Steve Eddy said:
And that's because you prefer to look at it in this way. I may prefer to define a black box between the amp (the black box output) and the mains (the black box input) and conventionally assign voltages and currents at the terminals, as per the quadripole formalism. The I may look into the black box and write the differential equations that are characterizing this quadripole, tieing the voltages and currents at the terminals. The party pooper is the rectifying bridge, which makes the whole quadripole non-linear, but I could still write only linear differential equations by splitting the time domain in chunks depending on the diode state (open/blocked) and tie these equations by writing the electrokinetic conservation time border conditions. Add the t=0 initial conditions and you got a nice set of equations that certainly has a unique solution.
Is the input (mains) current depending on the output (amp) load? Can't answer unless we define precisely "depending"...
Certainly, under quasistationary/permanent load regime (that is, considering the load current time independent/DC and allowing enough time for everything to settle down after connecting the load), we'll get a nice 60Hz periodic input current, drawn from the mains. If we also consider the finite mains source impedance, we could also calculate the input voltage periodic time dependency. However, we don't need to solve the differential equation set to estimate the average input current; the energy conservation law will provide a quick response to this question.
However, in the more complicated case of a time dependent load current (e.g. the amp is playing music), the input current will also depend on the load current variation in time. How much, it's difficult to answer analytically. Certainly, the caps do play a filter role here (mapping to an exp(-t/tau) factor in the current equations), not allowing most of the load current variation to propagate at the input, but as long as caps are finite, this kind of dependency will still exist. Now, should we care about? We may, if the mains source impedance is not zero. The current dependency will result in a mains voltage dependency, which may propagate e.g. to the preamp. If the preamp has poor PSRR, it is theoretically possible to get kinda feedback, 'cause the mains may modulate the preamp output, which is modulating the amp output, which is modulating the mains, etc...
Should we care about such mechanisms? Let's get real... Unless the mains is extremely poor wired, dimming the lights when the amp is playing music, and the audio chain has a very poor PSRR, this is a red herring. Under normal circumstances, anybody that claims hearing such mains effects is either disillusional or a swindler, trying to sell you some $1000 pure recristallized silver mains cable, blessed by tibetan monks. You'd better want to spend that kind of money rewiring your home...
john curl said:
John, may I ask what relevance this has to anything I've said?
If I've said something you believe is incorrect, then simply point it out and explain why it is incorrect.
The last time we debated, you demonstrated that you didn't know quantum theory from a hole in the ground.
Tell us, John, what in quantum theory states that electrons are not charged particles and that they are not the charge carriers responsible for electron current flow?
se
SY said:
No, it was inquisitory.
I was trying to get at what exactly it was that John was trying to say.
I think he's just got his straw men mixed up. Some time ago on another forum he claimed that I still believed in the "planetary" model of the atom (i.e. the electrons orbiting the nucleus in nice neat little orbits) during one of his many attempts to try and impugn me by making false claims about me.
This "charged marbles" thing is a new one on me and I was just curious what it was he was trying to say as he seemed to be saying something which to my knowledge hasn't been "superceded" by quantum theory.
se
Actually, fellow designers, I was trying to convey one of the secrets of my audio 'success' in making products that people actually like, often above the typical audio product. I do not even pretend to be the best of designers, because as often as not, Nelson Pass, Charles Hansen, and even Audio Research, beats me out in some way or quality of performance, or whatever.
I am only trying to convey some of the approaches that have worked for me to improve my designs over the decades.
However, it is almost impossible for me to do so, unfortunately.
'J'accuse' the moderators also for allowing this to happen for so long.
All I want to do is to express my design opinions in a constructive way to help others on this website. Nothing more.
I am only trying to convey some of the approaches that have worked for me to improve my designs over the decades.
However, it is almost impossible for me to do so, unfortunately.
'J'accuse' the moderators also for allowing this to happen for so long.
All I want to do is to express my design opinions in a constructive way to help others on this website. Nothing more.
Everyone who wanted to get deeper would certainly like to consider that the energy is transferred by electromagnetic field ALONG the wire. There is no electric field inside the ideal wire with infinite conductivity, though there is some electric field inside the real world wire. The speed of propagation there (inside the wire) is pretty slow, depends on frequency, conductivity, permitivity and permeability. For Cu, the propagation velocity is only 2,9m/s at 50Hz.
Anyway, this was obviously not the case here.
Anyway, this was obviously not the case here.
Steve Eddy said:
Steve,
You would be right if you mean a galvanic current flow. That is not the case here, but I think all would agree that the currents in the speaker can only flow because of the currents from that pole transformer. So, there is an undeniable connection between the speaker current and the pole transformer current. One influences the other.
I think John's saying that the speaker current returns to the mains neutral is technically perhaps not fully correct, but we should all be smart enough to deduce the words that were left out. I'm pretty clear what he meant, and he has a point. And I'm sure you also know what he meant. It's impossible to start each post with "there was this man called Ohm, and he discovered...".
You made your point. You made us all sit up and think. Can we now move on?
Jan Didden
janneman said:
Well sure there's a "connection" in that current flowing in the AC mains is responsible for supplying the energy to charge the caps for the amplifier to provide current to the loudspeaker.
But you might just as well say that there's a connection between the amp's output current and the sun which evaporates the water which falls as rain which fills the reservoir which spins the turbines of the generator which produces the power on the AC mains.
It wasn't the words that were left out, it was the words that were put in. Return path. Specifically, ground return path. More specifically, the amplifier's ground return path. I think most of us know what that means and it doesn't mean just some "causal" connection as you relate above. Nor apparently is that what John intended it to mean as when I pressed him to explain exactly what he meant by "ground return path" he cited Wikipedia, which says "a common return path for electrical current."
No, I honestly still don't quite know what he meant. And everything that he has said in response to my querying him to try and understand what he meant, has pointed to his having the notion that there is an actual, galvanic, ground return path between the amplifier's output and the AC line.
That's not what I'm expecting at all. All I'm expecting is that if someone says something and it isn't quite clear, that when they're asked exactly what it is they mean, that they give a simple, straightforward answer, and not turn it into a series of riddles, guessing games, and vague "look it up" Easter egg hunts.
se
Nope, that's not a good analogy at all. Especially since the primary and secondary are electromagnetically coupled with a time constant that makes such a coupling essentially instantaneous.
Steve, if I were a cynical guy, I'd think you were more interested in scoring debating points than being illuminated. But you know me, not a cynical bone in my body.
Steve Eddy said:
No, this was a really, really big solid state thing that a couple of guys here wanted to build. A thousand watts or something like that. They spent a lot of money on parts and made some progress, but I believe they ran into various (personal, not electronic) difficulties and the project was mothballed. I'm not sure about its current status.
Grey
SY said:
It wasn't intended to be an analogy per se. What I was saying when I said that was that I didn't think the sun connection had any more to do with what John was talking about than what Jan was saying John was talking about.
Jan said "You would be right if you mean a galvanic current flow. That is not the case here..."
Given all that John had said in response to my querying about the "ground return path" I believe that it is the case and that John wasn't just talking about "causal" connections. I bring this up in the subsequent two paragraphs in my reply.
What are you talking about? Your cynical bone is HUGE! Last time you were down here I thought you were packing heat. Though I didn't think you would be stupid enough to put a gun THERE of all places.
se
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