Question for Atma-sphere, will expensive power cables improve your amplifiers?

@helomech +1 "Use caution when shopping for “audiophile” cables and cords. Some of them are poorly designed and actually inferior to cheapo manufacturer-supplied cords/cables."

@jfrmusic +1 on findings "I have tried several upgrade power cords on my Accuphase P4600 amplifier. None sounded better than the stock Accuphase supplies. Upgrded cords seem to darken the sound, reduce openness and airiness. Accuphase documentation is quite emphatic about only using their cord."

-hopefully your Accuphase IEC receptacle's  contacts didn’t get significant damage, often random aftermarket IEC plugs, leave heavy marks on contacts, and damage contact surface.

Use caution when shopping for “audiophile” cables and cords. Some of them are poorly designed and actually inferior to cheapo manufacturer-supplied cords/cables.

I have tried several upgrade power cords on my Accuphase P4600 amplifier. None sounded better than the stock Accuphase supplies. Upgrded cords seem to darken the sound, reduce openness and airiness.  Accuphase documentation is quite emphatic about only using their cord. 

This info on Neotech's NEP 3200G includes a good image of the construction showing the type of solid core construction that @jea48 is referring to.  Scroll through the pictures in this next link to see a similar image of the construction of their flagship Grand Power Cable, which uses rectangular conductors.

Do power cable have to have UL certification? Just curious

No law that I know of.

As for NEC...  NEC code stops at the outlet cover plate of the wall outlet.

I am pretty sure there is audio equipment made and sold in the US that is not Listed.

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Do power cable have to have UL certification? Just curious

@atmasphere

@jea48 Just so you know, solid core wire for a power cord is illegal and for a good reason! On that account, I’m pretty sure your statement above isn’t correct.

Yes, a single solid core #14awg or a single solid core #12awg wire, or a #10awg solid core wire would not meet electrical safety code for a power cord.

Several smaller gauge solid core wires individually insulated grouped in parallel together for the Hot and neural conductors, for use in a power cord, will/does meet NRTL safety testing.

AudioQuest was making power cords back in the 1980s paralleling multiple small gauge solid core insulated wires together to make a combined equivalent single gauge conductor for the Hot and neutral conductors.

I sill have a couple of non shielded AudioQuest AC-12 power cords. It’s equal to a 12awg X 3 cable using four separate solid core 18awg cu OFHC insulated wires conductors for the Hot conductor and four for the neutral conductor. A 12awg stranded green insulated wire is used for the EGC, Equipment Grounding Conductor. The conductors were assembled together in what AQ called a "Hyperlitz design".

The individually insulated eight #18awg solid core wire conductors were placed surrounding the #12awg stranded insulated EGC. That design had to be the EE in Bill Lowe. It cancels out the EM fields from the hot and neutral current carrying conductors from inducing a voltage onto the EGC.

Fast forward to today high end audiophile power cords manufacturers are still using AQ’s use of using individually insulated solid core wire conductors. Though the wire gauge size of insulated solid wire varies in the design. I’ve read where some will have a mix of 18awg and smaller solid core individually insulated wires, and some add Lintz (insulation) wire in the mix.

The geometry construction of the power cord has greatly changed as well since the 1980s. And most of the building of the cable is done by had, from my understanding.

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Very few audiophile cables made today use stranded wire.

@jea48 Just so you know, solid core wire for a power cord is illegal and for a good reason! On that account, I'm pretty sure your statement above isn't correct.

Power cords are (mostly) three runs of stranded copper wire with PVC insulation, twisted together (sometimes with filler material for damping), and encased in a PVC jacket. The main variables that affect power transmission are the wire gauge, shielding (or not), and connectors.

True for the majority of OEM mass produced power cords.

For power amplifiers they may sound fine. For digital equipment not so much.

Most audiophile power cords are not built using three stranded wire conductors.

Solid vs stranded conductors will make a difference. Very few audiophile cables made today use stranded wire.

Method of conductor and cable geometry used can change the sound heard from an audio system.

Shielding can make a difference. Sometimes for the worse in sound. Depends on how it’s implemented.

Type of the wire used, therein the Hot and neutral current carrying conductors, can make a difference.

Agree the connectors used, male plug and female IEC connectors, can make a difference.

Wouldn’t that be a case for keeping component power cords as short as possible?

For OEM power probably. Depends on the wire gauge used. For an audiophile power cord not really. 5ft - 6ft seems to be pretty common.

@mitch2 Yes! You also want good solid connections at either end so they don’t heat; heat means a Voltage loss.

