended means "degrading over time" could be a fairly short time.   Their rapid test set-up implies the same - not cheap equipment nor the type of test that's easy to do with DIY'er equipment.

They say to keep the voltage below +/- 1V.  From their graphs that would be less than 1.5mA to 3.0mA depending on the device.  There's a few clipper circuits out there which would exceed that.

The fact a single nano-log device is equivalent to an anti-parallel *pair* of diodes means they are naturally balanced so I guess putting a cap in series with them is good insurance against DC.    You could get prolonged and unintentional DC if a circuit had a fault and the cap would prevent any long term DC.

[Vivek]

It does appear that a Si diode with a compliance resistor would give extremely similar transfer function as a Nano diode.

I would even proclaim that the slight differences will not be audible.

[amptramp]

It does appear that a Si diode with a compliance resistor would give extremely similar transfer function as a Nano diode.

I would even proclaim that the slight differences will not be audible.

But the mojo!  Think of the mojo of using a device made of eight molecules.  If guitarists shell out big bucks for bumblebee capacitors, think of what they would pay for nanolog diodes.  You could still make a profit off a nanolog Big Muff or Rat.

I am waiting for someone to debut a tube Big Muff or Rat using selenium rectifiers.  Lots of signal and lots of diode resistance.

[Fancy Lime]

It does appear that a Si diode with a compliance resistor would give extremely similar transfer function as a Nano diode.

I would even proclaim that the slight differences will not be audible.

But the mojo!  Think of the mojo of using a device made of eight molecules.  If guitarists shell out big bucks for bumblebee capacitors, think of what they would pay for nanolog diodes.  You could still make a profit off a nanolog Big Muff or Rat.

I am waiting for someone to debut a tube Big Muff or Rat using selenium rectifiers.  Lots of signal and lots of diode resistance.

New topic of this thread: Most complicated / impractical / expensive clipper that sounds exactly like a simple / common / cheap one.

[Steben]

low voltage zener diodes are almost the same, no? At least I like them.
Add a resistor to silicon clippers and cut half the volume and you have about a germanium response.
The same approach applies to most clippers.

[Vivek]

Patent 5124668

https://patents.justia.com/patent/5124668

https://patents.google.com/patent/US5124668A/en?oq=US5124668

[teemuk]

Ah, the old "Pocket Rockit".
There's a strikingly great deal in common and similarity to it's peers; "Rockman", "SansAmp", FMIC solid-state Fender amps, etc. Largely that there's not just a waveshaper to distort the signal but ALSO distinct pre and post distortion tone enhancement to concentrate IMD to narrower band of frequencies and to process the harmonics of output signal.

[iainpunk]

if you are in to interesting and weird clipping/waveshaping, here you go:

so i came across a thread about clipping and had the concept of 'dynamic crossover' i wasn't sure what was meant, but this is what i came up with.



it takes out the middle section of a wave independent of amplitude. crossover distortion without gating. does anyone think there is a use for this???

i won't be able to test this before tuesday so if anyone has a leftover breadboard and enough interest, please go ahead.

cheers, Iain

then i also have this:


its basically asymmetric wave folding, its kinda low gain but gets really distorted really quick but the clean does come through at the attack and the last decay

[Steben]

if you are in to interesting and weird clipping/waveshaping, here you go:

so i came across a thread about clipping and had the concept of 'dynamic crossover' i wasn't sure what was meant, but this is what i came up with.



it takes out the middle section of a wave independent of amplitude. crossover distortion without gating. does anyone think there is a use for this???

i won't be able to test this before tuesday so if anyone has a leftover breadboard and enough interest, please go ahead.

cheers, Iain

then i also have this:


its basically asymmetric wave folding, its kinda low gain but gets really distorted really quick but the clean does come through at the attack and the last decay

sound samples!