passive boost

[kdowqo]

when i was tinkering with my breadboard trying to figure out why transistors always seemed to work as they
should when someone else designed the circuit and never worked in my own I finally got something going on

this is what i got on my bread board right now and to my ears it boosts the sound + adds a very pleasant distortion


how can a circuit without any additional power boost my signal ?

[petemoore]

how can a circuit without any additional power boost my signal ?
  It can't.
  If every time the offcenter wheel spins, there's a 'bump' in the cycle [say the offcenter part hits something else, every cycle...you'd hear the hit as louder than the wheel spinning offcenter.
  Could be the clipping is putting a bump or 'spike' in the cycle, and this in turn puts a 'bump' in the speaker/air and your ''hearing equipment''.
  Although this takes a bit of power [so the average power would be reduced], during every cycle there's a power-spike which puts a 'bap' [so to speaker] in the signal, the 'bap' being much higher than the average potentail for an instant.

[Caferacernoc]

http://cavepassivepedals.com.au/glassy_mouth.html

They seem to do it passively with step up transformers.

[MikeH]

http://cavepassivepedals.com.au/glassy_mouth.html

They seem to do it passively with step up transformers.

I just checked out their demos, interesting but uh... their pedals don't sound very good at all to my ears.  I mean, it's cool that they're passive, but I would never use one.

[R.G.]

I sometimes think that the phrase "that's from a web page" will become synonymous with "that's a lie" or "that's deliberately misleading".

This is where that old stuff about having to understand some things so you don't get taken comes in. Let's recap:
First law of thermodynamics - Energy can neither be created nor destroyed. It can only change forms.
Second law of thermodynamics - energy systems have a tendency to increase their entropy rather than decrease it. The short form of that unwieldy statement is that energy flows from some concentrated energy source to a less concentrated place. So energy flows from some power source to places with less energy.

These have been paraphrased as (1) you can't win and (2) you can't even break even. If you run into a device which someone claims breaks either or both of these, you can assume (for the moment, until and unless we learn new physics that violates all of our present understandings) that they are either uninformed, mistaken, or lying. The second law is in fact the underlying cause why the patent office will no longer consider patents on perpetual motion machines, which violate that by definition.

With this bit of heavy hitting under our collective belts, let's consider.

how can a circuit without any additional power boost my signal ?

It can't, full stop. That would violate the Second Law. What it may be doing - and is, if I am reviewing the circuit correctly - is add some funny clipping. This adds harmonics which were not present, and psycoacoustically adds apparently loudness without adding any power. In fact, diode clippers always function by wasting energy above their clipping threshold. Something somewhere else must make up the loss if you want that amount of power back. Your ears are being fooled.

http://cavepassivepedals.com.au/glassy_mouth.html
They seem to do it passively with step up transformers.

Transformers are wonderful things. They are about as close to lossless energy conversion as we humans have ever gotten, bar that potential/kinetic thing. A good transformer will accept a certain amount of power on its input and give you upwards of 95-99% of that power back on the secondary. The remaining few percent (if the transformer is well designed!) are lost to powering up the core magnetic field, eddy current losses in the core, and Ohm's law losses in the winding wire. It's impossible, both in theory and practice so far, to make a transformer put out more power than you put in.

But how are those guys at cavepassivepedals doing this? Simple. They count on you providing the additional power to boost the signal back up once they've clipped it and done their various losses. They use transformers to step up the signal voltage (not a power question - power is volts times amps), from which they can clip and tone shape it, accepting the losses along the way, and they then give you a massaged voltage to power back up. I'm guessing their inspiration was microphone step up transformers.

"But-but-but-but-but-but-but-but-but-but-but-but-but- what's wrong with that?" I hear you saying. Not a thing. As long as you're willing to live with the compromises that this approach gives you. Transformers are not free, as you may have noticed, and **good** transformer are doubly not free. That has consequences.

