Power cables - am bewildered!

[arj]

Here is some reading material for all on power cords.. all from audio asylum

1. Do they make a difference
2. How they affect sound
a) Do they make a difference
b) Power cord sound
3. length of Power cords
4. how they could make a difference


And finally

Tests for power cords

This is very interresting. It shows that the difference between power cords could be as much as 35dB peak in spots!

The difference between power cords is on average rather small- about 16 dB (noise floor to average value), but it can be rather sizeable in spots. A level at -55.42 dB is a lot of musical power. If you remember the average for the whole original music sample was around -17dB with max loudness at -10dB RMS. What this means is that there are differences between power cables that can be heard starting only at 40dB below average level in audio material. Or so I see it. Please correct me, any EE's out there, if I'm wrong.

 

[arj]

OT, but to lighten things up:

arj, I like your signature line. I wonder which category I fall under.

you will need to ask Bertrand Russell...too bad he is dead

 

[asliarun]

There is one question that bothers me in all this. I'm sure it has been asked numerous times but I'll ask again because I haven't seen any answers yet.

If the quality of input electricity makes a big difference to the quality of sound, why don't power amplifier manufacturers take the appropriate steps to guard their equipment against it? They go to incredible lengths to guard the purity of the signal inside the amplifier itself. It seems absurd to think that they would not give any thought (or sufficient thought) to this fundamental aspect of their amplifier design - or that they would not have sufficient protection built-in.

I don't pretend to be an engineer although I do have a degree to that effect. However, it seems that if "the last few meters or power cable make a huge difference", as an engineer, the first thing I would is to put a few meters of high quality cable inside my power amp before I feed the electricity to my power amp circuitry.

This would be a really easy way for me (as an engineer) to guarantee that the "last few meters of cable" are fully in my control (and indeed, inside my amp!). And everything outside my amp (literally everything outside the 3 pin female socket of my power amp) would be considered "the outside world" that is beyond my control. I would be able to treat the amp's power cord as if it were part of the electrical grid.

And please, no more ad hominem attacks. A lot of us are reading/posting on this thread out of genuine scientific temper and I have little interest in berating anyone or the other way around.

 

[Thad E Ginathom]

Here is some reading material for all on power cords.. all from audio asylum

1. Do they make a difference
2. How they affect sound
a) Do they make a difference
b) Power cord sound
3. length of Power cords
4. how they could make a difference


And finally

Tests for power cords

I think this is what they made the tl;dr abbreviation for :lol:

I have begun many a multi-hour browsing session from HFV --- but heading off to four threads on another forum, which seems to be designed to hard to read, is more than I can cope with just now. I'm sure there are gems in there. Jon Risch seems to have some interesting stuff to say, and it would be good to have the engineers' responses. Isn't he the guy that Lucas (Lampizator) mentioned in the article posted early on in this thread re the simple, cheap filter?

There is stuff about voltage drop there. Can anyone explain (Hello Kanwar? ). If that is all correct, then would it not work just to use the same or thicker cable than that in the wall? Isn't it always going to be the "worst" bit of [nearby?] cable that counts?

The comparison test, too, in your final post is certainly deserving of better-qualified eyes and brain cells

Couldn't take it all in just now, but it still stimulated questions

 

[Nikhil]

... However, it seems that if "the last few meters or power cable make a huge difference", as an engineer, the first thing I would is to put a few meters of high quality cable inside my power amp before I feed the electricity to my power amp circuitry.

In a sense yes this should be the way its done but cost considerations affect the extent to which it is done. The higher you go into audiophile territory the more you see extensive measures in the way the power section is handled. Given labor costs in the west, this does not come cheap.

You also have the situation where one has already made the investment on a particular system. Power cords here offer an opportunity to extract that "next level" of detail or sound quality that appeals to the listener. This is a purely subjective area where the question is not about does the power cable make a difference but rather what is the difference when one uses so and so cable.

 

[Santy]

@asliarun
I had a similar doubt and posted my query earlier. Why do high end audio manufacturers who know how each of the 100s of components they use to make their reference audio equipment affect its sound quality, have not focused on the power cord as much as an aftermarket power cord manufacturer has engineered them? If the cost is so high to manufacture them (though for an expensive audio gear, it would be still feasible), they could atleast keep it as an upgrade option.


Meanwhile, some interesting observations in this page:
Myths and Snake OIL : Empirical Audio

If the power supply in a given component has enough energy storage built-in with a low-inductance path to provide current to the electronics, then an improved power cord will have little or no effect. It is therefore primarily under-designed and inferior power supplies in audio components that will benefit from improved power cords. From experience, however, we have found that virtually all power amps benefit from a low-inductance power cord.