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If you want an inexpensive means of building a power cord, use the kind of AC power cord used by an electric dryer or stove. Put a set of decent connectors on either end so you don’t get the connections heating up (which represents a Voltage drop) and you’ll have a very competent power cord.

Of course you have to watch things like which side is hot and which side is neutral so an electrician might have to be the one to do the work for you.

Any tube amp has in addition to the high Voltage power supplies, also a filament supply which is usually not regulated. So when there’s a Voltage drop across the power cord, not only is the B+ Voltage on the power tubes a little lower but the tube is less efficient since the cathode (heated by the filaments) is running at a lower temperature since the filaments are running cooler.

Put another way this means that tube amps are generally more sensitive to power cords than solid state amps are. But solid state amps can be affected too. The more regulation that is used (for example, in our MP-1 preamp where all the power supplies are tightly regulated) the less sensitivity you’ll have to the power cord.

One variable I've not mentioned yet: In a power supply there are rectifiers that convert AC from the power transformer to DC and filter capacitors that are charged by that DC. But the rectifiers only conduct when the output of the power transformer is higher than the Voltage on the other side of the rectifier. The filter capacitors retain a charge from one iteration of the AC power waveform to the next, so the only time the rectifiers conduct is at the peak of the AC waveform. At that time, the current has to move swiftly to charge the cap and so there is a current spike when the AC Voltage is at the peak. This might only be for a few milliseconds. If the power cord has troubles with what is essentially a higher frequency (due to the steepness of the current spike itself) it could limit the charging time.

That could result in a lower power supply Voltage with more noise. Some power cords are better at this than others.

That is why you can hear differences between power cords. Anyone that says otherwise clearly has not measured the effect they can have on equipment. IOW what I’ve said here can be backed up with measurements.

Power cords are (mostly) three runs of stranded copper wire with PVC insulation, twisted together (sometimes with filler material for damping), and encased in a PVC jacket.  The main variables that affect power transmission are the wire gauge, shielding (or not), and connectors.  It is not that expensive for an equipment manufacturer to include a sufficiently sized and shielded power cable that will facilitate pretty much the full performance level of their equipment.  That should be the baseline.

@atmasphere -

"Usually the house wiring has far less Voltage drop than the power cord. This has a lot to do with the fact that wiring in the wall is solid core." 

Wouldn't that be a case for keeping component power cords as short as possible?

I have MA-1s and noticed some improvement with aftermarket power cords. Very expensive and borrowed. Didnt like the high end Shunyata power conditioner on these amps so they go right into my wall.

I agree the cable companies "loan" the cables...but if Pass thought their own cords sounded better, can’t imagine not using them in their voicing room and at shows...I read where Nelson Pass was loaned a pair of Kimber speakers cables, and quite liked them, until he learned they were $54.000 a pair...in their older manuals Pass simply said your cables shouldn’t cost more than your components...it's a fun company...

If every wired audio component forms a "link in a chain", how can replacing just one "link" in the chain have an appreciable effect on the whole chain?

Is the goal of substituting one less-effective link with a more-effective link to improve the conducted "signal" from the improved link onward, and how does that work?

(i believe atmasphere partially answered that question above, but I'm perhaps too dense to comprehend the explanation)

While rumor often has it that Pass doesn’t believe in upgrade power cords and cables, rumor and visitors also report that Pass uses expensive Silent Source Cables in their listening room and at shows...my Pass mono blocks came with good power cords, but I prefer my Cerious cords...

Many times, I believe, cable, audio furniture/accessory companies may help pay some of the "booth" costs if their products are featured. That is what I'm guessing. 

@atmasphere Thanks for clarifying

One question, do you mean voltage drops from the "wall" or within the amplifier itself due to volume adjustment.

@aberyclark I’m referring to Voltage drops from the wall. In the case of our class D the volume control will affect the Voltage drop.

Usually the house wiring has far less Voltage drop than the power cord. This has a lot to do with the fact that wiring in the wall is solid core. Such wire is not legal for power cords. So if anyone is wondering about the ’last 6 feet’ that’s the answer.

The cables shown in the pics carry DC power, but how is DC vs AC apples to oranges as far as the quality of the cables is concerned?

The rectified DC is filtered through electrolytic caps to smooth out the full wave DC ripples and then in many cases is run through DC regulators.

The AC power cord plugs into a wall outlet. Hard tell what its about to receive. The good, the bad, and the ugly...

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@oberoniaomnia, aren’t both cables in the photos above DC power from the power supply to the receiving equipment. Wouldn’t that be comparing apples to oranges.