A transformer gives you voltage gain. It does this by changing the turns ratio between primary and secondary. The available secondary current goes down in the same ratio as the voltage goes up. It has to - the power in the primary is Vin * Iin, and you can't get that much or more V*I out the secondary. You get less in fact, by that pesky Second Law. Guitar pickups are already in trouble for providing lots of current. That's why we have to have input impedances of over 1M typically. Any lower and you start losing treble.

When you toss a transformer into that mix in the middle, stepping up the secondary voltage, what you do is step DOWN the impedance the guitar sees at the primary. Let's say you get a voltage gain of 10 from your hypothetical transformer.  That's a voltage ratio of 1:10 from primary to secondary. The impedance that appears at the primary is the square of the turns ratio. So the primary impedance is 100 times less than the secondary impedance you load the transformer with. If we've been neglectful of our EE lessons and make that secondary impedance 1M without a second thought, then the primary of this 10:1 stepup transformer presents a 10K load to the guitar. Oops. Wait a minute - I'm pretty sure I had a magic tone-sucking-preventing amulet here somewhere. I'm going to need it. And we haven't even talked about the transformer's losses, nor any odd effects it has on tone, like bass response and treble response, midrange resonances, hum pickup, and so on.

Probably you can deal with these after a fashion, but after you get done with designing a really, really good transformer, by a really, really good and experienced transformer designer, and then pay for the fancy stuff you had to design in to get around the shortcomings of the transformer that you couldn't design away, a 9V battery and a transistor start looking pretty good.

Let's look at some of the front page from cavepassivepedals. Notice to anyone from cavepassive pedals: I'm not trying to pick on you, just pointing out what my personal understanding of engineering and physics tells me upon reading this. You're welcome and invited to tell me what I got wrong, and worse yet, provide backup information that will embarass me at my lack of understanding.

We have taken vintage technology and improved its capabilities.

That's a laudable goal. Not everything that's old is worthless or passe. For instance, cast iron really is a wonder material. It's just heavy, and that's mitigated against it in most modern applications.

When every electronics engineer focussed on creating smaller components, more efficient, portable power supplies and eventually, the digital revolution, the passive world took a massive step backward, plunging towards near extinction!

This is true mostly. I'm not sure that every EE focussed on smaller stuff, but the pressure to do smaller, faster, more efficient stuff has been pretty intense. I deplore the fact that modern EE graduates could not bias a three-transistor feedback ring if their life depended on it, and many of them really don't know which end of the soldering iron to hold onto. However, given the massively more demanding attitude we have today, near extinction may be the right place. I'd be very interested in seeing the design of a passive ipod, for instance.

If the human race had of realised that passive electronics had a long and exciting development ahead, that many things are possible without the use of a power source, would they still have given it up?

Yes. By the only good yardstick, they did. Most of the human race has no clue what active and passive electronics are, or how they differ. And having a long and exciting development ahead does not relieve the limitations of passive electronics. Passive electronics have their limitations, starting with the first and second laws. Many things are possible without external power, but not as many as this statement alludes to. No matter how long and exciting the road is, if it doesn't go where you want to go, it's not much help. I think again about the passive ipod design.

"Crystal sets" have long been forgotten. To receive radio transmissions without the need for 240 volts or a pack of 1.5 volt batteries would blow most people's minds of today.

They are neat. I discovered crystal sets at about age 10, back when water animals were first crawling out on shore. However, after the novelty of hearing anything come out of the earphone, they'd quickly get tired of looking for a place to clip to a big antenna, and complain that they could not take it with them. Receiving radio without batteries is neat, OK. But not if you can't power a speaker with it, or if it's not portable if you have to use earphones. Or if the frequency response isn't all that great. The mind blow interval would be terrifyingly short. They'd be bored with it in a second once they saw it and understood its limitations. It's a novelty. "Cool! Look at that. What's next?"

Even more bizarre would be the concept of "wireless transmission of free energy" that Nikola Tesla was prevented from giving to the world! Imagine, never having to worry about finding a wall socket or changing flat batteries.

