Wah Inductor in a distortion/overdrive pedal?

[johngreene]

Oh, but hasn't been done in a commerically sold Distortion pedal, gotcha.

Take a closer look Chris.

?
I would venture to say the pictures you posted are not a commercially sold distortion pedal. Did I miss something?

--john

[Harry Palms]

It's definitely been done before.

http://www.musiciansfriend.com/product/Danelectro-DJ10-Grilled-Cheese-Distortion-Pedal?sku=151869

It's got a lot of potential.

Then again, maybe not.

http://www.soundclick.com/bands/pagemusic.cfm?bandID=156883

Under "GC Splatter"

[johngreene]

It's definitely been done before.

http://www.musiciansfriend.com/product/Danelectro-DJ10-Grilled-Cheese-Distortion-Pedal?sku=151869

It's got a lot of potential.

Then again, maybe not.

http://www.soundclick.com/bands/pagemusic.cfm?bandID=156883

Under "GC Splatter"

So, I guess you are saying in a very cryptic way that the grilled cheese has an inductor in the pedal (which doesn't have an 'EQ', just a resonance control) and that the sound clip was some kind of modificaton that involved an octave circuit using a transformer from radio shack that 'splattered'?

I don't understand why you can't just say what it is you are trying to imply?

--john

[R.G.]

At the risk of raining on a number of parades, I feel obligated to note that there is nothing special that simply having an inductor present can do to tone that cannot be done with active devices, resistors and capacitors.

Inductors are nothing more than quadrature-shifted capacitors. There is no magic hidden in there, just like having a germanium transistor in your pedal does not make it automatically sound better.

A fair majority of the field of active filters stems from the search for ways to do without inductors; not because the inductors are magic and rare, with unobtainable results. Instead because inductors are heavy, expensive, poorly predictable, large, and ungainly solutions in most cases.

You can get any frequency-response-related results for an inductor by other means.

Inductors in power supplies are another story.

[petemoore]

  What could be easier to change the response of a circuit than throwing an inductor in there?
  Taking it right back out because now this circuit sometimes acts horrible to funny with itself or with other pedals.

[johngreene]

At the risk of raining on a number of parades, I feel obligated to note that there is nothing special that simply having an inductor present can do to tone that cannot be done with active devices, resistors and capacitors.

But did you not do a whole analysis on your website about the 'magic' wha inductor?

Inductors are nothing more than quadrature-shifted capacitors. There is no magic hidden in there, just like having a germanium transistor in your pedal does not make it automatically sound better.

unless they are the magic inductors?

A fair majority of the field of active filters stems from the search for ways to do without inductors; not because the inductors are magic and rare, with unobtainable results. Instead because inductors are heavy, expensive, poorly predictable, large, and ungainly solutions in most cases.

You can get any frequency-response-related results for an inductor by other means.

This seems to be entirely contradictory to your wah inductor analysis. what's up?

Quote from your webpage:

I was entrusted with one of the magic versions by a friend, and spent some time in an EE lab with this wah and a garden variety Crybaby. I took both inductors out and measured their inductance, resistance, self-capacitance, and came to no good conclusions on why there should be any difference in the sound. It wasn't until I put a sine wave generator through the inductor and looked at the current through the inductor on a spectrum analyzer that the differences showed up.

Now you are saying they don't have any 'special' qualities?

--john

[Harry Palms]

John, sorry.  I didn't even think about being cryptic. I've found that if I restrict myself to posts of only one or two lines I suffer far less from foot in mouth disease. That's all. I've spent so much time with that whole dano series of plastic junk that maybe I just assume others will recognize them as readily as I do. I go to sleep at night sometimes seeing those colorful boxes swirling before my closed eyes. They taunt me - "Come on, open us up and look inside. You know you want to. Get up. Do it." 

I'm afraid now of the DODs. Those little demons seem to be beginning to demand equal time.

[amz-fx]

Here's a way to use the inductor that I've fooled around with before...  it is just a TS-9 tone control with an added inductor.  You have to tweek the RLC values to get it to do what you want.



This is basically the same idea used in the just about every "metal" pedal produced by Boss, Ibanez, DOD, etc.  except the gyrator (synthetic inductor) has been replaced by a real inductor.

There are a number of other ways to use a wah inductor in a pedal as well...

regards, Jack

[R.G.]

But did you not do a whole analysis on your website about the 'magic' wha inductor?

I did. The point of that article was to show that the "magic" was explainable by knowing more about the specific inductor, not that it was inexplainably great. I have this dislike for inexplainably great things. I want to know **why**.

Quote from: R.G. on Today at 01:01:05 AM

Inductors are nothing more than quadrature-shifted capacitors. There is no magic hidden in there, just like having a germanium transistor in your pedal does not make it automatically sound better.

unless they are the magic inductors?

Unless they are inductors with a reputation for being "magic" that is based on an unusual imperfection showing up.

This seems to be entirely contradictory to your wah inductor analysis. what's up?

