I took a quick glance at this thread. Lot's of fun.
Quite a few scoff at people's obsession to spend big bucks on cable lifters.
Years ago, I tried listening to power cable lifted off the floor. Like original poster, was surprised by what seems a positive outcome. To this day my power cord is uncerimoniously lifted about 3" off the cheap industrial carpet that adorns the man cave / stereo room. I use disposable cups. lip side down with a 'V' cut out of the bottom to hold the cable. Started with Tim Hortons (its a Canadian thing) paper cups. My wife said, pleaaaase get rid of the coffee cups. So now use clear plastic poly cups which are mostly invisible.
But they remain in my room looking rediculous now for 5 years because... drum roll please... it sounds better. When I knock them over without realizing it. I get a couple of tunes into my listening with an unpleasent sense that something is not right. Sure enough getting the cord off the carpet does the trick.
No money required. 3 or 4 trips to the coffee shop and you are in business. I suspect Dunkin Donuts (a USA thing) will work equally well... For the elite, try Starbucks.
Quite a few scoff at people's obsession to spend big bucks on cable lifters.
Years ago, I tried listening to power cable lifted off the floor. Like original poster, was surprised by what seems a positive outcome. To this day my power cord is uncerimoniously lifted about 3" off the cheap industrial carpet that adorns the man cave / stereo room. I use disposable cups. lip side down with a 'V' cut out of the bottom to hold the cable. Started with Tim Hortons (its a Canadian thing) paper cups. My wife said, pleaaaase get rid of the coffee cups. So now use clear plastic poly cups which are mostly invisible.
But they remain in my room looking rediculous now for 5 years because... drum roll please... it sounds better. When I knock them over without realizing it. I get a couple of tunes into my listening with an unpleasent sense that something is not right. Sure enough getting the cord off the carpet does the trick.
No money required. 3 or 4 trips to the coffee shop and you are in business. I suspect Dunkin Donuts (a USA thing) will work equally well... For the elite, try Starbucks.
Yes, it's as simple as that ... thrashing around about the cost of doing this in audiophile approved fashion, or delving into the subtleties of transmission line behaviour is completely missing the point ...
Yes. In this case, when rise time >> tprop latency is simply the time constant L/R and the shape of the waveform is conserved.
Nothing wrong with the HP bridge per se, just need to be aware of its properties, such as 50R series impedance between source and load, and its rated bandwidth.jneutron said:
Yes, because L depends on line length, and in your terms rf line impedance and prop velocity depend on L per length. In practical terms for audio bandwidth and domestic speaker cables the delay will be L/R where L is cable inductance and R is load resistance - for a resistive load.jneutron said:
What you are describing at audio bandwidth, jn, is simply a property of cable inductance. And in any event effects are negligible and swamped by typical load inductance.
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A brief recap of the last 25 or so pages for those too busy to slog through:
(jn) Is too!
(ltd) Is not!
(jn) Uh huh!
(ltd) Nuh ahh!
(jn) Sez you!
(ltd) Oh yeah?!
(jn) Is too!
(ltd) Is not!
...
(jn) Is too!
(ltd) Is not!
(jn) Uh huh!
(ltd) Nuh ahh!
(jn) Sez you!
(ltd) Oh yeah?!
(jn) Is too!
(ltd) Is not!
...
Might seem like that, kevinahcc20, but between the lines there's subtle evolution in what is accepted, and convergence I think, albeit slow. I think one ought to think about and test what JN posts, and its nothing if not interesting even if one might disagree with it - it's well constructed.
None of this cable theory discussion has included effects of insulations, or effect of ferrous or non ferrous materials intercepting the radiated field of the cable.
This is the crux of this thread.
IME, lifting cables away from contact with the flooring can make an audible difference.
Dan.
This is the crux of this thread.
IME, lifting cables away from contact with the flooring can make an audible difference.
Dan.
Yes, I think it's implicit that the extent to which either lumped cable parameters or TL properties (depending on pov) might vary with proximity to floors/objects d'art etc is relevant to understanding any real effect. Or if one can take likely variation params x10 and predict no effect, it also says something probably.
Thanks, but what your rudimentary single cell model is missing is the relationship between the line and the load impedance.
You see, we need to be more exacting than a simple rudimentary model.
