How to A/B Test Power Cables & Interconnects?


Looking for some advice. Here is the situation:

  • I am building out a new system (dCS Bartok > Parasound JC 2 BP > Parasound JC 5 > Floorstanding Speakers)
  • Equipment is on-hand. I am in the process of re-wiring the A/C circuit with two matching, 10awg home-runs (one for power Amp, one for sources)
  • I have the opportunity to try some high-end power cables and interconnects
  • I will invest in the cables if there is a discernible difference. I am somewhat skeptical.
  • I am trying to come up with a test protocol to determine what these higher end cables do. Everyone advises that I do A/B testing will listening to music. Of course I will do this.


My question:

Is there some more objective way to A/B test power cords and interconnects? I prefer to do this by listening,...not using lab equipment. How can I A/B measure system "blackness" or noise level?


Any advice appreciated. Thanks in advance.


128x128temporal_dissident
Big power amps with linear supplies can draw peak currents off the AC line in the 10's of amps. Depending on the gauge of your run, even with 12 awg, that can lead to significant voltage drop and essentially modulates your AC line which leads to distortion products that are a function of 1x line frequency, 2x line frequency, and the frequency of the music. It all depends on how sensitive your equipment is to noise on the AC lines.


The problem will be which "pro". Both electricians and inspectors can run into knowledge gaps when you are doing something out of the ordinary. I have had to deal with that a few times.

Whether you can slide by a single ground wire would come down to the size of the breakers. Typically the ground wire must be equal to the size of the conductors, and since you have 2x conductors, you would need 2x ground wires of equal gauge or the breakers rated for less current than a single run of the ground wire. Better and safer to connect both.

builder3
206 posts
10-22-2019 9:07pm
Why not just have one circuit? There’s no load to speak of. A single run of 12 wire and whatever outlets and box you care to use should be more than adequate. 
On a separate note (and run this by a real electrician), I’m wondering if there’s any reason you’d be prohibited from having the two separate circuits, but only use one of the grounds for both. Leave the second ground unused in the back of the box. May be reasonable, may not be, talk to a pro.

Why not just have one circuit? There’s no load to speak of. A single run of 12 wire and whatever outlets and box you care to use should be more than adequate.
On a separate note (and run this by a real electrician), I’m wondering if there’s any reason you’d be prohibited from having the two separate circuits, but only use one of the grounds for both. Leave the second ground unused in the back of the box. May be reasonable, may not be, talk to a pro.
I am not an electrician either, though was once fairly handy with the electrical code, but that was a while ago. Just went down to my panel, as expected, I have a dual single pole breaker that both trip at the same time (not a common 2-pole), however, perusing HD website and I can't find this style any more, so that tells me that maybe they don't make them any more?

Perusing the web, it does not appear that doing this is verboten, but, like my installation, you would (for residential) need a breaker that disables the circuit at the same time. That could be tough with a breaker panel, easy with a ganged breaker in a box. 

The easiest thing, that would not confuse inspectors, would be to have two outlets close together and just tie a ground between the two.


builder3
203 posts
10-22-2019 6:26pm
robert, first, I’m not an electrician, so take anything I say with a grain of salt. That being said, I have been in residential construction for 30 years. I’m in the Pacific NW. I’ve never seen an electrician here use a metal box in a home without good reason. Something heavy, like a ceiling fan, or remodel work in an older home. I wouldn’t think audio AC cables would rise to that level, given a quality box like a Pass & Seymour, etc.I wouldn’t run a ground like you describe. An electrician may or may not, I’m not sure. Generally, from my limited understanding, it’s not advisable to just bond grounds together at random. I’d have two separate circuits, or only one. 

robert, first, I’m not an electrician, so take anything I say with a grain of salt. That being said, I have been in residential construction for 30 years. I’m in the Pacific NW. I’ve never seen an electrician here use a metal box in a home without good reason. Something heavy, like a ceiling fan, or remodel work in an older home. I wouldn’t think audio AC cables would rise to that level, given a quality box like a Pass & Seymour, etc.I wouldn’t run a ground like you describe. An electrician may or may not, I’m not sure. Generally, from my limited understanding, it’s not advisable to just bond grounds together at random. I’d have two separate circuits, or only one.