Power Cord Shielding
Shielding of power cables serves no useful purpose. Shielding will add significant capacitance to the cable with minimal positive benefit. If you really need this, then the shield should be spaced well away from the conductors (large diameter) to minimize capacitance and avoid constraining the magnetic field lines that should couple between the conductors. Empirical testing has shown that standard shielded 14 gauge stranded power cord sounds less dynamic than unshielded 14 gauge stranded cord. The impedance of the electrical system is extremely low and susceptibility to magnetic and RF fields is extremely low for power cables so the benefit is questionable at best.

 

[sidvee]

I have a Lamm ll2.1 deluxe preamplifier. This is the only preamplifier I have had (had Conrad Johnson, ARC etc prior), that was impervious to power cords or power line conditioners. And also one of the few manufacturers who suggests not using a PLC. This is the recommendation on their website for owners of Lamm eqpt:
"Do you recommend using power line conditioners
with LAMM equipment?

All LAMM models are equipped with internally built power line filters of high quality. From our experience, our power amplifiers work better when connected to the wall socket directly, without any external filers or line conditioners. This assumes that one is using a dedicated power line. Of course, if one's mains has electrical noise above reasonable levels then power conditioners may be used.

The same applies to our preamplifiers."

So yes there are equipment that are immune to higher end power cords/line conditioners and yet there are others that benefit. So generalization is difficult and there is a certain amount of subjective interpretation involved on the part of the listener as I suggested in my earlier post. However due to the power quality in India, I still am using a servo stabilizer and a power line conditioner though my listening room has a dedicated supply from the mains.
Cheers,
Sid

 

[kanwar]

If the quality of input electricity makes a big difference to the quality of sound, why don't power amplifier manufacturers take the appropriate steps to guard their equipment against it? They go to incredible lengths to guard the purity of the signal inside the amplifier itself. It seems absurd to think that they would not give any thought (or sufficient thought) to this fundamental aspect of their amplifier design - or that they would not have sufficient protection built-in.

Cannot say much about home audio amp designers and their priorities towards power cables and noise rejection. But i can point you towards various examples in Pro-amps which have dedicated mains filtering built in which works both ways i.e. Filtering out Garbage from Line to Amp and Stopping the contamination of Line from Amp. Its 2 way thing IEC 61000-3-2 are very stringent european norms one has to follow in Pro -Audio sector.

The above picture is from Crown Pro-amp, there you can see the adequate measures taken for that very purpose. Three green cores and Blue box caps, its called EMI filter, it contains Differential as well as Common Mode filter. This acts as a barrier for the garbage.

Check the Black Cores In Zypher Amp, Bottom side, 2 per section, total Eight. They are just for filtering purpose and the Power Factor Correction is achieved by the coils under round Green PCB.

There is stuff about voltage drop there. Can anyone explain (Hello Kanwar? ). If that is all correct, then would it not work just to use the same or thicker cable than that in the wall? Isn't it always going to be the "worst" bit of [nearby?] cable that counts?

Thad,

Making a low inductance cable is not at all difficult,remember Twisting?. It actually lessens the impedance of the chord and rest is what you see in some tests and differences to hear. There are otherways to do it also such as Interleaved Twisting which is more used in Broadcast Industry than home audio. Since you can do this with normal bare conductors of Finolex cable also, its achievable at much lesser price, why to go for exotics and pay for something which is simple to do. The materials don't effect EMI/RFI, the geometry is what makes the inductance/impedance variation. Twisting is one way if doing it.

@asliarun
Meanwhile, some interesting observations in this page:
Myths and Snake OIL : Empirical Audio

Pretty much kicks hard the proponents of Snake oil.

Nice "Relevant" Link

 

[kanwar]

"Do you recommend using power line conditioners
with LAMM equipment?

All LAMM models are equipped with internally built power line filters of high quality. From our experience, our power amplifiers work better when connected to the wall socket directly, without any external filers or line conditioners. This assumes that one is using a dedicated power line. Of course, if one's mains has electrical noise above reasonable levels then power conditioners may be used.

The same applies to our preamplifiers."


Cheers,
Sid

This simply reinforces what i already said in previous posts , Make and design the equipment in such a way that you don't need Band-Aids later.

 

[kanwar]

You also have the situation where one has already made the investment on a particular system. Power cords here offer an opportunity to extract that "next level" of detail or sound quality that appeals to the listener. This is a purely subjective area where the question is not about does the power cable make a difference but rather what is the difference when one uses so and so cable.

