John Curl's Blowtorch preamplifier

[Andre Visser]

There's a difference between a current and a field. Now, there does need to be a potential difference for the current to flow, but that's at the ends of the conductor.

Something that puzzles me, which is first, the current or the field?

Or it could mean that I'm trying to give a general picture to a guy who's curious but has zero background in physics or material science. 😉

Thanks again.

 

[john curl]

Badmouthing me is equally bad! Just because YOU don't believe in audio subtlety, doesn't say very much at all. Any more, than I know the differences between fine wines or French cooking. I, at least, respect it when I engage it, rather badmouth the cost of a good lunch or a bottle of fine wine.

 

[SY]

Calling Ernst Mach!

If you think about it, a wire with excellent conductivity won't have a potential difference between its ends, even with current running through it, right? Now, indeed, that's slightly oversimplified and there are certainly voltage drops through a wire, but to first order, you can consider the drop zero.

Here's a useful way to visualize it: if I want to shoot a golf ball through a hose, it takes a lot of initial velocity and there's a time lag between the ball going in one end and out the other. But if the hose is full of golf balls and they are absolutely indistinguishable, I can with very little effort push the golf ball into one end and have it (or its perfect replica) pop out the other end with almost no force and almost no time delay. You have an array of golf balls when you start and an identical array when you're done.

Now, in the case of a metallic conductor, the golf balls are the electronic charge cloud of the conduction band electrons. There's a periodic potential (think of it as circumferential ridges in the hose) from the nuclei/core electrons, but they can be thought of as pretty much fixed in place- after all, a copper nucleus is about 110,000 times an electron mass... When excited by an AC signal, golf balls are popping in one end, then out the other, then the process reverses. The golf balls in the hose don't move much.

Again, this is a VERY simplified model, but the take aways are:

1. A conductor by definition is something that allows lots of current to flow with negligible potential difference.
2. The big, heavy nuclei of a conductive metal can be thought of as being fixed in position (not strictly true, but hifi signals are rather well below phonon frequencies).
3. Dielectrics work by the "sloshing" back and forth of electron density as a field is applied to the material.

 

[dimitri]

Stuart, Berkeley Pit was closed for awhile, searching for gold in Butte, MT?

 

[scott wurcer]

Just because YOU don't believe in audio subtlety, doesn't say very much at all.

The point lately is that even the proponents don't think this stuff is subtle. Speaking of wine, I had a good laugh at Graham Ramsey giving Jamie Oliver's sommelier a bottle of Chateau Petrus ($2000) blind, they were both as clueless as could be. The exchange about it being or not being "corked" would amuse SY.

 

[john curl]

This is sort of the DRUDE theory, about 100 years old, SY. More is known, today.
Ernst Mach once said:"I can accept the theory of relativity, as little as I can accept the existence of atoms and other such dogmas." 1913
I have one of Ernst Mach's textbooks. Want to read up, SY?

 

[SY]

John, "pedagogy" is a word worth looking up.

 

[scott wurcer]

Ernst Mach once said:"I can accept the theory of relativity, as little as I can accept the existence of atoms and other such dogmas." 1913

As late as the 50's people seriously thought something incredible would happen if one broke the sound barrier.

 

[Wavebourn]

Re: Re: Iron, Fe, magnetic metal

opportunity
improved tubes

I use such tubes in my amps. GU-50 output pentodes, with nickel anodes.

 

[john curl]

SY V(F) is more than 10 times V(0)[Drude calculation) therefore you are not as accurate, and this concerns me.

 

[john curl]

Many here don't understand the difference between nickel and frying pan iron. Too bad. Both are magnetic, one is a necessity, the other, a cost saving substitution.

 

[john curl]

SY, I am not trying to teach 'them'. I am trying to teach you and Scott.
I realize that you might be trying to teach 'them', but you must be accurate, or else everyone falls into your point of view.

 

[Wavebourn]

Many here don't understand the difference between nickel and frying pan iron. Too bad. Both are magnetic, one is a necessity, the other, a cost saving substitution.

I am totally ignorant in frying pans, but nickel anodes allow much wider range of temperatures than made of a steel.