P.S. My panel has two bars, one on the right, one on the left. Grounds and neutrals connected to the nearest spot. Both bars are connected behind the main breaker I believe, and then to the ground lug.


By code, they (grounds) have to be all connected at the panel to a single bus-bar do they not?

Perhaps obsolete, and I wonder if regional, but I am still seeing more metal boxes even in new construction, in north east U.S. and Canada, but pretty much all plastic with integrated vapor barrier for the exterior. Are we talking the same thing? i.e. ... https://www.homedepot.com/p/2-Gang-Drawn-Device-Switch-Box-with-Bracket-685SP/100154820

Sounds like you know this well. I would be interested in your insights ... and how it relates to mechanical as per the next paragraph.

While metal boxes have higher potential for "liability", if they are improperly grounded and a live wire touches the box, and a person touched a screw that attached to the outlet cover that attached to the box, then yes they could get a shock. (Or you cut the romex on the sharp metal). On the other hand, with people hanging literally pounds of audiophile AC cables off them, and multiples at that, the significantly higher rigidity of metal could balance out any benefits of plastic.

That said, for the DIYer, plastic can be safer (and easier), and since the gauge used was 10, it should be easy to just run each ground to the separate receptacles (in the same j-box), and then run a ground wire between each receptacle so the grounds are at the same potential.





If you have a modern breaker panel in the U.S., all of your grounds are joined at a single bus bar in the panel, and then go to ground. If you have dedicated circuit(s) going directly to the panel, you shouldn't have any metal electric boxes for outlets. Or anything else. They're obsolete, and a liability in a modern electrical layout, in all but a few exceptions.
That part is easy. Just bring your two home runs into the same junction box connecting the ground from each to the J-box metal, and then to each receptacle. 
OK. How do I address this? What is involved in getting both circuits on a common ground? (Assuming that is the solution.)
If you have separate junction boxes for the receptacles, then I would assume the grounds are different (at the receptacle). 

All equipment has either intentional capacitive connections and/or parasitic connections from internal circuitry to case-ground. Without your equipment connected, except for the AC, those grounds connect back at your electrical box as you have it wired. As they operate, they inject signal into the ground, which is now separated by two long wires which means that ground on one set of equipment is going to be different from ground on another set of equipment. That ground difference is injected into the connections between your equipment.

As you are using balanced connections, fortunately most of that noise is going to be eliminated, but keep in mind, that noise tends to "pump" with the signal, so your floor with no signal may be really quiet, but that does not mean there are no noise issues.

If all the equipment has the same local ground, then the ground noise is only injected over the lengths of the power cords, not the length of the home-runs (2x) plus the power cords. As the injected current will be the same in both cases, the longer resistance of the added 2x home runs will make for a bigger noise signal voltage.


Two homeruns are identical length romex, and on same phase. Seperate junction boxes. Grounds go to same panel, but not sure about them being "tied together." My thought was one circuit for power amp and the other circuit for all other components. 

XLR from DAC and Phonostage into PreAmp, and XLR from Pre to Power Amp.

I have not tested it for noise yet,....


If it makes you happy, and takes away worry, it is money well spent. When you spend that kind of money on a system, you want it to look nice as well. 

Are your receptacles in separate junction boxes each with their own run back to the breaker box or are they in the same junction box with the grounds tied together. Having multiple grounds is generally a recipe for noise, but if you are using XLR, it will likely never come into play.


"I also did two home-run circuits, 10awg romex, matching phase, Oyaide receptacles. "
Settle down, people. We aren't curing cancer or defending the homeland. It's a hobby, and it lends itself to a lot of subjective opinion (wine?). 

robertcan I appreciate your perspective about $$$ spent on room treatments. I take your point. 