So in otherway around its like if someone has spent a good amount on its system which is LACKING in power supply area[presuming he swapped different power chords to find that difference] and then he finds that a certain power cable makes a huge difference, so must be applied as Band-Aid[Rather then going for an equipment which is not affected by power cables at all]....What say, Irony here is that he cannot go on spending each time for a new system but is happy to spend a good amount on power cables everytime :clapping:

 

[shanmune]

This simply reinforces what i already said in previous posts , Make and design the equipment in such a way that you don't need Band-Aids later.

Kanwar,
While I am trying to understand some of the technical details you have put, I have 2 quick questions.
1. When you say "radiated EMI", is it that it radiates from the power cable (due to the flow of power) and that radiated EMI has an impact on the performance of the near-by audio components ? That's what my understanding is, but just wanted to confirm with you.

2. Does this "radiated EMI" applicable for speaker cables as well ? If so, to what extent will it have an impact on the near-by audio systems ?

3. I was originally planning for a DIY speaker cable (around 14 AWG) using nominal cost Finolex cables and I raised a related query as well in another thread, but I didn't get any response. Here is the link which gives us some simple steps to make that. This is albout using the right thickness and twisting the wires appropriately to offer reduced inductance. Of course, this is for speaker cables.
Low-Inductance DIY Braided Hi-Fi Speaker Cables

In my post in the other thread, I was trying to find a reason on why one should opt for costly speaker cables when there was a easy and cheaper way to do a good cable, but unfortunately I didn't get any response.

As you said, if getting a decent and thick enough power cable (and twisting it), then that would be a wiser option to have the power cable at a reasonable price. Actually, the power cable I have has a plug following some Europe standard and that wasn't compatible at all with the Indian socket. So I was planning for a while to replace it. So if you say getting a thick finolex cable and twisting would be more than enough, then I would proceed that way.
Thanks !!!

 

[sidvee]

This simply reinforces what i already said in previous posts , Make and design the equipment in such a way that you don't need Band-Aids later.

But the real question is how many manufacturers actually do this? Like I said earlier in the 4-5 preamps I have owned (in the past decade) only Lamm has this design (or at-least advertises it). So hence the proliferation of PLC's, power cords, power related accessories etc. And being that the power supply is a major cost component in an equipment, that is what will be cut in many budget products which will then in turn benefit from aftermarket products. So the industry as a whole is propagating this, not just users.
Cheers,
Sid

 

[keith_correa]

For claimed effective rejection of external RFI/EMI try a Maillot braid. Look it up. If you can't find information, let me know and I'll dig it up from my notes and post details. Can be used for IC's too. Whether it works or not - I'm not going there. Suffice it to say that my system is maybe not resolving enough

 

[kanwar]

Kanwar,
1. When you say "radiated EMI", is it that it radiates from the power cable (due to the flow of power) and that radiated EMI has an impact on the performance of the near-by audio components ? That's what my understanding is, but just wanted to confirm with you.

Yes, higher the voltage, higher the current draw thru the cable, higher will be the radiated EMI, higher will be its impact on near by sensitive audio gear.


2. Does this "radiated EMI" applicable for speaker cables as well ? If so, to what extent will it have an impact on the near-by audio systems ?

Radiated EMI is always produced when you have the high voltage with high current flow. In home audio, the speakers are not of much power nor are the amplifiers, so the radiated EMI from speaker cables will be much much less then what you have with Mains AC cable. So its impact would be much lesser.

3. I was originally planning for a DIY speaker cable (around 14 AWG) using nominal cost Finolex cables and I raised a related query as well in another thread, but I didn't get any response. Here is the link which gives us some simple steps to make that. This is albout using the right thickness and twisting the wires appropriately to offer reduced inductance. Of course, this is for speaker cables.
Low-Inductance DIY Braided Hi-Fi Speaker Cables

That link is displaying the technique known as Interleaved Twisting which results in lower inductance and better transient response. Good thing to make something productive and achievable with simpler means.

In my post in the other thread, I was trying to find a reason on why one should opt for costly speaker cables when there was a easy and cheaper way to do a good cable, but unfortunately I didn't get any response.

How many are good at DIY-ing their own cables, i guess not many and some people go after Brands to nurture their huge egos, hence a brand is must and the makers of cables exploit that very fact to earn huge profits out of the ignorance.

As you said, if getting a decent and thick enough power cable (and twisting it), then that would be a wiser option to have the power cable at a reasonable price. Actually, the power cable I have has a plug following some Europe standard and that wasn't compatible at all with the Indian socket. So I was planning for a while to replace it. So if you say getting a thick finolex cable and twisting would be more than enough, then I would proceed that way.

Go for it and enjoy the DIY-ing

Thanks !!!

I hope this helps.

