Power cable

Discussion in 'Audio Hardware' started by Orbe, Oct 5, 2020.

  1. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    It has been a few days and I have built up enough courage to start a cable thread
    Last Thursday I got home from work and my amp was not working. It had the generic power cable that came with it, I had a friends cable to hand a TCI’s super constrictor. I put it in and the amp worked sat down started playing a cd that I was listening to the night before.
    My amp takes about three hours to get to its best. As soon as the music started playing my jaw dropped, The sound stage was much bigger faster and more defined base same with mids and treble. It still had a bit of sibilants in the treble until it warmed up but other than that it sounded better than it did the night before after three hours warm up.
    Now I never thought power cables would make such a big difference. This is not placebo affect the difference is huge I am hearing things in tracks I have never heard before.
     
  2. Swann36

    Swann36 A widower finding solace in music

    Location:
    Lincoln, UK
    Perhaps the generic power cable you had powering your amp ..although working was already compromised in some way ? wires inside broken or torn perhaps ...and so putting a different fully functioning cable on makes a difference plus of course placebo effect ......

    oh and yes cables do make a real difference ...i have Russ Andrews "300 PowerKords" for my source kit and boy did they make a difference from the standard kettle plug leads my kit (BenchMark, Cyrus, Musical Fidelity, Pathos) came with .... or is it all placebo .....if its not or if it is either way i'm happy and it seems so are you ..:wiggle:
     
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  3. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    The cable that came with it was new. I was so impressed with the improvement that I bought a TCI King constrictor today.
     
  4. Otlset

    Otlset under western skies

    Location:
    Temecula, CA
    Actually the courage to withstand the measurement-based doubters, whose basic observation about your discovery will boil down to "It's all in your head."
     
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  5. Swann36

    Swann36 A widower finding solace in music

    Location:
    Lincoln, UK
    A new cable can still be faulty in some way ....many a time in my professional life i've used brand new out of the wrappers conction cables for projectors etc that distorted the colour ....read defective cable not projector ...sadly for at least the lst 20 years everything is built to a price and quality is driven down
     
  6. Hardcore

    Hardcore Quartz Controlled

    Location:
    UK
    I recently also switched power cords, but must admit I’m a little dubious on how much they can change the sound. Maybe on a system many leagues above mine.

    I do like quality cables though.


    I bought this second hand, they don’t make this one any more and they charge a silly amount for one that looks similar.

    [​IMG]
     
  7. A least this cable has a low pass filter device on it.
    The lump that looks like its most recent meal will be blocking mains borne RFI, which will be beneficial to the sound.
     
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  8. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    I bought the amp a few months ago I was very happy with it I did not think it was lacking in any way. I always thought you could get slight improvements with better shielding. The improvements are not subtle. The new cable I have bought is the next one up to my friends one so that will be interesting to compare.
     
  9. Dr. Funk

    Dr. Funk Vintage Dust

    Location:
    Fort Worth TX
    I do not doubt your experience...my next door neighbor has spent big bucks on power cords, speaker wire, and interconnects, and swears by them. I've just never have heard a difference when comparing.
     
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  10. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    I tried my friends cardas cable with my CD player a few months ago I heard no difference at all. But this time it is huge.
     
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  11. Tullman

    Tullman Senior Member

    Location:
    Boston MA
    Be prepared to be ridiculed beyond reason. You will be labeled a day dreamer that makes believe what he hears.:-popcorn:
     
  12. Hardcore

    Hardcore Quartz Controlled

    Location:
    UK
    I opened the plug to put my own fuse in and there are three sets of wires going to each terminal, 3 live, 3 neutral and the 3 ground wrapped in another shield.

    I’m not convinced of the science behind it but they went to a bit of effort.​
     
  13. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    The cable was not mine and if there was very little to no improvement to sound quality there is no way I would have bought one four days later. When I used the cable it was only to get my amp working again not to compare it was a complete surprise to me how much improvement it made.
     
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  14. Hardcore

    Hardcore Quartz Controlled

    Location:
    UK
    Sorry Orbe I didn’t mean to sound like I was doubting your experience, what do I know.

