I've been looking through of HiFi forums recently only to discover the rediculas discussions on offer. Like how different power leads make a difference to the sound of your system? I mean how does it? There is no electronic theory explanation is there?
I love of this diy community is immune to this pointless and stupid topics like these!
I love of this diy community is immune to this pointless and stupid topics like these!
Possible explanations:
1. they don't make any difference.
2. they affect the amount of RF pickup, which can affect unfiltered equipment.
3. they have a marginal effect on charging pulse shape and hence harmonic generation.
I will leave the 'true believers' to offer their alternative explanations. Given the miles of cable from the power station, and hundreds of metres from the local supply transformer, and tens of metres within the house, it is astonishingly unlikely that any significant change can be effected by the last two metres!
1. they don't make any difference.
2. they affect the amount of RF pickup, which can affect unfiltered equipment.
3. they have a marginal effect on charging pulse shape and hence harmonic generation.
I will leave the 'true believers' to offer their alternative explanations. Given the miles of cable from the power station, and hundreds of metres from the local supply transformer, and tens of metres within the house, it is astonishingly unlikely that any significant change can be effected by the last two metres!
I'm sure the very little changed by the last two meters won't compare to the things connected to it and where they are in the room and such.
4. all cables have real components like resistance, inductance and capacitance. Therefore cable will act as filter (or as pickup) and last two metres of cable are much more important than hundreds of meters before.
Differences are audible and expensive cables are not always better.
But no power cord can transform your POC amp to the SOTA amp 😀
Differences are audible and expensive cables are not always better.
But no power cord can transform your POC amp to the SOTA amp 😀
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Why? This could just about be true if the main problem was high microwave pickup which was attenuated quickly by lossy PVC insulation. Then the last 0.5m might matter. To improve things we could choose an even worse dielectric.
If you care to measure 1/3 to 1/2 of the total AC power line resistance is in the power cord and connectors!
But it is mostly the RF filtering that can be done in a cord without increasing power loss as an inductor would do that is the biggest asset.
But it is mostly the RF filtering that can be done in a cord without increasing power loss as an inductor would do that is the biggest asset.
But how does that compare with the transformer resistance? In most cases probably negligible. However, a high mains lead resistance will help reduce current rise times and so reduce mains harmonic generation. Use the thinnest lead which will not melt with the current! (OK, I'm not being entirely serious - we are talking about a very marginal effect).
The transformer resistance is inside the magnetic loop and has less of an effect than circuit theory would show.
Just a question: have there been irrefutable blind tests performed by a neutral and competent body, such as a reputable university lab confirming the materiality of the effect?
This is the minimum proof standard that can be demanded in such a highly contentious issue.
This is the minimum proof standard that can be demanded in such a highly contentious issue.
I'd be willing to bet most audible effects come down to simple things, such as 'audibly good-quality' cords using reasonable-quality connectors. So much equipment uses the utterly miserable IEC 320 connector with its sloppy fit and lack of control over pin tension etc. that it makes using even 18ga. wiring and similar more than adequate.
Me, I use commercial (Volex) 240VAC /10A moulded IEC leads , cut down at the mains plug end (UK, 240V 13A and rewirable) to just the lengths I need. I like these over the supersilly things I have tried / been lent almost entirely because the moulded IEC connector appears to grip tight and reliably - that's all.
(And yes I have been nerdish enough to 'scope the differences from wall socket to internal transformer wired input, across the entire mains cord/switch loop)
Me, I use commercial (Volex) 240VAC /10A moulded IEC leads , cut down at the mains plug end (UK, 240V 13A and rewirable) to just the lengths I need. I like these over the supersilly things I have tried / been lent almost entirely because the moulded IEC connector appears to grip tight and reliably - that's all.
(And yes I have been nerdish enough to 'scope the differences from wall socket to internal transformer wired input, across the entire mains cord/switch loop)
Could you expand? I'm sure you are not suggesting that transformers don't obey circuit theory!simon7000 said:
Circuit theory is a model of what happens. The R in the transformer primary in a circuit model tries to include all loses not just winding resistance, but core, eddy losses, etc.
Even the DC resistance of the primary coil is not the current limiting factor of a properly working transformer.
Have you ever measured the DC resistance of an audio power amplifier power transformer? Then try measuring the secondary loaded and unloaded. Two measurement points will allow you to assign an equivalent R loss value, but if you do say ten of them the I V line is not straight!
Of course. I didn't just mean DC resistance but other contributions too. Nevertheless, if these signficantly exceed the cable resistance (which will almost always be true) then the cable resistance will have little effect on the charging pulse shape. This is still true with non-linearity present.
The power amp on my bench has a DC resistance of .6 ohms. That is less than the power wiring in many locations.
The DC resistance of the transformer primary is not relevant to this discussion. A 500VA transformer running at full power on a clean 120 volt sine wave source will have about 29 ohms impedance which is much higher than any reasonable power cord and/or mains wiring.
Mike
Mike
I once bought an old used table saw and the seller pointed out it has a "medical grade" power cord. Someone had replaced the original cord, but I was only buying it because of the custom steel stand and Beismeyer (sp) fence.
oohh RF immunity, another bullet point for selling features me thinks. Most well designed gear already has built-in RF and noise rejection, Maybe it's just the "High End" esoteric gear with poor PSRR and wonky power supply designs that could possibly benefit. It is NOT really the last 3 ft there is also the wire inside the box and circuit topology that determines the last 99.9%. Most accessories are the dealers bread and butter the pitch is usually best made when yer wallet is already open.
oohh RF immunity, another bullet point for selling features me thinks. Most well designed gear already has built-in RF and noise rejection, Maybe it's just the "High End" esoteric gear with poor PSRR and wonky power supply designs that could possibly benefit. It is NOT really the last 3 ft there is also the wire inside the box and circuit topology that determines the last 99.9%. Most accessories are the dealers bread and butter the pitch is usually best made when yer wallet is already open.
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It's got me totally stuffed how (except perhaps for RF rejection), but they sure can. Self-proclaimed objectivists are entirely free to convince themselves otherwise.
And by stating that I am not implying that expensive (or even modestly priced) aftermarket replacement leads are by any means a good idea or investment.
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No it isn't , in fact I could point you to a number of threads w200 plus posts for yer amusement. but I guess you searched and read lots already. Everybody talking past each other, coming from different worlds and languages. Like the post following mine. I'd love to hear his explanation of RF on line cords and sound quality.
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