In reading both posts, I thought it odd I would have to repeat myself...but I realized that some of my info is on another thread over at AH. Pardon my confusion and the times where I add onto material you may not have seen..
Originally Posted by FOH
Do you base your assertions about Shunyata, and the individuals that produced this white paper, solely on the data contained in this white paper? Or are these assertions drawn from an aggregate of information that you've attained about Shunyata, and more specifically this author, via many sources?
It is based on what I know about the topic, the way they describe it, the way they approach it, the way they test it, and the way they interpret the results. I do not have any information on the authors or engineers who worked on this project, so my assertions are in no way colored by previous history. However, I do stand by my assertion that they have performed nice and elegant work even if they missed the mark in the initial premise.
1. They have assumed that audible differences in line cords is caused by the ability (or lack thereof) to supply current to the power supply at the microsecond level and 200 plus ampere level. This of course requires the wall outlet be capable of providing this
.tech goop alert
Assume 12-3 romex, 50 feet, prop velocity half lightspeed (2nSec/ft),characteristic impedance 100 ohms, load panel infinite current capability, line voltage 100 volts...keep the numbers simple..
Connect a .5 ohm resistor across the line instantly (t = 0)
at t=0, the current in the resistor? 1 ampere, with a 99.5 volt negative V step travelling to the panel.
at t=100 nS, the entire line is charged at a level of .5 volts, the negative 99.5 volts reflects inverted at the load panel and begins back. the line is again charging to 100 volts...but now the load panel current is 1.995 amps.
at t=200 nS, the 99.5 volt hits the load, adding .995 amps to the load, it now has 1.995 amps, and about -98 volts starts the journey to the LP.
At t=400 nS, the load current rises another amp (give or take), load at 3 amps..
At t=600nS, Iload=4
800nS, 5 amps
1 uSec, about 6 amps..granted, it is actually slower, as the add on keeps getting lower and lower.
This is an initial current slew rate of 6 amps per microsecond..225 amps would require almost 40 microseconds to build up. This is governed by the speed of propagation of the romex. I've neglected the 1.7 milliohm per foot for #12, or .17 ohms, that would cause an IR drop of 38 volts...leaving 62 volts available long term, or 124 amps absolute maximum..not 200 in this example.. edit:yes the actual Imax is 100/(.5 + .17), or 149 amps...the IR drop can't result from 200 amps...(I said I'm a nitpicker, even to myself)
Clearly, the test does indeed show the cord's ability to support high current slews, but it's like a V-8 engine on a shopping cart.. This aspect of the test is truly consistent with the miles and miles argument that has been tossed into the fray.
And I've neglected the supply cap ESL, the input transformer parasitic inductance, and the bridge rectifier bulk resistivity..
In essence, the assumption they make of the supply being starved, is inconsistent with the overall system.
Rather, the test they have designed is actually measuring the total energy storage of the cable being tested. For non constrained cables (not coaxial or stripline), this measure is actually a measure of the total magnetic field external to the cable. This external cable is very capable of coupling to the system ground loop. They need to re-focus to that, as that is where the ball is.
Originally Posted by FOH
...... my question to you is would you show all of your cards in ad copy disguised as a white paper?
On another forum, I stated that they wish to give enough technical to attract the target audience, but not enough to duplicate for a while. I have no problem with that.
They are good, but they are playing with the wrong deck. (note: a full deck of course, just not the correct one.)
Originally Posted by mntmst
All this is fine and correct, but it's like talking about how the arrangement of pink flamingos on your front lawn affects the power and position of a hurricane.
If one considers the problem in the "miles and miles" vein, then I agree with you. However, they are altering the external magnetic field of the cable as well as the internal capacitance, and are therefore altering the coupling to the ground loop. That is a different beast entirely..the data they provide via their test is inconsistent with a real life setup.