    I definitely think that shielding comes into play with the mish mash of cables all around each other.
     
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  15. Ingenieur

    Ingenieur Forum Resident

    Amp not working
    New oem cable
    Replaced oem cable
    Amp started working
    ???
     
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  16. Glmoneydawg

    Glmoneydawg Forum Resident

    Location:
    Ontario Canada
    I feel like "constrictor" may be a poor choice for a cable name :)
     
  17. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    Funny you should say that it’s exactly what I said to my friend.
     
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  18. Orbe

    Orbe Well-Known Member Thread Starter

    Location:
    Guernsey uk
    Absolutely nothing to be sorry about. I have very little equipment out at the moment just a CD player, amp and speakers. Everything else is packed away as I am going to renovate the room soon so not to many cables.
     
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  19. Boltman92124

    Boltman92124 Fish tacos.

    Location:
    San Diego
    I swapped in a Audience Forte PC for the stock cord on my admittedly cheap Parasound New Classic amp. I really don't think it was any kind of game changer. Maybe a more full bodied sound. But it is a solid piece of kit with much nicer connectors and looks nice so no regrets.
     
  20. Ingenieur

    Ingenieur Forum Resident

    I'm a skeptic based on education MSEE and 30+ years of power/signal experience plus playing with hifi for 45 years. But I am willing to be educated by a technical explanation.
    What parameter(s) would change to cause the difference?

    1 The Z of the cable is perhaps 10% of the total circuit: utility transformer, service drop, branch ckt to receptacle, etc.

    2 The cable conveys no signal, only 60 Hz power, which is somewhat filtered thru the amps xfmr's L and further by the power supply caps.
    The cable does not filter any line noise, and even if it did the difference on the DC rail would be moot.

    3 shielding constrains the cable field, external stray EM fields. Both are very small and easily mitigated by a few inches of separation at 120 vac.

    The power for the music comes from the caps, the 120 charges the caps and that rate is dependent on the size of the C and total circuit R, which the cord is 10% of at most.

    time constant tc = R C
    t = time
    Vc = Vs(1 - e ^-(t/RC))
    Vc = Cap V
    Vs= supply V (Rectified amp xfmr sec V)
    1 tc 63.21% x Vs
    2 tc 87.47%
    3 tc 95.02%
    4 tc 98.17%

    if we assume total Vdrop pole to amp is 5% or 6 V at 20 A that is 6/20 = 0.3 Ohm
    12' #12 ~ 0.02 Ohm or 7% of the total

    assume a 100 W amp with 40000 uF
    tc with 0.3 Ohm ~ 0.0120
    98.17% in 48 mSec

    assume new cable 0.01, 1/2 of old
    tc with 0.29 Ohm ~ 0.0116
    98.17% in 46.4 mSec
    ie, old cable is 97.9% vs the new 98.17% for the same time of 46.4 mSec

    This assumes a fully loaded circuit and 100% power output.
     
  21. Ingenieur

    Ingenieur Forum Resident

    As far as the cables reactive components C and L, they only affect phase angle (angular delta between V and I) in this case it's the power factor. Pretty much determined by the utility service and all connected loads so cable L and C have little or no impact (the amp power supply Caps are a different story, they swap reactive power with the speaker coil L).
     
    Last edited: Oct 5, 2020
  22. MondoFanM

    MondoFanM Member from ATX

    Location:
    Austin
    You can live through me and see the abuse I took over on Reddit LOL

    Who does power cables? : audiophile
     
  23. regore beltomes

    regore beltomes Forum Resident

    Location:
    Helenville, WI
    When I was younger I could hear ultrasonic. No one would believe me either !
     
  24. elvisizer

    elvisizer Forum Resident

    Location:
    San Jose
    at least it's not an ethernet cable/switch thread.
    I know less about power cables than data cables . . . so I wonder about them as well. Just not enough to spend money on them yet!

    yeah, me too- the security systems at the local mall were REALLY loud!
     