That is neat stuff. But there are gotchas in there. Remember the folks who say their kids got leukemia because they live within half a mile of power transmission lines? And the folks who are convinced that you'll get brain cancer if you hold your cell phone up to your ear? How many people would like to convert over to Tesla-style power transmission.

And then there's that. It is **transmission** and not "free energy". For this to work, somebody somewhere is burning fuel, catching sunlight, splitting atoms, or fusing atoms to make the energy. It's being broadcast like radio - which it is - and the transmitted power is intense enough to be caught and used. And there are certain issues with living in intense radio fields. For one, microwave ovens are intense radio fields. True, they have a very specialized frequency, but you get the idea. Anything that can accidentally catch the pervasive field gets hot. Like - oh, shoot! - fences maybe.  A fence looks very much like a good receptor for Tesla-transmitted energy. Want every fence to be an electric one? Or your neighbor's fence keeping your garbage disposal and/or TV from running because it shades you from the field?

And back to the Second Law. There's a pot full of energy being transmitted. Where does the excess we don't use go? Yep, you got it - it radiates away somewhere. How much of it could we use if we did this? Remember we don't have any perfect collectors/antennae. I think that the folks burning coal/gas/oil/atoms back at the power station have to produce the peak power demand all the time in case someone needs it, and let the excess radiate away, there being no good way to catch it and recycle it. Oh, wait! We could lay out large grids of wires and catch it, then use big heavy wires to lead it back to the power plant to be recycled!!
Oh, wait... 

Where ever you went, your radio could keep playing...indefinitely! All this is possible with vintage technology!

Yep. As they used to say to me "How much would you pay to get that scenario?" 

We have taken a step back in time to bring you, the musician, what should have been.

Should have been? I think that's a very debatable point, on both the uneducated musical consumer's desires and on technical grounds. 

We are the first to re-establish passive electronics in a world that refuses to believe that nothing can be achieved without a power supply.

I applaud you for your attempt, and wish you luck with the technical issues. Frankly, I think the technical issues are much simpler to deal with than the somewhat intractable issues with customer satisfaction. But what do I know? If I were a marketing wizard, I'd already be rich.

I wish you luck with your passive approach to musical technology.

[petemoore]

  It can't amplify doesn't necessariy translate to it isn't cool.
  I've had circuits that didn't work, and I remember them sounding plenty cool, once in a while, I don't know what it was before the fix with that one FF I got working that made it sound so cool.

[R.G.]

  It can't amplify doesn't necessariy translate to it isn't cool.
  I've had circuits that didn't work, and I remember them sounding plenty cool, once in a while, I don't know what it was before the fix with that one FF I got working that made it sound so cool.

You're absolutely right - coolness does not equate with active amplification.

[Nasse]

I am sure I saw an ad for passive gadget which they claim was boost but had tubey sound too, some kind of

[solderman]

Thanks' R.G.
That long and well written post sent me back a good 30 years to the classroom we had for conducting physic's labs when I went to, what's equivalent to collage where I live. I can almost smell burnt paper and enamel coat on the copper wire melting in the transformers when we "mistakenly" shortened them. We also had magnets that we demagnetized or re magnetized with reversed polarity. Besides that our teacher also managed to blow the main fuse in the physics building when he showed us how to re wire the 3 phase AC to 3x 1-phase (or something like that) in our High voltage lab. No wonder I didn't become a teacher, poor sods.

In that same building we also had a Rolls Royse  Merlin MK III engine. To take off and tamper with the heads and valves on that one was part of the mechanic's class.  The best part was to start I up. The sound is something else. That sound beats all the destorted stomp boxes in the world. This is a mean V12 sucker with about 1500 hp.
It was one of the most common airplane engines in the 2:nd WW and sat in classic fighter planes like the Spitfire, Hawker Hurricane, DeHavilland Mosquito, P52- Mustang, and the Lancaster bomber.

http://www.aviation-history.com/engines/merlinv1650-1a.jpg

Opps nostalgia took me too far back

[Brymus]

Uh oh,Jay Lenno is looking for Merlin engines to build a new super bike now.JK
Sounds cool solderman,I would love to work on an engine like that.

