Power cables (for amp)
Discussion
TonyRPH said:
ian996 said:
<snip>
The Kimber cable leads were the first that I felt I could detect an improvement from (back in about 2000) and my guess is that their impact is mainly, as advertised, due to the rejection of EMI/RFI.
<snip>
So in essence what you are saying here, is that the short ~1m length of main cable is behaving as a filter?The Kimber cable leads were the first that I felt I could detect an improvement from (back in about 2000) and my guess is that their impact is mainly, as advertised, due to the rejection of EMI/RFI.
<snip>
An IEC socket with a decent filtering arrangement could achieve the same thing a heck of a lot cheaper (if mains borne RFI was really an issue).
Additionally, most transformers will themselves filter out EMI/RFI by virtue of the construction. Large power supply transformers don't conduct high frequencies very well.
Finally, if you can hear a difference it has to be measurable as there is nothing magical about audio engineering.
The power amp section of a typical amplifier needs to amplify frequencies in the range of ~10Hz to ~40kHz (top end that high not necessary but that's a topic in itself).
When presented with frequencies in the RF range (greater than 10MHz for example), a well designed amplifier should simply ignore them if the input filtering and feedback network is designed appropriately.
I've built amplifiers with very wide power bandwidths (almost full power - 100w RMS - at 500kHz) and had no issues with EMI/RFI - having even operated a CB transmitter (27MHz) in close proximity with no issues.
Any unwanted high frequencies 'sitting' on the mains network are unlikely to be greater than a few KHz, as most breakers / meters will filter those out anyway, due to the natural inductance of those devices, and any that does manage to break through will be at such a low level as to be totally benign.
Additionally, even the crappiest of switch mode PSUs inject practically nothing back into the mains these days (not that they ever generated enough grunge to be rendered audible).
So quite how 1m of mains cable can effect any kind of audible improvement escapes me (both from an engineering and audible point of view).
Ultimately, the amplifier is likely to be more at risk from air borne EMI/RFI and no mains cable will filter that out (but competent design will render it resistant to such issues anyway).
A 'click' or 'pop' on the mains may well be heard, but the spike there is huge (albeit brief).
In my opinion, when you get down to this level of "changing the mains cable" you'd be better off spending the money of making sure the room your in is acoustically correct, you'd get "more bang for your buck" as it were.
I remember working in an AV store (Tandy) we'd sell Gold plated scart cables for £49 back in 1990's I remember telling a customer they were a waste of money. He looked unhappy, I told him to go home, take the lit off his VCR and come back IF it was wired inside with gold. The thanked me for saving him £49.
All the pro audio installations i've ever worked with are usually wired with https://www.bryant-unlimited.co.uk/9001%20BLK Cheap audio cable back to krone frames. The jumper wire between all the krone blocks on the frames was https://www.bryant-unlimited.co.uk/JW%20221A Might as well be Bell wire...
Inter area multicore cabling was, https://www.canford.co.uk/Products/31-325_CANFORD-...
The screens were very rarely wired in the audio cables. We relied on the earth connector of the mains cable as all pro kit use to have an IEC with 3 pins wired.
We did have what was called a "Technical Earth" for the buildings. So studio's and Central Technical Area's CTA's had a separate earth to the rest of the building. This was done to try and isolate the earth from the likes of fan heaters and other office junk causing crap on the earth.
As equipment got cheaper (double insulated) ie no earth connector the Tech Earth became less relevant.
mgv8 said:
When the BBC LS3/5a where put tougher they where looking for a flat response. The microphone showed this but the expert ears said there was something wrong at the cross over frequency between the two drivers. The "bump" was introduced to fix this (ear over testing).
There is a lot going on and so testing is the clear way forwards. For me like the BBC engineers I can hear the difference between the cable that came with the amp and my new one.
That will almost certainly have been a phase anomaly, which of course would have been audible, but the response would still have measured flat.There is a lot going on and so testing is the clear way forwards. For me like the BBC engineers I can hear the difference between the cable that came with the amp and my new one.
Was phase even measured back then? As nearly all speaker specs from the 70's show frequency response only, and phase plays a huge part.