 

[syn08]

Assumed a conductor is placed into an stationary (not time variable) e-field, then only for a _very_ short moment an inner e-field exists until the electrons are moved;

That is of the order of magnitude of the relaxation time. A time constant of about a few picoseconds at best.

Now, waiting for somebody to jump in and tell us how important those picoseconds are for the microdynamics of music.

 

[syn08]

I realize that you might be trying to teach 'them', but you must be accurate, or else everyone falls into your point of view.

No ****, Jose? What about yourself and your "teachings"?

 

[gallon]

Re: Calling Ernst Mach!

Here's a useful way to visualize it: if I want to shoot a golf ball through a hose, it takes a lot of initial velocity and there's a time lag between the ball going in one end and out the other. But if the hose is full of golf balls and they are absolutely indistinguishable, I can with very little effort push the golf ball into one end and have it (or its perfect replica) pop out the other end with almost no force and almost no time delay. You have an array of golf balls when you start and an identical array when you're done.

A useful image here that everyone has seen is that little desktop toy with the row of suspended bearing balls. Pick up one ball and let it swing down, and when it contacts an identical ball flies off the opposite end.

Hmmm. Are we saying that electrons are incompressible objects?

🙂

 

[Philip the GH]

I would recommend starting from physics and experimenting, experimenting, experimenting....

Agreed, the building blocks are not that difficult. I'd suggest not reading Mr. Self and learning to draw your own conclusions.

Reinventing the wheel and again and again and again?

No, learning the fundamentals for ones self.

 

[FrankWW]

Wavebourne,

The point of the reference I posted, which is a good piece of research by a respectable scientist, is that our sensitivity to linear distortion increases in a non-linear fashion as SPL increases, not, as you write,

Since audio sensitivity is logarithmic, on higher SPLs so called linear distortions should be less audible

Here is the reference again

http://www.gedlee.com/downloads/AES06Gedlee_ll.pdf

Audibility of Linear Distortion
with Variations in Sound Pressure Level
and Group Delay



Now, SYN08 wrote

http://www.diyaudio.com/forums/showthread.php?postid=1811008#post1811008

Yes. According to the definition of "linear distortion" a filter is distorting the signal. The notion is obviously important in telecom and other areas where the phase relationships are critical, but to call this a "distortion" in audio is certainly not appropriate.

If I follow Geddes correctly, then linear distortions surely are important in the audio acoustic realm and it matters not if they are produced by the speaker or the electronic gear, as far as the listener is concerned.

My question to SYN08 wasn't formed very well and perhaps that's why he didn't answer and that's fine.

Perhaps a general question to anyone might be better:

Do we know if reasonable quality consumer audio electronics and better, produce linear distortions?

Yah, I edited it. There were a couple of egregious mistakes.

 

[john curl]

Please, fellow audio designs, being 'picky' as to whether something is more apparent at higher levels or the opposite is really missing the point.
Capacitors with high DA will change the path as you might see it on an oscilloscope, typically 1-3% for each cap. What happens then, when you put 5 such caps in series on each channel?
Wavebourn, doesn't know, doesn't measure, and likes what he likes
SY quibbles over the laws of physics.
Syn08 thinks that I am speaking BS.
What we really need is someone to put 5 isolated RC time constants in a SPICE simulator
You need two 'identical' branches, EXCEPT that C is ideal on one branch, and the other branch uses less than ideal caps composed of the linear model put forth by Pease, or Dow before him.
Please understand that we need a high DA model for mylar, aluminum, or ceramic, and NOT the model of polystyrene, used by Dow. Then we subtract the two models and see what is left.

 

[Wavebourn]

Wavebourne,

The point of the reference I posted, which is a good piece of research by a respectable scientist, is that our sensitivity to linear distortion increases in a non-linear fashion as SPL increases, not, as you write,

Respected scientists may make mistakes in conclusions about causes of effects, especially when their explanations don't work according to respected engineers who build real things.

Wavebourn, doesn't know, doesn't measure, and likes what he likes
SY quibbles over the laws of physics.

Wrong.
I don't use caps with high DA where non-linear capacitance may add more distortions then the rest of the path because suspect that high DA may signify high level of non-linear capacitance. Why should I measure what I don't use? And yes, I like what I like. Do you like what you don't like?