  25. jea48

    jea48 Forum Resident

    Location:
    Midwest, USA
    Quote from Link below. Note year 2000.

    "
    The usual scientific explanation
    209.215.72.213

    REPOST
    AC Power Cord Effects

    So, how in the world can a power cord make any difference, if it is properly rated for the current draw, and is UL listed?
    Like many questions about audio systems, this one seems very logical and reasonable. Just use Ohm's Law to calculate the current draw, and viola, we have the voltage drop, and we have the cold hard facts, Yes?

    No.

    Like many overly simplistic answers, this one does not take into account all the facts. Let's look at a hypothetical power amp to start. Lets say it is a moderately high power design, and is rated to draw about 8 amps from the wall at full rated power. That's about 960 watts from the wall. We won't even get into side issues of switching power supplies, which play total havoc with the simple Ohm's Law approach, we will stick to linear power supplies.

    So if the AC cord is UL listed for 10 amps, it is likely an 18 gauge cord. Many 18 gauge power cords are rated for 10 amps of current. How is this rating determined? By how hot the cord gets while carrying the rated current, NOT how much voltage drop there is.

    In our hypothetical amplifier, the RMS voltage drop in the 6 foot cord would be approx. 1/3 of a volt according to Ohm's Law. This does not take into account the wall outlet contact, or the IEC connectors if present, nor does it take into account any other factors, just the resistance of the 18 gauge wires in the AC cord.

    On the face of it, this seems quite harmless. How could a third of a volt make any difference? Well, because the voltage drop is NOT 1/3 of a volt! Has Ohm's Law been repealed? Are engineers all insane?

    No, just an overly simplified analysis that failed to take into account ALL the factors. So what could possibly make that much difference. Well, for one, it would help to know that linear power supplies refresh their DC reservior from the AC line in bursts of current, current peaks that are in time with the peaks of the AC line. That is when the filter capacitors are refilled, when the AC line voltage its it's peak value, and the output from the secondary reaches a level above that which the PS capacitors have been drained to. Instead of a nice steady drain of 8 amps, we have current peaks that
    last only for a brief moment, and the 8 amps is an RMS amount.

    What this means is that because the current is being drawn only for a fraction of the AC voltage cycle, or for about 1 thousandth of a second (one half cycle lasts for 0.0083 seconds). The peak currents can easily reach ten times the RMS value. What is the voltage drop for 80 amps? At this point, the resistance of the AC plug contacts, and even the bond inside the cord between the plugs and the internal wires become a significant factor. It is not hard for the voltage drop to reach 5 volts or more. The AC line peaks never reach the full value, because the line cord has lost some of it.
    Power amps depend on receiving the full measure of AC line for their full rated power, so such a drop will reduce the actual output power in a seemingly disproportionate amount. A 200 W amp may be reduced to 170 watts before clipping.

    The above (still simplified) analysis assumes a steady signal, and a steady current draw. Musaical dynamics make it a much less consistent thing, and the dynamic demands will cause dynamic perturbations.

    This is not the only effect on the power amp. These current peaks can easily cause AC line distortion, and the heavy current draw can generate harmonics on the line, the hash from the rectifier diodes can increase, a whole series of events occurs that are not immediately obvious just by thinking of the amp as a simple resistor and using Ohm's law.

    Most house wiring is either 12 gauge or 14 gauge, while many OEM cords are 18 or at best, 16 gauge. Most OEM cords do not have shielding or any provision for reducing radiated EM fields, do not have premium AC outlet plugs or premium IEC plugs for better electrical contact at these junctions.

    So what happens with a bigger power cord? Replace that 18 gauge cord with a 14 gauge cord, and the voltage drop will go down by a factor of about 2 and a half.

    Include shielding in that cord, and the possibility of radiated EMI/RFI goes down compared to an unshielded cord.
    Shielding and radiated EM fields might not seem relevant since the house wiring has neither advantage. However, the house wiring is not laying right next to the other component's AC line cords, or right next to the line level or speaker interconnects. Reduced levels of induced RFI and radiated EMI/hum fields would not hurt SOTA sound reproduction.