As for hearing mains cable differences; well, perhaps my ears are simply not golden enough.
TonyRPH said:
ian996 said:
<snip>
The Kimber cable leads were the first that I felt I could detect an improvement from (back in about 2000) and my guess is that their impact is mainly, as advertised, due to the rejection of EMI/RFI.
<snip>
So in essence what you are saying here, is that the short ~1m length of main cable is behaving as a filter?The Kimber cable leads were the first that I felt I could detect an improvement from (back in about 2000) and my guess is that their impact is mainly, as advertised, due to the rejection of EMI/RFI.
<snip>
In fact that is how I approach all modifications to my system - I test the water in a small way and, if it works for me, I follow-up in a more comprehensive manner. In terms of mains supply, I started with a few Russ Andrews power leads,then I progressed to fitting a dedicated consumer unit and a dedicated HiFi ring-main of Kimber woven cable. I now have a somewhat extreme implementation (loosely based on Ben Duncan's "Super Spur" approach), which involves four dedicated spurs, each consisting of a copper pipe containing closely mutualled and suitably over-specced live and neutral cables, running from the dedicated CU, then six metres under the listening room floor to the system. Earth's for all four spurs run adjacent to the copper pipes, via a separate set of trunking to the house "safety earth". Each of the copper pipes is also earthed at one end. Two of the spurs feed my mono power amps directly, the other two spurs feed two PS Audio P5 regenerators, which supply the rest of my components.
In fact, the implementation is actually a little more complex than the above, but its already probably too much information merely to confirm that, yes, I believe RFI (airbourne, transmitted and self generated within my components themselves) is insidious, damaging and audible. And, yes, I believe that even a short length of mains cable can alleviate the issue to some degree.
Here's the blurb on the Russ Andrews cables from the man himself, I know he is a little reviled in certain "objectivist" enclaves, but I have a suspicion he could give you a run for your money in a technical conversation:
https://www.russandrews.com/images/pdf/SuperKordTe...
I did quite a bit of investigation before embarking on the above and am quite content with both the theoretical basis of the implementation and the benefit it provides in terms of the performance of my system. I certainly wouldn't suggest the O.P. embarks on such a journey but that is where I ended up, based on my perception of the audibility of upgrading a few power leads. The PSU in both my pre and power amps have also been extensively reworked, utilising Mundorf HC+ and AG+ four-pole caps throughout in a further attempt to reduce spurious noise. This is another "tweak" which I am inordinately happy with .
I am sure that you are very capable in what you do, and if you are happy with your system and enjoy your music,that is great. I am happy with my system and I enjoy my music very much - there is absolutely no reason why our systems (or our commitment to them) should be the same. .
ian996 said:
<snip>
Earth's for all four spurs run adjacent to the copper pipes, via a separate set of trunking to the house "safety earth". Each of the copper pipes is also earthed at one end. Two of the spurs feed my mono power amps directly, the other two spurs feed two PS Audio P5 regenerators, which supply the rest of my components.
<snip>
Creating your own earth (either in conjunction with or in addition to) the existing inbound mains earth is verging on dangerous because of the different earth potentials you are (potentially, but almost certainly) creating.Earth's for all four spurs run adjacent to the copper pipes, via a separate set of trunking to the house "safety earth". Each of the copper pipes is also earthed at one end. Two of the spurs feed my mono power amps directly, the other two spurs feed two PS Audio P5 regenerators, which supply the rest of my components.
<snip>
Have a read of 'Types of earthing systems' on Wikipedia.
There are also some good videos about this on Youtube too.
ian996 said:
To take a small step back, the OP asked for comments from those who felt they could discern improvements via upgraded mains cables. As ever is the case in these parts, a few have waded in with dogmatic assertions that mains leads couldn't influence sound.
Provided the copper in the cable is thick enough to carry the required current with minimal voltage drop (e.g. like the cable that comes with the amp), there will be no sound difference. Whatever you think you hear is down to cognitive biasTonyRPH said:
ian996 said:
<snip>
Earth's for all four spurs run adjacent to the copper pipes, via a separate set of trunking to the house "safety earth". Each of the copper pipes is also earthed at one end. Two of the spurs feed my mono power amps directly, the other two spurs feed two PS Audio P5 regenerators, which supply the rest of my components.
