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Power cable conductor shapes?

post #1 of 12
Thread Starter 

Example: http://www.psaudio.com/shop/ac3-power-cable/

 

Quote:
Inside the AC3 is one OFC hollow conductor for the treble region, a large OFC rectangular conductor for the midrange and multiple gauges of OFC bundled together for the bass. Equipment powered with an AC3 enjoy a significant improvement in sound quality over any stock power cable.

 

 

 

Seriously?  Truth or snake oil (aka lying).

 

:blink: 

post #2 of 12

Do you really need to ask?

post #3 of 12
"Inside the AC3 is one OFC hollow conductor for the treble region, a large OFC rectangular conductor for the midrange and multiple gauges of OFC bundled together for the bass."

Should be an arrestable offence to write such crap!
(No, not really. It has its entertainment value, I guess.)
Edited by Mambosenior - 3/7/14 at 5:14pm
post #4 of 12

Indeed. There should only be "bass" wires. You want only the pure AC (50 Hz or 60 Hz) to pass through the cable. You do not want any midrange or treble frequencies (caused by noise sources such as light dimmers, or waveform distortion caused by SMPS) to pass through the cable. Even if we accept their claim that the multiple conductors will preferentially carry the different frequencies, the cable will potentially sound worse than a regular cable.

post #5 of 12
Quote:
Originally Posted by omigawsh_lollercoaster View Post
 

Example: http://www.psaudio.com/shop/ac3-power-cable/

 

 

 

 

Seriously?  Truth or snake oil (aka lying).

 

:blink: 

 

The most sensitive scientific instruments don't bother with any of this BS, and they cost WAY more than anything in audiophillia.

 

Cheers

post #6 of 12
Quote:
Originally Posted by Don Hills View Post

Indeed. There should only be "bass" wires. You want only the pure AC (50 Hz or 60 Hz) to pass through the cable.

The only way that would happen is if you're powering an incandescent light bulb.

Linear power supplies don't draw continuous current but instead draw current in short pulses (illustrated by the gray portions in the drawing below). In a full wave rectified supply, the pulses occur at twice the power line frequency, so they'll be at either 100 or 120 Hz. And because they're pulses, there will be harmonic components well above those frequencies.

This isn't intended to justify the "design" of the power cord in question, just to point out that things aren't quite so simple is all.



se
post #7 of 12

I'm all too aware of that. The problem is that the PSU design assumes an undistorted input. All too often, we don't get that any more with the wholesale change from resistive loads to SMPS loads, which at their input usually have the same diode-capacitor configuration you described. My post was partly tongue-in-cheek, in reality the cables I mentioned won't perform significantly differently than "standard" cables at the frequencies concerned for power transfer. As for harmonic generation, that's what line filters are for - to stop the harmonics getting in or out.

 

You have aroused my curiosity, though. I'll have to spend a bit of time with Spice and see how much effect a low-pass series filter has on the performance of a classic diode-capacitor design, especially when the input waveform has significant amounts of distortion (flat topping).


Edited by Don Hills - 3/8/14 at 4:29pm
post #8 of 12
Quote:
Originally Posted by Don Hills View Post

I'm all too aware of that. The problem is that the PSU design assumes an undistorted input. All too often, we don't get that any more with the wholesale change from resistive loads to SMPS loads, which at their input usually have the same diode-capacitor configuration you described. My post was partly tongue-in-cheek, in reality the cables I mentioned won't perform significantly differently than "standard" cables at the frequencies concerned for power transfer. As for harmonic generation, that's what line filters are for - to stop the harmonics getting in or out.

You have aroused my curiosity, though. I'll have to spend a bit of time with Spice and see how much effect a low-pass series filter has on the performance of a classic diode-capacitor design, especially when the input waveform has significant amounts of distortion (flat topping).

Im curious if you've done your spice investigation and if you will report your results.

Cheers
post #9 of 12
Quote:
Originally Posted by ab initio View Post


Im curious if you've done your spice investigation and if you will report your results.

Cheers


No and yes.  Work is the curse of the drinking class... :)

post #10 of 12
Quote:
Originally Posted by Don Hills View Post
 


No and yes.  Work is the curse of the drinking class... :)

:beerchug:

post #11 of 12

Hmm well in Australia at least, overhead power lines are round and underground power cables are triangular.  So maybe if you took your amp over to your mate's house who had underground power and you have overhead, it will sound different... More pointy I imagine...

post #12 of 12

If anything we would want to low-pass filter those power supply current pulses.  While some people agonize or a fer percent power line voltage THD, If you look at a big amp's AC input current's waveform it might have 200 % THD.

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