Squeezebox Touch Question for Audiophiles

[konut]

While I agree that some of these prices are ridiculous, this argument is not a very good one. This is assuming that the only thing a power cord can affect is what is coming in from the wall into the device. Frequently this is not the case.

I have done a lot of experimentation on this and find that a very large percentage of sound changes due to power cords are the effect the cords have on the transformer resonances in the box.

Almost all transformers have fairly high Q resonances in the ultrasonic area, right where switching supplies and silicon diodes emit noise, thus stimulating these resonances. This ultrasonic noise can wreak havoc in many pieces of equipment.

The power cords are an important part in determining the resonance frequency and Q of these resonances.

Not only does the result of these resonances cause problems in the device the cord is plugged into, but it can also travel through the cord into other boxes, stimulating THEIR transformer resonances. (this is not wild fancy, I have measured this many times)

The net result is that a power cord CAN have a significant affect on the sound of a stereo system. The problem is in correlating it to anything. Since each system is different with different combinations of transformers its very difficult to make recommendations as to which cord design is going to be "better" than another. An expensive cord may very well sound better than a cheap one, but it may also sound worse.

The best way to deal with this is to damp the transformer resonances in the boxes themselves, its not hard to do, but hardly any manufacturers DO it. I think primarily because nobody knows its a problem. Its a significant affect that for some reason seems to have completely flown under the radar of the audio design community.

So you can either damp the transformers in all your boxes, OR spend time playing with different power cords until you find a combination that reduces the resonance affects.

BTW these resonances are electrical, NOT mechanical, rubber washers and the like isolate mechanical resonances not electrical ones.

So there you have it, I have measured significant differences in audio systems due to power cords, but I have not been able to come up with any decent correlations as to what type or design is any better at reducing the noise.

John S.

This is extremely enlightening! Is it ok to quote this on other audio fora when the subject of power cord discussions come up?

[KingKong]

This is extremely enlightening! Is it ok to quote this on other audio fora when the subject of power cord discussions come up?

Only if you want to look like a complete moron. I find it wholly ironic that your avatar claims "No BS" and yet you fell for a load of it.

Virtually everything you've quoted is complete nonsense and has no basis in reality. If JohnSwenson has done so many measurements, perhaps he'd be kind enough to share them here. I'd love to see the data surrounding the "transformer resonances."

[konut]

Hi King, and welcome to the forum! Thank you for a most enlightening first post! Can I quote you on other audio fora?

[Phil Leigh]

Only if you want to look like a complete moron. I find it wholly ironic that your avatar claims "No BS" and yet you fell for a load of it.

Virtually everything you've quoted is complete nonsense and has no basis in reality. If JohnSwenson has done so many measurements, perhaps he'd be kind enough to share them here. I'd love to see the data surrounding the "transformer resonances."

What's the word I'm searching for... I think it has 4 letters in it... :-)

[KingKong]

What's the word I'm searching for... I think it has 4 letters in it... :-)

Daft? It certainly fits quite a few posters here.

[JohnSwenson]

Take a look at this article, this is what got me looking at this subject in detail:

http://www.hagtech.com/pdf/snubber.pdf

Let me get this straight, you do not believe that transformers have resonances? Ok so lets go over a few simple questions. What is a transformer? Its two coils of wire. What is one of the main properties of a coil of wire? Its called inductance. How are the coils made? They are wires covered in insulation, so we have conductors separated by insulation. What is that? Its called a capacitor. When you put an inductor and a capacitor together you get an LC resonance. Thats the way the universe works, it wasn't invented by audiophiles.

So if you believe that transformers don't have resonances, who's being daft?

John S.

[Goodsounds]

You've fallen into the argument abyss of the engineering/analytical types vs the subjectivists. There's no common ground for discussion, it's pointless.