<snip>
Creating your own earth (either in conjunction with or in addition to) the existing inbound mains earth is verging on dangerous because of the different earth potentials you are (potentially, but almost certainly) creating.Earth's for all four spurs run adjacent to the copper pipes, via a separate set of trunking to the house "safety earth". Each of the copper pipes is also earthed at one end. Two of the spurs feed my mono power amps directly, the other two spurs feed two PS Audio P5 regenerators, which supply the rest of my components.
<snip>
Have a read of 'Types of earthing systems' on Wikipedia.
There are also some good videos about this on Youtube too.
LimSlip said:
ian996 said:
To take a small step back, the OP asked for comments from those who felt they could discern improvements via upgraded mains cables. As ever is the case in these parts, a few have waded in with dogmatic assertions that mains leads couldn't influence sound.
Provided the copper in the cable is thick enough to carry the required current with minimal voltage drop (e.g. like the cable that comes with the amp), there will be no sound difference. Whatever you think you hear is down to cognitive biasian996 said:
The installation was by a qualified electrician. I am not entirely sure what you mean by "creating your own earth" I used to have a dedicated earth post for the HiFi but I stopped using that (even for earthing casework) when the regulations changed. The earths in the current set-up all connect to the inbound mains earth, they just run outside (but adjacent to) the copper conduits containing each spur's Live and Neutral. Basically, its just four spurs , all linked to the inbound mains earth.
Your post implied (to me at least!) that the copper pipes were buried in the ground.I apologise if I misunderstood.
TonyRPH said:
ian996 said:
The installation was by a qualified electrician. I am not entirely sure what you mean by "creating your own earth" I used to have a dedicated earth post for the HiFi but I stopped using that (even for earthing casework) when the regulations changed. The earths in the current set-up all connect to the inbound mains earth, they just run outside (but adjacent to) the copper conduits containing each spur's Live and Neutral. Basically, its just four spurs , all linked to the inbound mains earth.
Your post implied (to me at least!) that the copper pipes were buried in the ground.I apologise if I misunderstood.
http://www.britishaudio.co.uk/SPR-SPUR.htm
The original spec suggest armoured cable or "pyro" , armoured cable raises almost as many issues as it solves (acknowledged by BD), the copper pipes are a purer implementation. It's referred to in the above link as a "DIY" job, but its not DIY any more...needs to be signed off!
My feeling is that RF/EM interference is not wholly addressed by the mechanisms you describe in your original post, so I was just trying to illustrate that I've taken it an extra yard (or two) and am happy with the result. I'm aware that individual mileages may vary (a lot).
Edited by ian996 on Monday 3rd February 20:36
LimSlip said:
Provided the copper in the cable is thick enough to carry the required current with minimal voltage drop (e.g. like the cable that comes with the amp), there will be no sound difference. Whatever you think you hear is down to cognitive bias
You might just want to read about the electrical properties of wire. Resistance is only one property, and it has fooled many people over the years into thinking “all cables are the same”. ian996 said:
No apology necessary.
ian996 said:
My feeling is that RF/EM interference is not wholly addressed by the mechanisms you describe in your original post, so I was just trying to illustrate that I've taken it an extra yard (or two) and am happy with the result. I'm aware that individual mileages may vary (a lot).
The thing is, RFI/EMI gets everywhere, and will even find it's way into your various devices through ventilation holes, poorly jointed casework etc.Manufacturers of RF sensitive equipment go to great lengths to provide adequate shielding and ironically they don't need to use shielded mains cables, as ingress is usually prevented at point of entry (e.g. an IEC socket with adequate suppression amongst other techniques), and of course the case work is joined at the seams with fine wire gauze.
I guess what I'm really trying to say here, is that all the RFI/EMI (cable) suppression in the world won't prevent ingress into equipment.