[R.G.]

I am sure I saw an ad for passive gadget which they claim was boost but had tubey sound too, some kind of

I have no doubt that someone did do that.

There's the real world, where Mother Nature's Rules apply, and there's the world of advertising, where anything the sucker... er,  customer will pay for is possible. 

[kdowqo]

the schematic I posted has nothing to do with cavepassivepedals.com it was just what I ended up with on my breadboard after some failures trying to understand how transistors work

however it turned out that the reason that it did boost the sound seams to be that I played it through my popstarz karaoke-machine which I use as echo (its the best I've got)
the karaoke-machine seems to mess with the pedals + the guitar connected to it thus causing the effect before it to act like a boost
the volume-control on the guitar also crackles when the guitar is connected to the karaoke-machine

when the popstarz was out of the way the "passive boost" actually lowered the volume   

[MikeH]

I sometimes think that the phrase "that's from a web page" will become synonymous with "that's a lie" or "that's deliberately misleading".

This is where that old stuff about having to understand some things so you don't get taken comes in. Let's recap:
First law of thermodynamics - Energy can neither be created nor destroyed. It can only change forms.
Second law of thermodynamics - energy systems have a tendency to increase their entropy rather than decrease it. The short form of that unwieldy statement is that energy flows from some concentrated energy source to a less concentrated place. So energy flows from some power source to places with less energy.

These have been paraphrased as (1) you can't win and (2) you can't even break even. If you run into a device which someone claims breaks either or both of these, you can assume (for the moment, until and unless we learn new physics that violates all of our present understandings) that they are either uninformed, mistaken, or lying. The second law is in fact the underlying cause why the patent office will no longer consider patents on perpetual motion machines, which violate that by definition.

With this bit of heavy hitting under our collective belts, let's consider.

how can a circuit without any additional power boost my signal ?

It can't, full stop. That would violate the Second Law. What it may be doing - and is, if I am reviewing the circuit correctly - is add some funny clipping. This adds harmonics which were not present, and psycoacoustically adds apparently loudness without adding any power. In fact, diode clippers always function by wasting energy above their clipping threshold. Something somewhere else must make up the loss if you want that amount of power back. Your ears are being fooled.

Oh man, this thread is giving me deja vu:

http://www.diystompboxes.com/smfforum/index.php?topic=60256.0

[earthtonesaudio]

I think we need more "passive activists."

There are several ways you can power your pedals with "free" energy, such as a wah-wah with a generator hooked up to the rocker, or pressure-sensitive piezoelectric stompswitches, or even powering your effects with the guitar's AC signal itself.  And of course solar power in all its forms.
By "free" energy, I of course mean energy sources that you were already simply wasting, that could instead be harnessed and put to useful work.

Or how about this:
A mute pedal which routes your guitar's signal through a rectifier and uses it to charge up some capacitance or battery.  Mute, strum vigorously, then unmute and the energy you just put in goes to your various (micro-power) pedals.

[wavley]

Ahh, reminds me of my solar powered pedalboard days, back when our band's rider required 12 Par64 cans pointed stage left.

[MikeH]

Deja vu indeed...

The essence of engineering economics is the equivalence of money and energy. For instance, a US dollar is most easily defined at the moment as being worth a bit more than 1% of the energy in a barrel of oil. Let's assume that the MEG mentioned in the web site you reference exists and works as shown. It's of simple construction; I could build one and test it, and so could many other people, easily. So therefore if it works as stated, I could make a device that would produce an excess of energy, in the form of electricity. So I could, personally, set up a device that would reduce my electric bill every month. I could use that money to build another unit, and reduce my bill further. Eventually I pay nothing for electricity because it is coming out of my MEGs free.