People who calculate and analyze often cannot accept that a measurement or theoretical difference doesn't necessarily translate into a perception difference. Often, yes, but not always. People from the subjective camp don't care about theoretical or measurement differences, they assess with their ears. Much has been studied about how the various psychological and perception anomalies in brain function can contribute to perceived apparent "differences" or "effects" when none actually exist.

Personally, I'm from the second group, but I'm happy for the gearheads to keep the economy moving with large expenditures for things I find unnecessary. It's otherwise harmless.

There's room for everyone, so long as you don't try to convert people from the other side.

[adamdea]

You've fallen into the argument abyss of the engineering/analytical types vs the subjectivists. There's no common ground for discussion, it's pointless.

People who calculate and analyze often cannot accept that a measurement or theoretical difference doesn't necessarily translate into a perception difference. Often, yes, but not always. People from the subjective camp don't care about theoretical or measurement differences, they assess with their ears. Much has been studied about how the various psychological and perception anomalies in brain function can contribute to perceived apparent "differences" or "effects" when none actually exist.

Personally, I'm from the second group, but I'm happy for the gearheads to keep the economy moving with large expenditures for things I find unnecessary. It's otherwise harmless.

There's room for everyone, so long as you don't try to convert people from the other side.

Very intriguing. I was under the impression that the measurement school more often argue that their measurements demonstrate the absence of a genuine difference resulting from subjectivist endorsed tweaks. Or to put it another way, it is more often subjectivists who argue for expensive gear which objectivists see as doing nothing (or nothing positive). Examples which come to mind from this very forum are the debate about whether a linear psu can make any difference to a digital transport, and the usual wranglings about cables. I accept that it is possible for an objectivist to argue that a difference in measurable performance might justify buying a product that subjectivists see no benefit in, but it rarely comes around that way. I don't reckon that many Nordost Valhalla purchasers are keen measurers.
John's position seems to be a rather interesting post-objectivist revisionism which on a number of issues finds measurements which might possibly support subjective impressions that eg cables or linear psus work. However (and I hope I am not misrepresenting John here) he concedes that these measurement differences do not appear to support the thesis that eg changing cables or linear psus will have predictable or even predictably positive effects on any given system.

If I ever win the lottery I intend to endow the first chair of meta-audiophilology

[Goodsounds]

Very intriguing. I was under the impression that the measurement school more often argue that their measurements demonstrate the absence of a genuine difference resulting from subjectivist endorsed tweaks. Or to put it another way, it is more often subjectivists who argue for expensive gear which objectivists see as doing nothing (or nothing positive). Examples which come to mind from this very forum are the debate about whether a linear psu can make any difference to a digital transport, and the usual wranglings about cables. I accept that it is possible for an objectivist to argue that a difference in measurable performance might justify buying a product that subjectivists see no benefit in, but it rarely comes around that way. I don't reckon that many Nordost Valhalla purchasers are keen measurers.
John's position seems to be a rather interesting post-objectivist revisionism which on a number of issues finds measurements which might possibly support subjective impressions that eg cables or linear psus work. However (and I hope I am not misrepresenting John here) he concedes that these measurement differences do not appear to support the thesis that eg changing cables or linear psus will have predictable or even predictably positive effects on any given system.

If I ever win the lottery I intend to endow the first chair of meta-audiophilology

My comment was incomplete, I agree with what you're saying, both objectivists and subjectivists can be blinded by their own brand of voodoo.

[JohnSwenson]

My take is that I HAVE been able to hear differences in power cords, and I have been able to measure something which seems to have a decent correlation to those subjective observations (transformer ringing). What I have NOT been able to do is find any decent correlation with the price of said cords.

In my own system I have properly damped all my transformers so the ringing doesn't happen at all. In this situation I have not been able to hear any differences in power cables, so I use cheap ones on everything.

I personally prefer figuring out ways to completely eliminate something from the equations rather trying to figure out how to optimize it. Its usually ultimately a lot cheaper, although not nearly as much fun as "the quest for the ultimate power cord" or whatever.

John S.