This is actually something that could easily be measured under controlled conditions (e.g. Faraday cage).
Tony1963 said:
You might just want to read about the electrical properties of wire. Resistance is only one property, and it has fooled many people over the years into thinking “all cables are the same”.
At 50Hz AC mains, there are simply no other properties to be concerned over barring resistance.The impedance will be so low as to be utterly inconsequential.
Capacitance (parallel obviously) is of no significance either.
If your mains power supply was running at 200+ KHz then yes, there might be some (very minor) cable properties to consider, but even then...
But at 50Hz so long as the cable is capable of supplying the required current, then it's good enough.
ian996 said:
If fellow-KW owner Legzr1 is out there, rca and speaker terminals have been upgraded to WBT nextgen AG and the neutrik powercons have been upgraded from 20amp to 32amp to allow higher aggregate gauge umbilicals to the output stage.
(sighs: so much audiophile bulls
t stuff to buy, so little time (and money))
I looked at your pic and thought “that’s been fettled”!(sighs: so much audiophile bulls
t stuff to buy, so little time (and money))Off topic (Most of my cables are from Kimber; Monocle X for speaker cables, entry level stuff for the rest - I’m not about to get into a mains cable debate - mine sounds fine and that’s what matters to me but I bought a Teddy XPS PSU for my Naim Streamer - I love wasting £££...).
One of my KWs is poorly - quiet static type noises which don’t increase in volume when music level increase, followed by distortion. I’ve pinpointed one monoblock and had it to a local MF dealer/repairer. Soak tested for a week without any fault. Sods Law - a day after getting it home the same fault has appeared.
I don’t have original packaging so I’m faced with a 500+ mile round trip to drop it at Henley Designs or another 100 miles to get it to JS. Then a repeat journey to pick it up
A friend who knows a little about big amps and has recapped and fettled a few over the years had the top cover off, looked at the internal design and multi-level boards and simply replaced the cover - no way would he delve into it lol.
I’ve bought a little Quad QSP (modern version of the 909 current-dumper) to tide me over while I decide what to do and it’s amazing with the 800Ds - so much so that I’m not too worried about taking a few months to decide what to do!
There’s a local ‘man with a van’ who’s offered to pack both amps and the PSU and drop them off at Henley’s and I think I’ll do this - getting the time to do it myself is proving difficult.
Sorry, just rambling now. I love what the KWs do so sticking with them.
And I still haven’t got round to sourcing longer umbilical leads - I think JS is the man to get them from after reading of your issues with incorrectly wired cables - at least I think it was you who mentioned it?
This made me laugh: https://www.futureshop.co.uk/furutech-the-empire-p...
"Maintained optimum signal quality" - what signal comes through the mains?
"Maintained optimum signal quality" - what signal comes through the mains?
Monty Python said:
This made me laugh: https://www.futureshop.co.uk/furutech-the-empire-p...
"Maintained optimum signal quality" - what signal comes through the mains?
50Hz...."Maintained optimum signal quality" - what signal comes through the mains?
TonyRPH said:
mgv8 said:
When the BBC LS3/5a where put tougher they where looking for a flat response. The microphone showed this but the expert ears said there was something wrong at the cross over frequency between the two drivers. The "bump" was introduced to fix this (ear over testing).
There is a lot going on and so testing is the clear way forwards. For me like the BBC engineers I can hear the difference between the cable that came with the amp and my new one.
That will almost certainly have been a phase anomaly, which of course would have been audible, but the response would still have measured flat.There is a lot going on and so testing is the clear way forwards. For me like the BBC engineers I can hear the difference between the cable that came with the amp and my new one.
Was phase even measured back then? As nearly all speaker specs from the 70's show frequency response only, and phase plays a huge part.
As for hearing mains cable differences; well, perhaps my ears are simply not golden enough.
It is very easy to get a speaker to measure perfectly flat if all you are trying to achieve is a flat response, on axis, at 1m away. There are plenty of crap speakers out there that do just that.