@jea48

The cables shown in the pics carry DC power, but how is DC vs AC apples to oranges as far as the quality of the cables is concerned?

(If I misunderstood something I apologize)

While rumor often has it that Pass doesn’t believe in upgrade power cords and cables, rumor and visitors also report that Pass uses expensive Silent Source Cables in their listening room and at shows...my Pass mono blocks came with good power cords, but I prefer my Cerious cords...

@atmasphere wrote
Because the customer has to be able to plug it in right away. Even though they may never use the stock cord, if you were a manufacturer and didn't include it you'd hear about it right away.

Then why don’t amplifier manufactures include speaker cables?  An amp is used to drive a speaker…..correct?   Obviously, I’m being sarcastic.

I’m 58 years old. Back in the old Stereo Reviews I read as a kid, I do not remember emphasis on cables like we have today. I’m sure there were others, however, the first "cable" manufacturer of any big advertising clout I remember was Monster. For myself, back then, cabling was easy. Most power cords were built in (on my components at least). I either used the cables that came with the unit or just went to Radio Shack and purchased their run of the mill interconnects. Of course, for speakers, I pulled the length I needed from the large spools at RS.

@inna +1 "Accuphase stock cords are not too bad”, indeed! Accuphase cables are very good electrically speaking! More expensive cable upgrades cannot not change sound anyhow, assuming no other issues like RFI nose etc. In analog design PC is at bottom of design pareto chart, which specifies impact of every chain part to final result.

+1 "The most important cable in the system is tonearm cable not power cords” yep, in analog sound system phono cable and tonearm wiring, on top of cartridge and tonearm itself, are very important parts! 

@oberoniaomnia there are quite a few high end cable companies that make custom cables for two box units. They may not advertise them, but they are available upon request. Just look up high end audio umbilical cables.

@oberoniaomnia, aren't both cables in the photos above DC power from the power supply to the receiving equipment. Wouldn't that be comparing apples to oranges.

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@invalid "bus bars" sound like something *inside* one chassis. I google image searched Krell bus bar, and I only get single chassis items. I doubt that on a power amp there would be bare metal external linkers like speaker jumpers.

I am talking about 2 box set ups with connecting cable, and about so-called "upgrades" to those power connecting cables. See below on the Woo WA6

And here the Holoaudio May with power connection cable.

@oberoniaomnia my Krell amp is over 30 years old, it has beryllium copper buss bars from power supply to signal circuits, so you haven’t given anybody any new ideas.

@alexatpos Myy Luxman 595 came with a great power cable. I switched in A ZU Event cable and no difference at all. HOWEVER, The ZU cable was a smidge better with my old Nuforce ST120 (class a/b) vs the stock cord. Then again the NuForce was a $600 amp vs a $13,000 integrated.

I heard that Gryphon and Accuphase stock cords are not too bad. And also Boulder, I think.

The most important cable in the system is tonearm cable not power cords.

@aberyclark I 've had Krell Evo 302 with its stock 20A power cable, tried few others, the one from Krell was better and quite enough, imho. Burmester gives power cords with is components (which are also possible to buy separated) and again, they are hard to beat before Nordost Valhalla level. Needless to say, I keep Burmester power cords on my Burmester amp and player.

@atmasphere Thanks for your response. What you said makes a lot of sense. One question, do you mean voltage drops from the "wall" or within the amplifier itself due to volume adjustment. Excuse my electronic engineering ignorance. If from the wall, would a voltage regulator/conditioner, etc...help with such?

I do agree if your amps were delivered without power cables, you would hear about it. I've read forums where somebody gives an impression about a device but points out that the remote did not include batteries. So you can only imagine if the person could not plug the thing in LOL

Manufacturers don't want to get into the middle of a p**sing war. 

Buyers can use whatever cable they choose, just as they can install any fuse they want.

From my experience, power cables can exert a noticeable change in sound reproduction. AQ is my go to brand.

Bob 

@devinplombier interesting possibility re legal requirement for some power cable. There would still be the possibility for basic and upgraded cable. Particularly those that according to electronics manufacturer have the best "synergy".

Someone else mentioned that the reason is that electronics manufacturers do not make their own cables. They do not make their own capacitors ... either, so that notion does not apply either.

Re simple interconnects, the ones I have on my Woo WA6 SE and also on the Holoaudio May are something quite different. My point stands that I have not seen any discussion on upgraded power connectors between power supply and signal processing box. Wall socket to power receptacle, yes. Signal interconnects of every description, yes. Power connection between power supply and signal box, no. I hope I did not give anybody any ideas, yikes!

