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Nordost Valhalla AC Power Cables, I've been reading a lot about them...
Funkstar De Luxe
post Aug 3 2004, 18:56
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It seems these AC cables are being praised in just about every HI-Fi magazine I pick up. Aparently they provide better timing (no, I don't know what that meant either), better dynamics and deeper bass. At $2500 a piece they better had.

I'll get to the point now. I don't understand why the cable to the power supply in the component (amp, CD player etc) would have any effect on the sound. The electricity runs though all different kinds of crap cables to get to your house and somehow placing 2 meters of very expensive cable at the end of that chain make a different? I don't think so. Sure, good quality cable to hook everything up is vital - after all it's your actual audio that's runiing though them. But an audiophile mains lead?

Can some one please tell me a logical/scientific explanation of how this works? Is there one? Anyone actually heard the difference a good power cord caqn make to their system? It seems like a load of shit to me but there is just too many reviews and publicity for it to be completely false.

Tony


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jaustin
post Aug 3 2004, 19:22
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QUOTE (Funkstar De Luxe @ Aug 3 2004, 12:56 PM)
Can some one please tell me a logical/scientific explanation of how this works?  Is there one?  Anyone actually heard the difference a good power cord caqn make to their system?  It seems like a load of shit to me but there is just too many reviews and publicity for it to be completely false.
*


I think it's impossible to answer part of your question without violating TOS #8. But I'll try to answer the part I can answer by quoting the available reasonable arguments, none of which I have verified. IMO, in audio there's very little you can rule out on the basis of simplistic technical arguments. A/C power cords are a case in point. Still, $2500 power cords are absurd and completely unjustifiable.

Do they make a difference in the sound? Sorry, can't anwer that (TOS#8). Is it possible that they do? Absolutely. Expensive power cords can, in principle, act as filters for high frequency nasties on the power lines. These nasties are often generated by digital equipment, sometimes in your stereo system. CRT computer monitors are also very bad. The worst source in my house is a cheap range with a digital control panel. A cord with a ferrite-impregnated jacket can act as a filter for high frequencies. I'm not claiming that the cord you mentioned actually does this, but it's possible. Also, heavy shielding can reduce the nasties that could get into the supply via radiation, via the cord acting as an antenna. It's well documented (see, for example, the classic book by H. Ott) that such nasties can adversely affect the operation of various types of electronic equipment.

Another factor is that by modeling an typical amplifier circuit you can see that the peak current in the power cord far exceeds the RMS value. That's because the power supply only "recharges" at the top of the A/C cycle. You can get some rather intense current peaks, exceeding the RMS value by a factor of 10 or 15. The result can be a very significant reduction in voltage as a result of resistive losses in a typical 18 gauge power cord and its associated imperfections (poor crimps, etc.). These very fast current pulses can also create high-frequency nasties, which can feed back into the A/C in the absence of shielding and filtering.

Those are (some of) the arguments, and I find them reasonable, though they certainly don't justify paying $2500 for a power cord. I don't know electronics that well, but I have a physics Ph.D.

Jim Austin

This post has been edited by jaustin: Aug 3 2004, 19:25
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WmAx
post Aug 3 2004, 19:41
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QUOTE
Those are (some of) the arguments, and I find them reasonable, though they certainly don't justify paying $2500 for a power cord. I don't know electronics that well, but I have a physics Ph.D.


This all comes down to basic electrical/rf laws, though. The hi-end proponents specifically make their claims on supposodely 'mysterious' or 'unknown' variables. But any properly designed audio applanec should have an effective filter in the power supply. Personally I would question the value and engineering of audio equipment that required a special pwer cord that had special filtering properties in order to function properly.

-Chris
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jaustin
post Aug 3 2004, 19:51
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QUOTE (WmAx @ Aug 3 2004, 01:41 PM)
This all comes down to basic electrical/rf laws, though. The hi-end proponents specifically make their claims on supposodely 'mysterious' or 'unknown' variables. But any properly designed audio applanec should have an effective filter in the power supply. Personally I would question the value and engineering of audio equipment that required a special pwer cord that had special filtering properties in order to function properly.
-Chris
*

True, it all comes down to electrical/rf laws, but I don't know about "basic". Finding the answers to some of these questions would require careful experimentation and possibly modeling. As for questioning the value and engineering of audio equipment that requires a special power cord to function properly, I agree with you up to a point. There's some very expensive, very poorly engineered equipment out there. But I'm less inclined towards the polarized view this implies: good engineering wouldn't benefit at all, lousy engineering might. There's a lot of middle ground here between great and lousy, and many widely available products may fall in the middle...and consequently may benefit the extra filtration/reduced losses an aftermarket power cord might provide. There are some easy tests you can do, though visual ones are often easier than audible ones. Try using a good A/C filter on your television while watching a DVD. If your power is clean you may not notice a difference. But if the power isn't clean ... If A/C nasties can interfere with a DVD player's electronics, why not with a CD player or an amplifer?