The late, and very great, John Dunlavy said " If a speaker measures well and sounds bad.........you're measuring the wrong things"
Regarding whether or not cables ( Speaker, interconnect, mains ) make an audible difference, here are the thoughts of someone who knows his onions. The competent credentials Dunlavy modestly refers to are the fact he invented the log period antenna whilst working for the US Air force and Cavity Backed Spiral antenna whilst working for NASA; it enabled NASA to listen to track and communicate with Gemini and Saturn space programmes. Apologies for the length of the quote but for anyone interested in the subject of cables, it makes sense to read what Dunlavy had to say; particularly in respect of well meaning, open minded listeners and the placebo effect.
To summarise for those who don't want to read the whole article...……..all competently designed cables sound just the same. Some cables, very occasionally, can and do have a sonic signature but they don't fit into the competently designed i.e neutral category. The differences these cables introduce are flaws not improvements. It may, in certain cases, be possible for certain flawed cables to rectify similar but opposite flaws elsewhere in a system. It doesn't make them better cables though...….they just might be complementary to a certain system, under a very specific set circumstances or a certain listeners preferences. These are very rare cases though...….in the vast majority of cases any perceived differences in sound are imaginary and don't hold up to any form of scrutiny.
"Subject: Cable Nonsense
Having read some of the recent comments on several of the Internet audio groups, concerning audible differences between interconnect and loudspeaker cables, I could not resist adding some thoughts about the subject as a concerned engineer possessing credible credentials.
To begin, several companies design and manufacture loudspeaker and interconnect cables which they proudly claim possess optimized electrical properties for the audiophileapplications intended. However, accurate measurements of several popularly selling cables reveal significant differences that call into question the technical goals of their designer. These differences also question the capability of the companies to perform accurate measurements of important cable performance properties. For example, any company not possessing a precision C-L-R bridge, a Vector Impedance Meter, a Network Analyzer, a precision waveform and impulse generator, wideband precision oscilloscopes, etc., probably needs to purchase them if they are truly serious about designing audio cables that provide premium performance.
The measurable properties of loudspeaker cables that are important to their performance include characteristic impedance (series inductance and parallel capacitance per unit length), loss resistance (including additional resistance due to skin-effect losses versus frequency), dielectric losses versus frequency (loss tangent, etc.), velocity-of-propagation factor, overall loss versus frequency into different impedance loads, etc.
Measurable properties of interconnect cables include all of the above, with the addition of those properties of the dielectric material that contribute to microphonic noise in the presence of ambient vibration, noise, etc. (in combination with a D.C. off-set created by a pre-amp output circuit, etc.).
While competent cable manufacturers should be aware of these measurements and the need to make them during the design of their cables, the raw truth is that most do not! Proof of this can be found in the absurd buzzard-salve, snake-oil and meaningless advertising claims found in almost all magazine ads and product literature for audiophile cables. Perhaps worse, very few of the expensive, high-tech appearing cables we have measured appear to have been designed in accordance with the well-known laws and principles taught by proper physics and engineering disciplines. (Where are the costly Government Consumer Protection people who are supposed to protect innocent members of the public by identifying and policing questionable performance claims, misleading specifications, etc.?) — Caveat Emptor!
For example, claiming that copper wire is directional, that slow-moving electrons create distortion as they haphazardly carry the signal along a wire, that cables store and release energy as signals propagate along them, that a final energy component (improperly labeled as Joules) is the measure of the tonality of cables, ad nauseum, are but a few of the non-entities used in advertisements to describe cable performance.
Another pet peeve of mine is the concept of a special configuration included with a loudspeaker cable which is advertised as being able to terminate the cable in a matter intended to deliver more accurate tonality, better imaging, lower noise, etc. The real truth is that this special configuration contains nothing more than a simple, inexpensive network intended to prevent poorly-designed amplifiers, with a too-high slew-rate (obtained at the expense of instability caused by too much inverse-feedback) from oscillating when connected to a loudspeaker through a low-loss, low-impedance cable. When this box appears at the loudspeaker-end of a cable, it seldom contains nothing more than a Zobel network, which is usually a series resistor-capacitor network, connector in parallel with the wires of the cable. If it is at the amplifier-end of the cable, it is probably either a parallel resistor-inductor network, connected in series with the cable conductors (or a simple cylindrical ferrite sleeve covering both conductors). But the proper place for such a network, if it is needed to insure amplifier stability and prevent high-frequency oscillations, is within the amplifier – not along the loudspeaker cable. Hmmm!