If I am disciplined, I continue to use my monthly "electric bill" money to build more MEGs. Now I produce an excess of electricity. In Austin, the electrical utility must, by law BUY my self produced electricity if I set up the feeds to the power line correctly. And I can, because I have a source of free electricity and cash that I'm not paying. At some point, I have invested enough of my monthly electricity bill to gain a monthly payment back from the power company. When that happens, I have a positive cash flow from selling my excess electricity, and I get free money.  I invest the returns in more and bigger MEGs. Soon, the power company approaches the legislature and demands to not have to pay me because they're going broke. The legislature rescinds the "must buy" law for them. But I can now (a) sell big MEG setups to my neighbors (b) sell the excess power to my friends (c) use the excess power to manufacture things with the free electricity, turning it into money again. I can in particular manufacture big MEG setups to sell to anyone who wants to be free of electrical bills.

I can use my free electricity to convert water to oxygen and hydrogen and power machinery with. So my gasoline bill vanishes. Even simpler, I use the excess money to buy gasoline so the gasoline bill effectively vanishes. Money equals energy again.

You see what happens. If the MEG works, we would now be witnessing the dismantling of the power companies and oil companies. It's been long enough since the patenting of the MEG. Even if the government/big business/etc. tried they could not suppress it because once the principle is known and spread to the net, people can independently go make their own. Think of the vast business enterprise that has arisen around the trade in drugs, which is being vigorously and violently suppressed. The governments can't stop it. In the same way, governments are powerless to suppress something so fundamental as free energy, which equals free money. Especially where the ability exists to start with such a simple device as shown in the MEG patent. If there was a huge investment to be made, millions if not billions of dollars to create even the first kW-Hr of electricity, they maybe it could be suppressed. But the MEG as shown can be made by a guy who's sitting in his garage back in the hills in Idaho and wants to live off-grid anyway. There are a lot of those people in the USA, enough that a real free-electricity device that worked would instantly be picked up and used. They use solar cells to do the same now.

Even if such a device existed, and could be restricted to the energy companies, it would instantly kill the global trade in oil. No reason to cooperate with those dirty guys wherever else if I can make my own energy here. If I'm an oil company I can use the free electricity to SYNTHESIZE oil. To say that the ongoing oil trade is a sham is to imply that the entire fiscal and legal energy of governments and business is increasingly invested in a sham to hide a free energy source. The sham must collapse, or eventually the entire business world is doing nothing but participating in a scheme to hide the free energy.

That there is no sign of such a collapse is an indication that the MEG (or some alternate, but equivalent result device) does not yet exist. Occam's Razor tells us that of the two possibilities, (i.e. free energy existing but being hidden and suppressed, versus not yet existing) the simpler explanation must be the most likely one.

[PRR]

>> "realised that passive electronics had a long and exciting development ahead"
> ... ... Passive electronics have their limitations,... ... ...

Passive audio's path is clear.

Many attempts to build a telephone. All early true passive telephones turned a shout into a faint whisper. The more promising telephone schemes took power. One common thread was a rotating (hand-crank) drum with a friction shoe: the friction was modulated by speech current and the mechanical energy out could exceed the electric speech energy in.

(Let's ignore static electromagnets because in principle they may be replaced by permanent magnets.)

Bell's malfunctioning Harmonic Telegraph, patent 174,465, the root of the telephone business, clearly shows a battery. The amplification may have been variable-depth immersion in an electrolyte. Bell probably didn't know what was going on.

The key to wide use of telephone technology is the carbon microphone, which is quite clearly an amplifier, somewhat like an FET except the "gate" is a pressure-point which may be jiggled by a diaphragm.

From 1877 to past 1907, pretty much all audio worked this way. Not passive (the carbon-button amplifier was battery-powered), but not "electronics" (vacuum tubes with their loose electrons). Most of the foundations of electronics were laid: wave-filters, impedances, transformers, clipping, horns. This WAS "a long and exciting development".

Much of this became trailing-edge when tubes became readily available around 1920. Tubes could do more things.