My OP was never about A/B testing a  bunch of expensive cables and comparing "color" of each. The essence of the question was this: if you are investing $50k+ in a system, are you cutting off your nose in spite of your face to use the power cords that were included in the box? Is it a no-brainer to spend 5% of budget to upgrade cords and cables. 

My primary concern was always noise floor, not "color."

Conclusion (for me anyway):
Many "answers" have been proposed. The one I am choosing to take away: Not necessarily. There are other areas to spend with potentially higher ROI. Room treatments certainly being top of the list. (My room is FAR from perfect.) I choose to invest in cables and interconnects from the "Plus" and "MusicLink" lines from Transparent Cable. These are "lower end" from Transparent, but still a stretch for my budget. I also did two home-run circuits, 10awg romex, matching phase, Oyaide receptacles.

Regarding power and cabling, I've done more than some and less than others. Money wasted? Maybe. Honestly, I won't do a ton of A/B testing so I may never know. I see it as an investment to eliminate a theoretical constraint on my system. I sleep well, knowing that I have not constructed my building (stereo system) on a foundation of sand (poor power). 

Speakers deliver tomorrow. I am shifting my attention to the music.

Thanks all for input.  


Do you have anything to add to this conversation, or are you just harassing members on this forum again?

My post clearly discusses how to A/B (i.e. get someone to do it for you so you don't know), then it illustrates how bias enters into the results of so called professional reviewers.


clearthink
914 posts
10-22-2019 1:17am

roberttcan
"I think the best way to A/B power cables is to first ask yourself, have I spent at least $3,000 - $5,000 on acoustic room treatments, and I would even go to $10,000."

The cost or expense of room treatments is unrelated in form of function to A/B'ing power cables if you cannot see that truth you are more confused than even I thought.

Post removed 

roberttcan
"
I think the best way to A/B power cables is to first ask yourself, have I spent at least $3,000 - $5,000 on acoustic room treatments, and I would even go to $10,000."

The cost or expense of room treatments is unrelated in form of function to A/B'ing power cables if you cannot see that truth you are more confused than even I thought.
I think the "aholer" in this thread is painfully obvious.


millercarbon
1,805 posts
10-01-2019 9:34pm
Wouldn't it be a whole lot more honest if people like aholer would just come out and state clearly up front whether or not they are capable of hearing? Instead of hiding behind what someone else says, take responsibility. If you hear it, say so. If you don't, admit it.

Why the dishonesty?

I think the best way to A/B power cables is to first ask yourself, have I spent at least $3,000 - $5,000 on acoustic room treatments, and I would even go to $10,000.  If your answer is no, then worrying about your cables is a waste of time ... it is not the roadblock to the best sound. 

That out of the way, unless you can get a friend to swap them for you without telling you which is which, it is unlikely you will subjectively test your cables and come to an accurate conclusion, even about your own likes.  Ya, sure, tons of people here will disagree with me, but if you don't believe me, go to an audio show, go to all the rooms and listen, don't ask how much anything costs, don't even look too closely at the equipment, and write down your impressions. Listen closely to the music, IGNORE the sales person trying to plant thoughts in your head. Then compare your notes to the "audiophile" press. Almost without fail, they will wax eloquently about the most expensive systems .... you know $200,000K of fancy equipment in the equivalent of your mom's basement .... hard walls (and in hotels usually cement ceilings), little to no room treatment, maybe even some strange shaped rooms. I don't care how good your equipment is, if the room is poor, the result will be poor. Perhaps not Bose poor, but a properly treated room for 1/10th the price can easily sound better (and often does).

Some of the cable guys are pretty smart. They will put a ton of work into the acoustics of the room .... and it will sound really good. They will say it is their cables ... it is not. 