Having said all this, are there really any significant audible differences between most cables that can be consistently identified by experienced listeners? The answer is simple: very seldom! Those who claim otherwise do not fully grasp the power of the old Placebo-Effect – which is very alive and well among even the most well-intentioned listeners. The placebo-effect renders audible signatures easy to detect and describe – if the listener knows which cable is being heard. But, take away this knowledge during blind or double-blind listening comparisons and the differences either disappear completely or hover close to the level of random guessing. Speaking as a competent professional engineer, designer and manufacturer, nothing would please me and my company’s staff more than being able to design a cable which consistently yielded a positive score during blind listening comparisons against other cables. But it only rarely happens – if we wish to be honest!
Oh yes, we have heard of golden-eared audiophiles who claim to be able to consistently identify huge, audible differences between cables. But when these experts have visited our facility and were put to the test under carefully-controlled conditions, they invariably failed to yield a score any better than chance. For example, when led to believe that three popular cables were being compared, varying in size from a high-quality 12 AWG ZIP-CORD to a high-tech looking cable with a diameter exceeding an inch, the largest and sexiest looking cable always scored best – even though the CABLES WERE NEVER CHANGED and they listened to the ZIP Cord the entire time.
Sorry, but I do not buy the claims of those who say they can always audibly identify differences between cables, even when the comparisons are properly controlled to ensure that the identity of the cable being heard is not known by the listener. We have accomplished too many true blind comparisons with listeners possessing the right credentials, including impeccable hearing attributes, to know that real, audible differences seldom exist – if the comparisons are properly implemented to eliminate other causes such as system interactions with cables, etc.
Indeed, during these comparisons (without changing cables), some listeners were able to describe in great detail the big differences they thought they heard in bass, high-end detail, etc. (Of course, the participants were never told the NAUGHTY TRUTH, lest they become an enemy for life!)
So why does a reputable company like DAL engage in the design and manufacture of audiophile cables? The answer is simple: since significant measurable differences do exist and because well-known and understood transmission line theory defines optimum relationships between such parameters as cable impedance and the impedance of the load (loudspeaker), the capacitance of an interconnect and the input impedance of the following stage, why not design cables that at least satisfy what theory has to teach? And, since transmission line theory is universally applied, quite successfully, in the design of cables intended for TV, microwave, telephone, and other critical applications requiring peak performance, etc., why not use it in designing cables intended for critical audiophile applications? Hmmm! To say, as some do, that there are factors involved that competent engineers and scientists have yet to identify is utter nonsense and a cover-up for what should be called pure snake oil and buzzard salve – in short, pure fraud. If any cable manufacturer, writer, technician, etc. can identify such an audible design parameter that cannot be measured using available lab equipment or be described by known theory, I can guarantee a nomination for a Nobel Prize.
Anyway, I just had to share some of my favorite Hmmm’s, regarding cable myths and seemingly fraudulent claims, with audiophiles on the net who may lack the technical expertise to separate fact from fiction with regard to cable performance. I also welcome comments from those who may have other opinions or who may know of something I might have missed or misunderstood regarding cable design, theory or secret criteria used by competitors to achieve performance that cannot be measured or identified by conventional means. Lets all try to get to the bottom of this mess by open, informed and objective inquiry.
I sincerely believe the time has come for concerned audiophiles, true engineers, competent physicists, academics, mag editors, etc. to take a firm stand regarding much of this disturbing new trend in the blatantly false claims frequently found in cable advertising. If we fail to do so, reputable designers, engineers, manufacturers, magazine editors and product reviewers may find their reputation tarnished beyond repair among those of the audiophile community we are supposed to serve.
Best regards,
John Dunlavy
https://www.stereophile.com/interviews/163/index.h...
Edited by Crackie on Tuesday 4th February 10:02
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