One Cord To Rule Them All

Sad, but true.

@thyname

Oh, boy.  Someone needs to take a few deep breaths and recite some mantras; I clearly pushed a button which apparently turned off their brain and made them forget what was being discussed.

The OP asked for advice regarding a 5ft power for a very expensive power quality device that acts something like a UPS without the battery backup component.  It converts the power to DC then back to AC, and puts AC at nominal, with a perfect sine wave and without power quality distortions such as voltage fluctuation.  Furthermore, the OP specifically mentioned the criterion that it be able to handle 600W continuous.  

Someone else wrote that a 7 or 9 gauge cable would be sufficient.  All I said was that the 5’ 7 or 9 gauge cable is not going to have any noticeable impact on current delivery.  C-u-r-r-e-n-t d-e-l-i-v-e-r-y.  I spelled it out since using all the letters together didn’t work the first time. 

Notice please that we are NOT talking about audio components.  We’re talking about current to a power regenerator.  That is the thing, you know, that fixes all the power problems, or at least the voltage-related ones (sag, swell, transients) and waveform distortion, i.e., harmonic distortion.  I would just posit that if such a component were itself to have its performance lessened by waveform distortion and/or voltage fluctuation then we need to have a completely different discussion about PS Audio and its technology.

Consequently, none of the subsequent litany of “misconceptions” is in any way relevant to what I posted.

As for Caelin Gabriel, I read the DTCD Measures Up” paper.  Really interesting and I recommend it; it’s provided good food for thought.  And what’s even more interesting is that he lives in the same tiny town (Poulsbo) as my former boss.  Their two companies were in the same industrial park!  I wouldn’t be surprised if they knew each other, having both worked with the Navy and being in similar fields.

Anyway, in this paper he talks about the how different power cords deliver and respond to a transient burst of current over very short periods of time (50 microseconds).  A cycle is 1/60 of a second,  the equivalent of more than 330 of these small bursts.  He is trying to simulate the way that power supplies draw current in very quick pulses.  To this end he has developed a measuring device called a DTCD (dynamic transient current delivery) Analyzer.  He takes lots of interesting measurements showing the differences that cable size and type, as well as connectors, can make over a short (3') length of cable.  He claims to be able to measure a difference if the cable length is changed even just an inch.

It’s a very well written interview by Michael Fremer, and what CG says makes sense.  It’s all about current delivery - a LOT of current delivery - over tiny intervals.  In his graphs he’s measuring instantaneous current peaks of up to 300A.  Remember that a standard residential service in the U.S. is 200A total.  300A is a crapload of current.  The OP’s 600 watts is just 5A at nominal voltage.  A typical 20A circuit breaker can handle a current peak of 125% before it trips. 

 I have to wonder what a realistic instantaneous current draw is for a piece of audio equipment.  And I admit that I don’t fully grasp the significance of such short interval current draw.  Caelin talks about switched mode power supplies (SMPS) and full wave bridge rectifiers.  SMPS use pulse-width modulation (PWM) to regulate the voltage in intervals of a cycle.  PWM is used in amplifies, dimmers, and all kinds of controls systems where changing the voltage regulates some kind of output.  But even a 1% interval in a cycle (which is very small) is still more than three times larger than the entire 50 microsecond interval that CG is graphing with his cool device.  

I just don’t know enough about the intervals that amps draw current at to draw theoretical conclusions about an associated impact on sound.  The fastest amplifier I’ve ever read about is the Sansui AU-X1, which has a rise time (the time it takes the waveform to get from 10% to 90%of its final value) of 0.5 microseconds - an order of magnitude below what CG is measuring, and a slew rate (rate of change or slope of the signal waveform) of 260V/microsecond.  The Krell Evolution (just to pick something completely randomly) has a slew rate of 120V/microsecond.  Rise time isn’t published.

This leaves me with lots to think about.  But I still don’t see how an expensive power cable is going to make any difference to what comes out of a well-designed, high end power regenerator like the PS Audio.  

Very good write up @lostinseattle! It's up to the OP. He can either 1) read all the technical white papers he can find in the Internets, even better, get an engineering degree while at it, or 2) try a PC for his power regenerator.

I suspect #2 is easier. At least for me. Especially if it involves no risk (i.e. lending library from the Cable Co.)

@cleeds 

The only way to ascertain expertise on Agon is to judge a user’s posting history.

Mostly true but another way to help understand a poster's perspective is to take a look at their virtual system.  For example, I use inefficient speakers and big power amps so I am certainly not the person to listen to regarding high efficiency speakers and single-ended triode amplifiers, other than I have said I wish I had started out with more efficient speakers.  It is both interesting and informative to look at the virtual systems here, and fun too.  While I have no problem with people who do not post their virtual systems, when they do that information sometimes helps me understand where they are coming from.

Right. It does help to understand where people are coming from. It also helps to try and understand what the heck they are saying. Lost wrote a long one, that someone thinks is good, in spite of the fact the whole thing has already been answered. The conclusion:

I still don’t see how an expensive power cable is going to make any difference to what comes out of a well-designed, high end power regenerator like the PS Audio.

Was answered back on page one of this thread:

Because nothing ever is perfect. Obviously. So no matter how good a conditioner, regenerator, or power supply, until and unless it is perfect then it will always matter what is done upstream.

The power cord coming into the regenerator will matter for the simple reason the regenerator converts the AC to DC and back to AC in real time. As long as it works this way then there will always be some ripple or artifact from the original power source. The only way to avoid this is to use AC to charge a battery, disconnect the battery from AC, and run the system off battery power.

Anything else, any scheme whatsoever that relies on the unit remaining connected to AC will always inevitably pass some amount of that AC variance on to its output.

I won’t spell it out because it does no good. People either understand plain English or they do not. This happens because no power supply regenerator or otherwise is perfect.