It is your money though. Do you want sound or jewelry?
I think this topic jumped the rails pretty quickly. My bad. Reading my original post, I realize this is my fault. I know enough to understand that the cable debate is a heated one and is very subjective. I understand that no one can tell me what is "best" for me or my system. 10-4. Got it. 

I think what I *meant* to ask was this...
What is the best way to test system quietness? Is it as easy as hitting "pause" on a source and then cranking all gain adjustments to the maximum setting? Would this allow me to amplify any noise in the system and possibly measure it with a decibel meter? 

Seems like a potentially interesting experiment, but I wanted to ask before I did this. 

That's it. I will now duck under my desk and await your replies!
don't waste your time measuring cables it's all about the tone you like. from my experience some cables make a difference that i can hear and some don't. 
to my opinion the center of your quest should be your ears not some noise meter .you are centering on specs or measurements that really mean nothing to us unless we notice it with our ears. with your system it's a crime not to use proper cables and at that level they should be treated like components(they also cost like components). before you change a component you should think about what tonal change would you like?  what are you replacing and why? for example if you want a faster detailed sound or  to open the soundstage and all your rca's and speaker cables are copper maybe silver  cables are for you.how much warmth will you trade for speed?well..that's where the experiments should be .i advise not to spend a cent on ac solutions and power cables unless you hear a noise or problem that it will solve .there are many audiophiles that say that it has a bad effect on tone especially power conditioners.



@temporal_dissident; I suggest you do exactly what you stated at the beginning of your post with the five points you listed.

"Is there some more objective way to A/B test power cords and interconnects?"

 Although you will receive a number of different answers I'd say keep life simple and fun and enjoy the music as you make comparisons.

Wouldn't it be a whole lot more honest if people like aholer would just come out and state clearly up front whether or not they are capable of hearing?


Wouldn’t it be *honest* to address the content of someone’s post rather than drag out the hoary old audiophile ad hominem that suggests someone’s hearing is faulty if they don’t hear what you think you hear?


No, a ground loop happens when there is a different voltage potential between two or more grounds.
What I said cleeds. Read it again.
I’m not hiding behind anything. I don’t hear differences between interconnects, speaker cables, and most amps. Or rather when I’ve sat down and done *immediate comparisons* the differences aren’t there. In that sense, I’m like....everyone else, apparently.

But I’m just one guy with biases, like you (perhaps even a bias *not* to hear a difference, the opposite of the problem Stereophile ran into). Larger population, properly conducted blind studies are much more compelling evidence than my individual experience, and thus more relevant to the OP.

And it is "ahoFer" (capital for emphasis), but you knew that.
Wouldn't it be a whole lot more honest if people like aholer would just come out and state clearly up front whether or not they are capable of hearing? Instead of hiding behind what someone else says, take responsibility. If you hear it, say so. If you don't, admit it.

Why the dishonesty?
Fast switching is far more revealing than long term tests; auditory memory is less reliable as time goes by. Here’s a good synopsis of a paper on the subject:

https://www.audiosciencereview.com/forum/index.php?threads/aes-paper-digest-sensitivity-and-reliability-of-abx-blind-testing.186/

I’m a cable skeptic, which puts me in a (somewhat reviled) minority on this forum. But the evidence is clear that for all the differences audiophiles write about with respect to cables, the perceived differences utterly and completely fail to replicate under scientifically controlled conditions.

We don’t listen under controlled conditions, and that is certainly also something to think about - you should buy what will make you happy in your listening at home. But the overwhelming testing evidence should give you pause as to whether you should spend any money at all on fancy cables.

You should absolutely conduct some AB (or better ABX) tests, blind if possible, with as quick a comparison as you can manage. But then do what makes you happiest with your newly expanded knowledge.