From your previous post, it's clear you are stuck on the RC and RL time constants to the detriment of actual physical understanding. That's ok, in fact, that's how they actually want the engineers. It's actually by design that they want good engineers to remain stuck with approximations and simple models. As, when it gets too complex to understand, good engineers can fall back on the simple models taught to them.
Some people, on the other hand, have to go beyond the simplistic models. You think of L as inductance. I do not. L is the equational relationship between the current in a system and the magnetic energy stored in the system. Many engineers cannot wrap their head around that..and that's ok.
That is why simple models were developed..they come close, but don't explode your head...
jn
You really need to understand what he has written, not just read it. There's many concepts there that are quite accurate, but are simply above the target audience level of understanding.
You need to figure out where the simplistic approximations you believe in fall apart. You seem to have made the simplistic approach a religion, to the demise of accuracy. Again, that is what they teach in EE class..
I'll take a pic of the low impedance bridge page and put it up, I believe two pages should suffice.
jn
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That is precisely why I keep mentioning the COI I am burdened with, and why I had mentioned a long time ago, a collaborative effort.
jn
That argument falls apart as the line impedance approaches the load.
You challenged it's applicability to the problem. As I said, using it with a low impedance load doesn't negate the reflection coefficient, it only inserts losses. Cyril built a low z device, and duplicated the results from the 50 ohm bridge.
And yet, how many speaker or cable vendors describe, test, present the effects that either the lumped parameters or t-line parameters can have on the delay at the load vs frequency, and the fact that cables can impact the delay to the tune of audibility if poorly selected?
Do you really think my purpose here is to teach T-line theory??
It's all about imaging, and what affects it, and what levels of temporal control are needed.
You are but a pawn...Bwaaahhhaaahhaaaa (mad scientist laugh).
Seriously though, I'm pretty sick and tired of the vendor garbage about "95 % lightspeed", low z cable being the end all, making the cables with magnet wire and spacing them a foot apart to make wonderful changes, or twisting them tightly for wonderful changes, or lifting off the carpet for wonderful changes, or wrapping them in carbon for wonderful changes..
The problem is one of what we are sensitive to, and how the solutions change the response...T-line is more exacting than lumped, obviously so, but some like you are more than happy with the approximations.
jn
LINE CORD lifters.....really??? sigh..😀
What you are experiencing is a ground loop. The physical layout of your cordage is trapping magnetic field, and it is being conducted into your equipment. I have absolutely experienced this, but did not use lifters as a solution. Go to my gallery, look at the ground loop drawings.
There is no EMC standard for ground loop/line cord current/input isolation. The closest the industry has come has been Whitlock. But he's not presented a standardized testing scheme that audio equipment manu's can use to debug problems like what you are experiencing.
You are not crazy, I would expect there can be audible differences as a result of the manipulation you are trying. But it is not the lifters per se. It is a sensitive ground loop.
Oh....the existence of a ground loop does not mean hum will be present. The ground loop is a structure which traps time varying magnetic fields and turns it into current. What gets trapped is what counts.
jn
Absolutely.
With cable lifters and things like carpet, proximity to a rug will change the capacitance but not inductance. If the inductance is very high, which means capacitance is very low, proximity to a carpet will change the prop velocity by changing the cable's characteristic impedance.
My solution would be to drop the cable z, which by definition reduces inductance, raises per foot capacitance, but forces the fields of the cable to be more confined. This reduces any effect of proximity.
jn
Like luckythedog, I believe Bateman needs to understand what he has written - then correct it.jneutron said:
Are you redefining inductance to mean something other than inductance? If so, further discussion may not get very far. If not, why say it at all?
If someone uses circuit theory in a situation where circuit theory is appropriate he is not being "simplistic". If someone uses full EM wave theory in a situation where circuit theory is appropriate he is not demonstrating greater understanding.
Hmmm ""he's wrong, but I can't tell you why.""
Yah, that works.
Why not give bateman a call and teach him.. I'm sure he takes calls from internet guru's all the time..
First, you'll probably need to familiarize yourself with the equipment..and the tests, and...well, pretty much everything he did...you wouldn't want to come across as, well, an internet guru wannabe.
Inductance is the relationship between the current in a system, and the magnetic energy stored in that system.
Certainly you do not need a primer, no?
Or, as you and lucky have demonstrated, read an article (davis) which has internal inconsistencies, and grab onto it as gospel because it's what you want to believe.
jn
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So you are still not posting about audible issues with cable lifters.
All this for what?
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