A better question may be "why do the manufacturers of a $7,000 amplifier even bother to include a power cable", given that it will be immediately replaced?

@tony1954 Because the customer has to be able to plug it in right away. Even though they may never use the stock cord, if you were a manufacturer and didn't include it you'd hear about it right away.

A better question may be "why do the manufacturers of a $7,000 amplifier even bother to include a power cable", given that it will be immediately replaced?

yes ! cables  make  huge  difference. i  have  parasound a21+  ive  replaced standard power  cord  with Nordost, "heimdal"  power  cord. also  use  Nordost rca "heimdal"  between naim pre amp,  and  power amp  , best  thing  is  to  ask your local  dealer  for  an in home  ''try  before  you  buy '' .  most  dealers  will accommodate  you,   good  luck 

"Question for Atma-sphere, will expensive power cables improve your amplifiers?"

@aberyclark Power cords affect the sound of an amp due to Voltage drop across the power cord. Due to the power draw of our tube amp power cords can affect them quite a lot but not so much for our class D where the power draw at idle is insignificant. If you were pushing that amp hard all the time then the power cord would make a difference in theory; so far we've no feedback on that at all.

If you’re trying to determine “value”, you’ll never get there.

This high-end audio hobby is a small niche market. To cover time, effort, costs included R&D, markups are required.

In this copycat world, cable manufacturers do not give away their secret sauce to their competitors. We consumers are left in the dark also.

So all we have is understanding up to a point, then must evaluate increased sonics at a price - an often fuzzy subjective process.

Finally, seems most have benefited from upgrading their power cables, at least to the next level costing <1k.  Maybe try one on loan for free, or buy used and if unsatisfactory sell it afterwards.  Be very cautious to avoid buying “fake” used cables. 

Why do equipment manufacturers provide a power cord at all? Leave it up to the customer to decide what kind of cord he/she wants. 

@oberoniaomnia 

My unverified guess is that if the equipment is certified, a power cord must be included.

I have yet to hear about cords connecting separate power supply chassis to electronics units to have upgraded cables.

To your point, the power cable between my Krell preamp and power supply is a DB9 to DB9 cable that costs maybe $5. Those are signal cables once known as RS-232 or VGA. They have 26 or 28AVG conductors so they were never designed for power applications, especially the not-insubstantial amounts the Krell PS puts out. 

Aberyclark sorry I mistyped your name. Lak is correct

@aberyclark I just wanted to point out the 2 different definitions of a "quality power cable" that might require 2 different answers to your question.

Abbeyclark buy a used atmasphere amp experiment with different power cables from usedcable.com. If you are not happy resell them. Thats what I will do.

Manufacturers don’t wanna have anything to do with cables!

I don’t understand why you guys don’t understand this. It’s a noob thing to say.

they just give you the cheapest power cable just to prove to the dealer or distributor that it will turn on. That’s the only reason for that cable is not to be listened to. It’s just a function test.

Best to ask Atmasphere owners about their experience. Right? As a past owner it is easy for me to say yes power cords made a nice improvement.  Not only on Atmasphere gear, but on most all gear I have owned.  Power cords are the most important cabling in your system.  Always start there in terms of relative importance. However, it sounds like the OP has already made up his mind on this topic per his posts here.  I do understand some folks may not hear or appreciate the difference an aftermarket power cord can make. Many reasons from room to gear to ears.  

Best to ask Atmasphere owners about their experience. Right? As a past owner it is easy for me to say yes power cords make a nice improvement.  Not only on Atmasphere gear, but on most all gear I have owned.  Power cords are the most important cabling in your system.  Always start there in terms of relative importance. However, it sounds like the OP has already made up his mind on this topic per his posts here.  I do understand some folks may not hear or appreciate the difference an aftermarket power cord can make. Many reasons from room to gear to ears.  

@aberyclark  - Your question is answered thanks to @jea48 

Read page 8 ... The power cord can have audible effects! A good cable is recommended.

I would switch the question around: Why do equipment manufacturers provide a power cord at all? Leave it up to the customer to decide what kind of cord he/she wants. Many TTs are sold without cartridge, and are unusable without one. Or for tube equipment one has frequently options about tube sets.

I guess the above premise also provides the implicit answer: Like Nelson said, above basic requirement, it does not matter for sound in the vast majority of situations. 

I find it also interesting that the standardized power cords are upgrade worthy. However, I have yet to hear about cords connecting separate power supply chassis to electronics units to have upgraded cables. Just some idle musings ...