Here are two good thread with compendia of various blind tests:

https://www.head-fi.org/threads/testing-audiophile-claims-and-myths.486598/

https://hydrogenaud.io/index.php/topic,82777.0.html

Specifically for cables

http://djcarlst.provide.net/abx_wire.htm

and stay tuned for the surprise reveal at the end of this one:

https://www.audio-forums.com/articles/interconnect-cable-blind-listening-test.15/

You might also want to look at Ethan Winer’s null tester results - the cables aren’t even sending significantly different signals, so why, exactly, would the speakers behave differently when presented with the same exact electrical signal?

https://www.audioxpress.com/article/you-can-diy-building-a-null-tester-device


IMHO you don't need a double blind ABX test to evaluate a cable vs. another (or any audio equipment for that matter). When you hear it, you will know. If you have a hard time hearing the difference not blind, then it's not worth it doing the change. When you immediately hear the difference, then you will know right away. Then swap back to "old" cable, and give it a listen. As simple as that.

Good luck! it's fun, just take your time with it, and keep an open mind
By listening of course, you compare them with different type of music,from jazz, classical, folk song, rock, reggae, vocal, speed, layering, bass midrange,extension, musicality, to see how this Cables sounds , performs on each type of music..Get silver, copper, liquid cables, solid core or strand.This is a lot of work, but it pays off.
millercarbon
The risk of a ground loop comes in when you connect together components that are connected to different outlets.
No, a ground loop happens when there is a different voltage potential between two or more grounds. The number of or AC circuits used in a system is irrelevant. With the proper use of dedicated lines, the ground voltage potentials should be identical.

I’m confounded as to how anyone could think multiple dedicated lines could cause DC offset.
My goodness, what a lot of misinformation!

If "auditory memory isn't all that long" then how is it a woman ever remembers what the cry of her baby sounds like? Or since this is mostly guys, I guess whoever believes this has no idea how their car sounds or when it isn't running right. Duh-oh. Nonsense on stilts.

(Not telling anyone they can't hear. Anyone says they can't hear, take them at their word.)

With wiring as with a lot of stuff where you're trying to get at the truth I find it helps to filter, one of the best being, "How does he know what he's talking about?" Everyone has an opinion. But what is it based on? Good to know.

Some people have a wealth of experience. Others, not so much. Mine goes beyond the normal book-reading, even beyond the book-reading of a radiologic technologist (electronics, physics) and well into practical, immediately relevant actual hands- and ears-on experience.

1. Wired circuit breaker panels.
2. Wired listening room, conventionally.
3. Wired listning room, dedicated line but to code.
4. Wired listening room 4 ga.
5. Wired listening room 4 ga 240v with silver step-down transformer to 120v.
6. Cryogenically treated 4 ga circuit.
7. Critically listened to all the above with a pretty damn fine system in a dedicated room acoustically treated over a period of 30 years.

That's the Cliff Notes version. 

The risk of a ground loop comes in when you connect together components that are connected to different outlets. Electric current always takes the path of least resistance. If the resistance to ground is exactly the same on both circuits fine, no problem. But how often is anything ever exactly the same? So you run the risk- not a certainty but exactly what I said the first time, risk- of ground loop hum.

DC offset is a little harder to explain but similar, in that it is a risk not a certainty. Which is why I said you run the risk. And why? See the 7 items above. If there's one thing I'm sure of its that there is no benefit to running more than one circuit for a system. 

When it comes to comparing cables, I've held parties with over a dozen people in the room. Usually only a few audiophiles and mostly just people who enjoy music. One of the best, Caelin (Shunyata Research, that Caelin) came over with some power cords. We would play some music, change a power cord, play some more music. Never once did we play the same track twice. Hard to think of anything more boring or likely to make one lose interest, just the opposite of what you want in a comparison. Never once did we have any one of the dozen or more not notice and appreciate the differences. Being non-audiophiles they don't know the lingo but believe me they are sure they hear the difference and they know what they like.

As reprehensible as it is to remove informative and useful information just because some snowflake got their panties in a twist, it winds up being rather self-defeating when the subsequent response is even more withering.

So there you go.