It's entirely consistent. Take an inductor in the Vox wah circuit. Use the remanence of the core material to make it saturate asymmetrically. Now you have a "magic" inductor. Take a gyrator. Clip the signal out of the inductor in a soft, asymmetrical fashion. Now you have a "magic" gyrator. The point is that there is nothing that is unique to the part being an inductor that cannot be done by other means. An inductor may be the simplest way conceptually to do it, being just a coil of wire on a core with two leads, but the complex way of doing it, with active devices and RCs can do the same thing, and is probably smaller and cheaper to build.

Now you are saying they don't have any 'special' qualities?

Nope, that's not what I'm saying. The original post that started this thread expressed a degree of wonder about using inductors in stompboxes.

I'm saying that the concept that the use of an inductor is somehow special in some way is a simplistic view, not well founded in theory. Just because there is an inductor there does not mean that there is a tone or response that is not otherwise available.

You know this stuff John. Inductors are not magic just because they're inductors. They're just another part that you have to learn both the perfect version of and the common imperfections to apply well. And there are multiple ways to both use them and work around using them.

Here's a way to use the inductor that I've fooled around with before...  it is just a TS-9 tone control with an added inductor.  You have to tweek the RLC values to get it to do what you want... the gyrator (synthetic inductor) has been replaced by a real inductor.

That's kind of my point. One can use an inductor or a gyrator in the circuit interchangeably. The transistor, two caps and three resistors in the gyrator is usually cheaper and smaller than the real inductor, which is why it's used.

[Jay Doyle]

http://www.diystompboxes.com/pedals/schems/TimbreBox.pdf

This is the TS tone control, with a discrete opamp instead of an IC, three bands instead of one, and an added inductor in the form of a gyrator.

This is Jack's example above with gyrators replicating real inductors.

This is old and I haven't updated it in a while, but even though I say that I haven't found the formulas in the document, they are in R.G.'s excellent write up on EQs:

http://www.geofex.com/Article_Folders/EQs/paramet.htm

Hope this all helps,

Jay Doyle

[johngreene]

You know this stuff John. Inductors are not magic just because they're inductors. They're just another part that you have to learn both the perfect version of and the common imperfections to apply well. And there are multiple ways to both use them and work around using them.

Yes, I do. And it is a large part of why I responded. You stated that inductors are nothing more than quadrature-shifted capacitors which is only true in the 'ideal' world. In reality they are no where close so I decided to call you on such a generalization. From the standpoint of Q alone, inductors cannot be considered as simple as a quadrature-shifted capacitor. Otherwise everything would work as perfectly as pspice tells us it should.

So if you re-read my response using the 'quadrature-shifted capacitor' as a reference point, you should be able to see my point. I saw it as you contradicting yourself. I meant it to be less 'pointed' than it was and I apologize for that. It sounded much different in my head than it reads.

--john

[johngreene]

John, sorry.  I didn't even think about being cryptic. I've found that if I restrict myself to posts of only one or two lines I suffer far less from foot in mouth disease. That's all. I've spent so much time with that whole dano series of plastic junk that maybe I just assume others will recognize them as readily as I do. I go to sleep at night sometimes seeing those colorful boxes swirling before my closed eyes. They taunt me - "Come on, open us up and look inside. You know you want to. Get up. Do it." 

I'm afraid now of the DODs. Those little demons seem to be beginning to demand equal time.

Well you sucked me in. I went and ordered one just to see it for myself!

--john

[Chris Frailin]

John, sorry.  I didn't even think about being cryptic. I've found that if I restrict myself to posts of only one or two lines I suffer far less from foot in mouth disease. That's all. I've spent so much time with that whole dano series of plastic junk that maybe I just assume others will recognize them as readily as I do. I go to sleep at night sometimes seeing those colorful boxes swirling before my closed eyes. They taunt me - "Come on, open us up and look inside. You know you want to. Get up. Do it." 

I'm afraid now of the DODs. Those little demons seem to be beginning to demand equal time.

Well you sucked me in. I went and ordered one just to see it for myself!

--john

diggin' the helmet Mr Greene;)

[johngreene]

keeps the aliens from scanning my brain.

[johngreene]

At the risk of raining on a number of parades, I feel obligated to note that there is nothing special that simply having an inductor present can do to tone that cannot be done with active devices, resistors and capacitors.

Inductors are nothing more than quadrature-shifted capacitors. There is no magic hidden in there, just like having a germanium transistor in your pedal does not make it automatically sound better.

A fair majority of the field of active filters stems from the search for ways to do without inductors; not because the inductors are magic and rare, with unobtainable results. Instead because inductors are heavy, expensive, poorly predictable, large, and ungainly solutions in most cases.

You can get any frequency-response-related results for an inductor by other means.

Inductors in power supplies are another story.

At the risk of bringing the original thread back on topic......

Didn't this discussion start with the claim of using a 'wah' inductor in an EQ circuit? I see this as an intentional use of the unique qualities of a 'magic' inductor. Not just an 'inductor' in the general sense.

--john

[Ben N]

This is an interesting thread--surely, any discussion involving RG Keen, John Greene, Jack Orman and Jay Doyle is going to have something to offer.  But I have one doltish question:
What the devil is a "quadrature shifted capacitor"   ?

