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 Post subject: Mains Power Cord
PostPosted: 30 Aug 2012, 19:55 
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Joined: 30 Aug 2012, 19:36
Posts: 1
i see that the person who helped in showing us how to build a main power cord ,does not believe that an audible difference can be heard ,except maybe a reduction in noise. well recently someone came over my home to listen to music and he brought with him an audiophile power cord that i connected to my threshold stasis 500 power amplifier. we all heard a tremendous improvement in all areas of the sound. i immediately bought this power cord. it was 1.5m and was only $140. but my point is ,is that i really am newly enjoying my system. and its only the power cord that we changed. amazing.


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 Post subject: Re: Mains Power Cord
PostPosted: 01 Jan 2013, 06:40 
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Joined: 16 Mar 2012, 11:15
Posts: 76
Location: UK
I can't understand how a power cord can make such a difference to the audio to be honest. The power has travelled many miles to get to the socket in your house. The last 2 metres of cabling shouldn't make a difference unless it's in a massively noisy EMF environment. Which cable did you go for?


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 Post subject: Re: Mains Power Cord
PostPosted: 01 Jan 2013, 14:34 
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Joined: 08 Aug 2009, 03:11
Posts: 2133
Location: Chilliwack, BC
If I can't measure it, it doesn't exist ;)

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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 02:27 
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Joined: 06 Jun 2008, 18:23
Posts: 4800
Location: Australia
Heed wrote:
I can't understand how a power cord can make such a difference to the audio to be honest. The power has travelled many miles to get to the socket in your house. The last 2 metres of cabling shouldn't make a difference unless it's in a massively noisy EMF environment. Which cable did you go for?

A Melbourne Audio Club (MAC) member paid a lot of money for a power conditioner and power cords. He claims it did nothing at all. He then bought some special power cords and claims every time he used they there is a very determinable difference in the sound. He said a big improvement in all facets of the music. I trust his judgment. The cords are made from solid core copper, not used here in Australia any more and are very stiff.

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Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "Mimic Carbon" - carbon resistors and PIO caps. MM phono preamp
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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 10:42 
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Joined: 04 Jun 2008, 20:59
Posts: 3510
Location: Arizona, USA
Hi All, A lovely topic to cause disruption in the world. I agree with the comments in part. It is quite true that the 20 miles to the power station will introduce all sorts of trash in the AC lines and a goodly bit of it will find its way into the audio system if you do nothing about it. However, if you have a really good power line filter / conditioner it will block a vast majority of it. Then there is a small chance that what you use to connect the filter to the equipment might make some difference. The key words are some, slight and might. Since everything I design has EMI filters on the AC inputs and I do have a high quality power line filter on my system I have not been able to detect any difference in what power cords are between the filter and equipment. My system is dead quiet for all sources at all power levels. I use short IEC computer cables. Your results might be different, but unfortunately the fault that is supposedly being fixed is IMHO more likely a design deficiency in the equipment. In which it has either none, or ineffective input filters. The cable then most likely has both significant inductance and capacitance and will to some extent act like a power line filter. For me personally, I find it a better deal to put $15 power line filters in all my gear than to spend $150 on cables to each.

BTW Happy New Year, May it be a good one for you. :wizard:

Good listening
Bruce

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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 11:35 
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Location: Chilliwack, BC
gofar99 wrote:
Hi All, A lovely topic to cause disruption in the world.


Yep, cable topics need to be treated like politics and religion :lildevil:

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* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 12:38 
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Joined: 06 Apr 2009, 10:08
Posts: 1375
Location: US Pacific Northwest
Heed wrote:
I can't understand how a power cord can make such a difference to the audio to be honest.
Neither could I. For a long time I had heard about this topic and dismissed it as wishful thinking and marketing. Until one day it was demonstrated to me (I insisted on a blind test). :blush: The fancy expensive power cables actually sounded better. To say that I was perplexed is an understatement!

However, being a good Engineer I decided that some investigation was in order. Upon opening up my friend's very expensive SS amp, some rather interesting things became apparent. When we talk about how amps operate we almost always make assumptions concerning the power supply; foremost among them that the PS has a near zero impedance at all frequencies and supplies constant voltage regardless of load. This way we can focus on the amp design and not worry about things like voltage sag and varying impedance.

The amp in question was a large SS affair with a large PP output stage biased heavily into the AB region. This amp when pushed even moderately will draw significantly more PS current than at idle. So turning to the power supply we found the culprit. The PS in question consisted of a simple input filter, a SS bridge, one electrolytic capacitor, a simple pass element regulator and and one small cap on the regulator output. Nothing more. There was no energy storage to speak of (either capitative or inductive). In short, the amp's audio circuitry was essentially connected straight to the mains. Then we looked at the power cord supplied with the amp, it was 8 feet long and used 18AWG wire. A quick check verified that even under moderate loads the PS saw significant sag when using this cord (especially at low frequencies). When the new cord was used (6 feet with 14AWG wire) there was considerably less sag in the supply and the amp did indeed sound significantly better, especially its low end performance.

In short, although the new cord did make the amp sound better, it was because the new cord significantly lowered the output impedance of the (very poorly designed) power supply, not because the cord was some magical mix of secret technologies. It was exactly as Bruce indicated above...
gofar99 wrote:
Your results might be different, but unfortunately the fault that is supposedly being fixed is IMHO more likely a design deficiency in the equipment.
I suspect that there are a significant number of amps on the market with this particular type of deficiency. But if you have one, the answer may simply be larger gauge wire; which can be done for a few dollars and a couple of cord ends.

This also reenforces the lesson that attention must be paid to the power supply designs we use for our amps. If not correctly designed, they can significantly limit the overall performance of the amplifier.

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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 13:06 
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Joined: 04 Jun 2008, 20:59
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Location: Arizona, USA
Hi, Verging on OT, I put as much effort in power supplies as I do in the main circuitry. Often the PS has far more components than the active circuit. I have seen a lot of gear with the simple sort of PS you describe. Cheap design = cheap sound IHMO.

Good listening
Bruce

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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 17:26 
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Joined: 06 Jun 2008, 18:23
Posts: 4800
Location: Australia
I also have filters in all my power amps. Because lately my preamps use a wall wart then another tranni as a step-up I don't use a power filter here. All my AC or power cords have good size ferrite chokes near entrance to the gear. I do believe my power amps started sounding so much better then I started using power filters.

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Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "Mimic Carbon" - carbon resistors and PIO caps. MM phono preamp
Website: retro-thermionic


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 Post subject: Re: Mains Power Cord
PostPosted: 03 Jan 2013, 22:51 
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Joined: 28 May 2008, 21:53
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Location: Winnipeg, CANADA
Good discussion. ;)

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