First, to me, nothing is as valuable as the buyer’s pleasure. Whether pleasure of ownership, pleasure of listening, or pleasure of DIY, it’s your money, so do what you want to with it. Kids jerks? Spend their college fund. No problem from me.

But I do think that you are making choices about how you train your brain. It’s not all about what you buy, it’s what you tell your brain you want to focus on.


Lets say you train your brain to listen for the difference between silver plated interconnects, and braided gold. OK, great. You can hear it. How is that a goal that was worthy of you? Maybe it is.


Point is, a lot of things may not sound different at all. Some may sound different but not better.


Are you setting up your tests to guide your ear/brain mechanism to a happier place? If it takes you 20 hours to find a difference between two products, was that worth while?


If some one were to switch your chosen interconnects with other types, would you know in an hour?

Only you can answer these.


Best,

Erik
Skeptical?  Nah.  They work and there is a discernible difference.
All depends on your tastes (like wine, as stated) and budget.

Just switched to streaming. System sounded great. Then I looked at what my installer used for an ethernet connection. It was a basic cable but they said, you don't need anything else.

Had a used SR Atmosphere ( last gen.)  sent out on trial basis and the difference was very, very noticeable. The ethernet cabling draws a lot of skeptics BUT I found it the best $350. I have spent.

Cables, power cords are part of a system. They work but not cheap tweaks and can become a money pit  Good luck.
Being new you have no way of knowing we have someone here with near zero experience and practical knowledge who nevertheless loves to opine as if he were an expert on every subject imagineable. He doesn’t even know what a ground loop is, couldn’t explain it even if his life depended on it, yet feels compelled to post again and again all the same. Or as he himself woud put it, he feels compelled, obligated and driven to post, state, or say similar nonsense, falsehoods and misinformation, many times, repeatedly, and often.
If the OP could have a second person switch cables so he isn't able to know what has been switched, might be a way to A/B.
B
Auditory memory is not long.  Still, best to play one cable/component for a while, to get thoroughly attuned to it, and then swop in B.  Be SURE that the last track you played with A is the first track you play with B. Best chance of putting your finger on what you hear different. Thereafter, let B settle a bit, and check your emotional responses.  Do you feel pretty much the same listening to both, or more involved with one over the other.
If one wants guaranteed impassioned and contradictory responses, all one has to do is to start another topic about cables!
I was really hoping the first two responses to my question would be both impassioned and contradictory!  Thanks guys!
Post removed 
millercarbon"First, you don't need lines for power and source. Not only is this a waste of time and money, you run the risk of introducing ground loop hum and/or DC offset causing transformer noise."

This is false and misleading for one thing it should be immediately obviously, clear, and apparent that using dedicated AC cannot possibly introduce, cause, or create DC offset in a component that is an absurd assertion, belief, and opinion as for dedicated lines if properly designed, installed, and implemented that will not cause an ground loop and in fact can prevent them.
First, you don't need lines for power and source. Not only is this a waste of time and money, you run the risk of introducing ground loop hum and/or DC offset causing transformer noise. Whole system on one circuit, another circuit for lights and miscellaneous outlets, all you need. Been there. Done that.

As for objective, absolutely the wrong word. Like asking if there is an objective way to choose wine. You pour, look, swirl, sip. Done. If the next guy doesn't like your pick, guess what? That's HIS problem.

Besides, its not like its all that hard to hear these diffferences. What you do, get yourself a Synergistic Research Master Coupler, basically the gold standard of power cords for like 30 years now. Just get one. Used they're around $250 or so. Totally worth the money. Then compare whatever else the other guys around here throw at you. Should not be hard at all to discover they don't even come close.

Then do the same with the rest. Find whatever Synergistic interconnect and speaker cable you feel comfortable spending whatever amount of money on. Does not matter. I have not since 1991 ever heard anything else perform as well across the board, and doubt I ever will. So you get one, then feel free to compare away. Won't be long before you will be thinking what's the point? Just get the newest/best SR you can afford and relax and enjoy the music.... until you start wanting the next one....