Ben

[johngreene]

This is an interesting thread--surely, any discussion involving RG Keen, John Greene, Jack Orman and Jay Doyle is going to have something to offer.  But I have one doltish question:
What the devil is a "quadrature shifted capacitor"   ?

Ben

In the electronics world, Quadrature refers to phase. If you take your standard cartesian coordinate system, a vector that is shifted 90 degrees from another is considered to be 'in quadrature'. i.e. shifted by 90 degrees. An inductor is actually shifted 180 degrees from a capacitor so calling it a 'quadrature-shifted capacitor' is not entirely accruate. But I knew what he meant.

Wait until we start talking about 'orthogonal'.

--john

[Ben N]

Hey!  If you were my kid I'd wash your mouth out with soap!



From the Adventures of Huckleberry Finn (Please excuse the language of the time--just seems kind of apropos here):

    "Why, Huck, doan' de French people talk de same way we does?"

     "No, Jim; you couldn't understand a word they said -- not a single word."

     "Well, now, I be ding-busted! How do dat come?"

     "I don't know; but it's so. I got some of their jabber out of a book. S'pose a man was to come to you and say Polly-voo-franzy -- what would you think?"

      "I wouldn' think nuff'n; I'd take en bust him over de head -- dat is, if he warn't white. I wouldn't 'low no nigger to call me dat."

     "Shucks, it ain't calling you anything. It's only saying, do you know how to talk French?"

     "Well, den, why couldn't he say it?"

     "Why, he is a-saying it. That's a Frenchman's way of saying it."

     "Well, it's a blame ridicklous way, en I doan' want to hear no mo' 'bout it. Dey ain' no sense in it."

     "Looky here, Jim; does a cat talk like we do?"

     "No, a cat don't."

     "Well, does a cow?"

     "No, a cow don't, nuther."

     "Does a cat talk like a cow, or a cow talk like a cat?"

     "No, dey don't."

     "It's natural and right for 'em to talk different from each other, ain't it?"

     "Course."

     "And ain't it natural and right for a cat and a cow to talk different from us?"

     "Why, mos' sholy it is."

     "Well, then, why ain't it natural and right for a Frenchman to talk different from us? You answer me that."

     "Is a cat a man, Huck?"

     "No."

     "Well, den, dey ain't no sense in a cat talkin' like a man. Is a cow a man? -- er is a cow a cat?"

     "No, she ain't either of them."

     "Well, den, she ain't got no business to talk like either one er the yuther of 'em. Is a Frenchman a man?"

     "Yes."

     "WELL, den! Dad blame it, why doan' he talk like a man? You answer me dat!"


Anyway, John, thanks for the explanation.

[Jay Doyle]

At the risk of bringing the original thread back on topic......

Didn't this discussion start with the claim of using a 'wah' inductor in an EQ circuit? I see this as an intentional use of the unique qualities of a 'magic' inductor. Not just an 'inductor' in the general sense.

--john

Good point John. Please understand that I'm not saying that your approach or ideas are wrong.

Mine point (and R.G.'s, I think, if I can speak for him) is only that it may be possible to acheive the same 'magic' qualities you want and are looking for by 'optimizing' a gyrator configuration to match that 'magic' you are looking for without having to rely on a part to be 'right'. If we could figure out which parts of, say, a BJT buffered gyrator (I think that when you start going IC opamp buffered, you are going to be getting too close to ideal and you won't have as many variables to adjust), effect which qualities we are/are not looking for, we could get what we wanted, probably a lot more reproducable, and with two caps, three resistors and a BJT. No hunks of iron that you have to sort through to find a 'right' one.

I personally think (and am as responsible) that the gyrator is one of the most underexplored avenues in our little FX world. I need to look into it some more.

Jay Doyle

[johngreene]

At the risk of bringing the original thread back on topic......

Didn't this discussion start with the claim of using a 'wah' inductor in an EQ circuit? I see this as an intentional use of the unique qualities of a 'magic' inductor. Not just an 'inductor' in the general sense.

--john

Good point John. Please understand that I'm not saying that your approach or ideas are wrong.

Mine point (and R.G.'s, I think, if I can speak for him) is only that it may be possible to acheive the same 'magic' qualities you want and are looking for by 'optimizing' a gyrator configuration to match that 'magic' you are looking for without having to rely on a part to be 'right'. If we could figure out which parts of, say, a BJT buffered gyrator (I think that when you start going IC opamp buffered, you are going to be getting too close to ideal and you won't have as many variables to adjust), effect which qualities we are/are not looking for, we could get what we wanted, probably a lot more reproducable, and with two caps, three resistors and a BJT. No hunks of iron that you have to sort through to find a 'right' one.

I personally think (and am as responsible) that the gyrator is one of the most underexplored avenues in our little FX world. I need to look into it some more.

Jay Doyle

Don't worry Jay, I'm good.

I have actually done a lot of experimenting with gyrators in pedals. (10+ years ago?, dang time flies). My wah didn't work very well at all. One of the biggest problems is dynamic range. So they work best where there is very little signal swing. Like the inverting input of a non-inverting amplifier. Passive inductors at audio frequencies are very problematic. Q, size, etc are all more of a challenge.

--john