 

[arj]

So in otherway around its like if someone has spent a good amount on its system which is LACKING in power supply area[presuming he swapped different power chords to find that difference] and then he finds that a certain power cable makes a huge difference, so must be applied as Band-Aid[Rather then going for an equipment which is not affected by power cables at all]....What say, Irony here is that he cannot go on spending each time for a new system but is happy to spend a good amount on power cables everytime :clapping:

you have a very valid point on PS, but most equipment meant for Home audio -that takes prices to stratospheric heights...so while it may be suboptimal, the bandaid option is more effective economically.

At least for me, individual components do have their own sonic signature and as it is getting the entire chain to work together as one system with the required sonic signature is a pain...add to that availability and budget constraints.

Now adding the power supply design also is only going to make this impossible...so only option could be the "band aid"

pro audio just does not cut it for me...and the only one i can dream of would be ATC actives..and thats too expensive.

 

[kanwar]

But the real question is how many manufacturers actually do this? Like I said earlier in the 4-5 preamps I have owned (in the past decade) only Lamm has this design (or at-least advertises it). So hence the proliferation of PLC's, power cords, power related accessories etc. And being that the power supply is a major cost component in an equipment, that is what will be cut in many budget products which will then in turn benefit from aftermarket products. So the industry as a whole is propagating this, not just users.
Cheers,
Sid

Sid,

Isn't that good if some manufacturer gives you something which is of vital importance for the performance...?

And yes i agree, that there are some manufacturers who are equally responsible for making cheap products which on other hand needs the usual band-aids to get good results.

But don't you think one must educate itself to someextent and buys a better product which has the said components and takes cares of many important factors in one go?

Home audio sector/products doesn't have stringent norms to follow unlike pro-audio world. Thats why those manufacturers do such kind of things.

I have never seen Branded Class-A amps subjected to mains harmonic contamination norms but a pro-amp has to pass that norm otherwise it cannot enter the market and that norm by default takes care of this garbage IN/OUT thing in a unique way.

 

[keith_correa]

The above picture is from Crown Pro-amp, there you can see the adequate measures taken for that very purpose. Three green cores and Blue box caps, its called EMI filter, it contains Differential as well as Common Mode filter. This acts as a barrier for the garbage.

Looks serious. Some of my audiophool friends in the US use Crown amps in their home. Never understood why

Check the Black Cores In Zypher Amp, Bottom side, 2 per section, total Eight. They are just for filtering purpose and the Power Factor Correction is achieved by the coils under round Green PCB.

Any chance of us mere mortals laying our hands on one of these PSU's?

 

[sidvee]

pro audio just does not cut it for me...and the only one i can dream of would be ATC actives..and thats too expensive.

And Arj, that is the case for many listeners as well. Otherwise there would be no Home Audio/Pro Audio distinctions, they all would be one and the same, and again there will be arguments that pro audio is accurate and home audio is colored ...... which is another inconclusive thread at best:lol:...... and has been beaten to death many times over in other forums.
Cheers,
Sid

 

[kanwar]

you have a very valid point on PS, but most equipment meant for Home audio -that takes prices to stratospheric heights...so while it may be suboptimal, the bandaid option is more effective economically.

At least for me, individual components do have their own sonic signature and as it is getting the entire chain to work together as one system with the required sonic signature is a pain...add to that availability and budget constraints.

Now adding the power supply design also is only going to make this impossible...so only option could be the "band aid"

pro audio just does not cut it for me...and the only one i can dream of would be ATC actives..and thats too expensive.

I agree with you on that Band-aid option, because the home audio manufacturers give you ZERO option in that aspect and one has to choose the band-aid way. Agreed.

But the shameful thing occurs when the people don't acknowledge this fact and start making statements which are pseudo-science.

 

[sidvee]

Sid,

Isn't that good if some manufacturer gives you something which is of vital importance for the performance...?

And yes i agree, that there are some manufacturers who are equally responsible for making cheap products which on other hand needs the usual band-aids to get good results.

But don't you think one must educate itself to someextent and buys a better product which has the said components and takes cares of many important factors in one go?

Home audio sector/products doesn't have stringent norms to follow unlike pro-audio world. Thats why those manufacturers do such kind of things.

I have never seen Branded Class-A amps subjected to mains harmonic contamination norms but a pro-amp has to pass that norm otherwise it cannot enter the market and that norm by default takes care of this garbage IN/OUT thing in a unique way.

I agree Kanwar, that one must educate oneself, but then one must also like the sound quality produced by equipment as well. I agree not all home audio produces good sound, but similarly not all pro audio produces good sound. Please see my earlier comment on Pro Audio vs Home Audio, and I will let it rest at that.
Cheers,
Sid