For completeness: true passive telephones did happen. The idea is shown in the Second Bell Patent, 1877, but was not workable at the time. Highly tuned resonant transducers were developed (perhaps with the aid of tube test gear) which could get around 50% efficiency. Two of these on short wire can put 25% of a shout into an ear. These were useful on battlefields and farms where batteries were not readily available. After WWII surplus sound-powered field telephone sets became standard tools for aiming the newfangled TV antennas on roofs (no, the guy on the roof could not call the guy at the TV on his cellphone).

Getting to guitar: well, go back to a dynamic (passive!) mike into a tube grid. The number of turns on the moving coil must be limited: mass must be teeny and wire can not be made infinitely thin. We use a 1:10 transformer to couple to the high impedance grid. You can wind a guitar pickup with a few hundred turns and then transformer it to the grid: early Les Paul Recording guitars did. However there's no urgent need to keep a pickup winding's mass low: it does not move. So instead of a few hundred turns to a 1:10 transformer, you wind 10 times as many turns on the pickup, and have "built-in transformation".

Crystal radios can have great fidelity. If they are loud enough to hear. My problem was I was 1 mile from a 50KW tower. Anything would pick that up. Loud! No reasonable simple (1-tank) rig would pick up ANYthing else.

[R.G.]

I think we need more "passive activists."

There are several ways you can power your pedals with "free" energy, such as a wah-wah with a generator hooked up to the rocker, or pressure-sensitive piezoelectric stompswitches, or even powering your effects with the guitar's AC signal itself.  And of course solar power in all its forms.
By "free" energy, I of course mean energy sources that you were already simply wasting, that could instead be harnessed and put to useful work.

Or how about this:
A mute pedal which routes your guitar's signal through a rectifier and uses it to charge up some capacitance or battery.  Mute, strum vigorously, then unmute and the energy you just put in goes to your various (micro-power) pedals.

That's a really good idea. How about the band members, instead of prancing about on stage, sit on stationary-bicycle generators and their vigorous pedaling powers their pedals and amps! 

Even better, all seats in the auditorium are replaced with stationary bicycle generator sets and the audience must pedal to hear the group perform. I suspect that the audience produces more waste energy than the band. And let's not even talk about what energy it took to get the audience there to hear the group play. Make the audience stay home and only hear it broadcast to them in heavily compressed MP3, to save both the transportation cost to the venue, and the bandwidth to transmit full-bandwidth audio. Perhaps even better, we could just mail the audience a paper copy of the review of the one person who was delegated to listen to the band for everyone else, and who listened to the band's individual MP3s for each instrumental and vocal part, transmitted to the reviewer without the band ever going to the venue, or even meeting face to face. 

If we play it right, we can set things up so that no one can... er, has to travel anywhere to hear music or anything else. That'll be much more energy efficient. Not very pleasing or enjoyable, but it won't waste any energy.

[solderman]

I'm getting confused here
Are we talking about how to power our pedals, power pedals or pedal power. In that case this guy has it going for him. This proves that this issue is as old as the electrons them self. And he has taken it even further. He is powering he's amp as well.



Any way, I agree wirt R.G. It's time that we in the DIY scene took the global warming more seriously. I suggest that we introduce the carbon monoxide neutral guitar rig. Here my idée.
At live concerts triple the amount of speakers (at least).  Use 2/3 of the speakers to absorb the energy made by the howling crowd of fans doing their normal audience behavior and screaming there buts of . Transform that energy to the bands equipment and you have an environmentally safe concert.
This will also be sort of a Darvinistic way of sorting the magnificent bands that will have a roaring audience and the ones (the type I've played in) with no audience.  No scream, no noise, no play.
Instead of recording the band could play in to a plastic bag and sell it.

[FiveseveN]

this issue is as old as the electrons

13.7 billion years old?!
You do have a point about the crowd being a potential energy source, though. Makes me think of last night's mosh pit in a whole new way