    Since the AC power cord is usually laying right in there with all the other AC cords, and probably the speaker cables, and the interconnects (some people even bundle them all together for neatness, OUCH!), it is quite possible that a premium AC cord will help reduce interference in the system, and raise the amount of power available before clipping,
    and smooth any AC line distortions, etc.

    This is all without even going into secondary effects, or other more esoteric aspects. Just a more nearly correct way of applying Ohm's Law to the real situation. Add in ferrite filters, built-in filter components, shielding effects, and the esoteric aspects, and it should be obvious that AC cords are not at all simple, nor are they a no-brainer.

    There is the issue of resonant situations. Certain power cords and power supply transformer primaries might tend to resonate at RF or high frequencies. This resonance might make RFI/EMI problems worse, changing to a different cord will change the resonant frequency, and change the RFI/EMI effects.

    The plugs are not a trivial issue either, and may be more responsible for sonic improvements than the other factors.
    Hubbel and other premium plugs and sockets will increase contact area and pressure, reducing contact resistance and other contact related problems. It has been claimed that poor AC plug contact can cause micro-arcing, with it's attendant hash being injected directly into the audio component.

    It is not as simple as just simple wire resistance. The connection at each end of the cord adds resistance, the wall outlet socket adds resistance, etc.
    For the raw wire, round trip:
    12 gauge, approx. 6 feet = 0.0206 ohms
    14 gauge, approx. 6 feet = 0.0328 ohms
    standard AC power cord
    18 gauge, approx. 6 feet = 0.0830 ohms

    Measuring real AC power cords, I get around 0.128 ohms for an IEC 18 gauge power cord, and about 0.022 ohms for a 12 gauge IEC cord, not including the AC wall socket connection.

    Why is the 18 gauge resistance so much higher than just the wire resistance? Ever tear one of those cheap cords apart? Poorly crimped or barely soldered connections are responsible for the bulk of the extra resistance.

    Preamps and CD players all have their special requirements: CD players require shielding to help keep the digital hash that back-feeds from the circuitry out of the rest of the equipment, preamps need a nice steady voltage for minimum noise, and freedom from RFI, etc.

    Fancy AC power cord geometries might also reduce the inductance of the 6-8 feet of line cord, raising the available voltages. but this would be limited to the ratio between the length of the power cord vs. the wall run. Such geometries often reduce the radiated energy, and aid shielding of the cord.

    Some power cords might have a built-in filtering action, like the water jacketed ones, that have the conductors and insulation surrounded by a conductive fluid. This fluid might short out and reduce/damp any EM fields the cord would conduct to the component besides the 60 Hz AC power signal.

    It also helps to keep in mind that we are not supplying a Sears rack system, that any system which aspires toward the SOTA is going to be more sensitive to minute effects and minute improvements. How much does a big fat shielded power cord help things? Probably about as much as upgrading from an OEM interconnect or zip cord speaker cable to
    some decent aftermarket cables, some systems are more sensitive to AC cords, some are less sensitive to cords.

    As always, the bottom line is: you have to listen for yourself, and see if their is any benefit for you, on your system, with your listening habits.

    Do AC cords have the potential to influence high end sound? Yes. Does anyone who believes this also believe that high end cord costs are justified? No.

    In my DIY AC Cord note, I recommend an $11 shielded heavy duty Belden (now Volex) cord, not a thousand dollar high end cord.

    See my DIY AC cord note at:
    http://members.nbci.com/Jon_Risch/ac-cords.htm

    Some of the cord/cable manufacturers get carried away with using only the very finest materials and assembly techniques, carrying over the technology and costs from their high end audio interconnects and speaker cables.

    Is this necessary? I don't know, I will not discount it out of hand. Does it make the cords cost a lot? Yes.

    Does this make them dishonest or imply that they are deliberately trying bilk the customer? Not at all.

    Jon Risch
    "
    The usual scientific explanation - Jon Risch - Cable Asylum

    Thread:
    gah, please tell me I didn't just hear this. AC cords! - pcanis - Cable Asylum

    .
     
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