Jim
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Posts in this topic
- Funkstar De Luxe   Nordost Valhalla AC Power Cables   Aug 3 2004, 18:56
- - boojum   Can you spell B-U-L-L-S-H-I-T? FWIW, many amps h...   Aug 3 2004, 19:11
- - WmAx   QUOTE (Funkstar De Luxe @ Aug 3 2004, 12:56 P...   Aug 3 2004, 19:20
- - jaustin   QUOTE (Funkstar De Luxe @ Aug 3 2004, 12:56 P...   Aug 3 2004, 19:22
|- - WmAx   QUOTE Those are (some of) the arguments, and I fin...   Aug 3 2004, 19:41
|- - jaustin   QUOTE (WmAx @ Aug 3 2004, 01:41 PM)This all c...   Aug 3 2004, 19:51
|- - WmAx   QUOTE Finding the answers to some of these questio...   Aug 3 2004, 20:00
|- - Pio2001   QUOTE (WmAx @ Aug 3 2004, 08:00 PM)WIth issue...   Aug 3 2004, 21:06
|- - jaustin   QUOTE (Pio2001 @ Aug 3 2004, 03:06 PM)I recal...   Aug 3 2004, 21:10
|- - Pio2001   QUOTE (jaustin @ Aug 3 2004, 09:17 PM)I belie...   Aug 3 2004, 22:55
|- - jaustin   QUOTE (Pio2001 @ Aug 3 2004, 04:55 PM)followi...   Aug 4 2004, 02:59
|- - jaustin   QUOTE (Pio2001 @ Aug 3 2004, 04:55 PM)If it i...   Aug 4 2004, 03:16
|- - Pio2001   QUOTE (jaustin @ Aug 4 2004, 03:16 AM)Your de...   Aug 4 2004, 11:24
|- - jaustin   QUOTE (Pio2001 @ Aug 4 2004, 05:24 AM)I disag...   Aug 4 2004, 12:25
- - Xenno   Every circuit inside an amp runs on DC. If the pow...   Aug 3 2004, 20:56
|- - jaustin   QUOTE (Xenno @ Aug 3 2004, 02:56 PM)If the po...   Aug 3 2004, 21:17
- - Xenno   Well...either you'll get an audible 50-60 Hz h...   Aug 3 2004, 22:47
|- - jaustin   QUOTE (Xenno @ Aug 3 2004, 04:47 PM)Well...ei...   Aug 4 2004, 03:19
|- - 2Bdecided   QUOTE (Xenno @ Aug 3 2004, 09:47 PM)Well...ei...   Aug 4 2004, 12:51
- - DigitalMan   My frustration with audio cables is that we rarely...   Aug 4 2004, 00:23
- - Xenno   Yeah...whatever. You'll either hear it...or yo...   Aug 4 2004, 16:12
|- - useless_engineer   Well...if you do get hum, buy a $4 length of ...   Aug 4 2004, 17:26
||- - useless_engineer   The best part about luxury audio cables is where t...   Aug 4 2004, 18:14
|||- - jaustin   QUOTE (useless_engineer @ Aug 4 2004, 12:14 P...   Aug 4 2004, 20:41
||- - jaustin   QUOTE (useless_engineer @ Aug 4 2004, 11:26 A...   Aug 4 2004, 20:40
||- - useless_engineer   QUOTE Power delivery systems (in the U.S.) are des...   Aug 4 2004, 21:04
|||- - jaustin   QUOTE (useless_engineer @ Aug 4 2004, 03:04 P...   Aug 4 2004, 21:50
|||- - useless_engineer   QUOTE but I wonder if a ferrite-impregnated power ...   Aug 5 2004, 05:45
|||- - jamesattufts   Would the whole John Dunlavy debunking of expensiv...   Aug 5 2004, 08:24
|||- - jaustin   QUOTE (useless_engineer @ Aug 4 2004, 11:45 P...   Aug 5 2004, 13:18
|||- - useless_engineer   QUOTE What it means (and I admit it might not have...   Aug 5 2004, 16:51
|||- - cabbagerat   QUOTE (jaustin @ Aug 5 2004, 04:18 AM)QUOTE (...   Aug 5 2004, 17:51
||- - Pio2001   QUOTE (jaustin @ Aug 4 2004, 08:41 PM)QUOTE (...   Aug 5 2004, 00:32
||- - jaustin   QUOTE (Pio2001 @ Aug 4 2004, 06:32 PM)If you ...   Aug 5 2004, 02:09
|- - 2Bdecided   QUOTE (Xenno @ Aug 4 2004, 03:12 PM)Yeah...wh...   Aug 5 2004, 09:33
- - CSMR   QUOTE (Pio2001 @ Aug 3 2004, 12:06 PM)I recal...   Aug 4 2004, 17:21
- - ara-fat32   Hi-fi Magazine Rules, why they can find peoples pa...   Aug 5 2004, 05:10
- - rickshaw   There is a rule of thumb in Hi-End Audio that you ...   Aug 5 2004, 09:46
|- - Pio2001   QUOTE (rickshaw @ Aug 5 2004, 09:46 AM)Just h...   Aug 5 2004, 12:02
- - rickshaw   Pio2001, As mentioned the issue at hand and the i...   Aug 5 2004, 12:45
- - .halverhahn   QUOTE (Funkstar De Luxe @ Aug 3 2004, 07:56 P...   Aug 5 2004, 13:49
- - Gecko   I have a related question. What kind of power cabl...   Aug 5 2004, 15:39
- - DigitalMan   QUOTE (rickshaw @ Aug 5 2004, 03:45 AM)Pio200...   Aug 5 2004, 16:25
- - dreamliner77   I bet we could sell some of these $2500 cable...   Aug 5 2004, 19:17
- - 2Bdecided   QUOTE (dreamliner77 @ Aug 5 2004, 06:17 PM)I ...   Aug 9 2004, 12:41


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