Power Cable for a Bass Amp Question

[Bob Lee (QSC)]

Originally posted by throbbinnut
I read an article once about Belden doing a type of speaker cable test in which they let the listeners see which cable they were listening to. Each time the speaker wire was changed, the reviewers would go on and on about how much better some aspect had gotten with the magicable, or how much worse it sounded with zipcord in place. The author said he couldn't bring himself to tell the guys when it was over that the speaker cable had never really been swapped - the lab techs had been instructed to walk behind the amp and speakers and make it look like they were swapping cables - they had been listening to zipcord the entire time!

I wish I could find a link to that article.

Chris

Ah, look here: [Invalid or Expired Link Removed]

 

[ivanthetrble]

That link is too funny! Ah, the power of suggestion.

 

[BillyB_from_LZ]

Meekster, I'm with you... Whodathunk that this thread would fester into this mess when it started out with some poor guy asking if an plain old power cord was good enough for his 400RB.

 

[throbbinnut]

Bob, that's the one! Thanks for the link.

More gas for the fire at this link!

Link Removed

As my Emag2 teach used to say everytime he solved a problem on the board:
"Aha, Science wins again!"

Chris

 

[Jim Dombrowski]

Anything you read at audioasylum.com, take with many grains of salt. There's a lot of mythology and superstition passed off as fact there.

Bob: Chill out a little. The guy was asking about reference materials for tube circuits, so I provided a link where he could find more info.

 

[Bob Lee (QSC)]

Originally posted by jdombrow
Bob: Chill out a little. The guy was asking about reference materials for tube circuits, so I provided a link where he could find more info.

Most who know me say I couldn't possibly chill out any further.

 

[throbbinnut]

Originally posted by ivanthetrble
What in that cable makes it sound better and cost 50 times more than a computer cable?

What makes it cost more?
A big fat paycheck to all the charlatans involved.

Chris

 

[Schwinn]

Originally posted by metron

But there's a thread going around which is similar to this one except they're talking speaker cables instead of power chords.QUOTE]

Speaker cables and power cords are apples and oranges. Speaker cables IMO are open to debate as to their effect on audio quality. Power cords are not. They are effectively isolated from the audio signal path. As has been said the power of suggestion is strong. Analysis using physics and math is not subjective.

Edit: I HATEd electromagnetics.

Right on! At least instrument and speaker cables are in the audio signal path, so their effects on sound can be debated. On the other hand, this stuff about power cords...!

 

[Bob Lee (QSC)]

Originally posted by metron

Speaker cables and power cords are apples and oranges. Speaker cables IMO are open to debate as to their effect on audio quality. Power cords are not. They are effectively isolated from the audio signal path. As has been said the power of suggestion is strong. Analysis using physics and math is not subjective.

You are correct.

But even the speaker cable issue is not alien to physics; i.e., the more the cable resembles a direct connection where the amp output and speaker are in exactly the same location, the more it approaches the ideal. To approach the ideal, the speaker cable needs to have extremely low series resistance, especially since it is in a low-impedance circuit. Therefore, the length and thickness of conductors are important. It must also have low inductance and low shunt capacitance, but these two requirements aren't difficult to meet, even with ordinary zip cord.

 

[HassBacker]

I might be blowing smoke, but it seems to me that all things being equal, the only thing that would make a difference here would be the quality of the connection being made by said power cable in the amp input socket and the supply outlet. A higher resistance connection on the ground might cause some noise on the mains not to be filtered properly. Interesting reading! JD

 

[Jim Dombrowski]

I have to disagree about audio signals and power signals being completely separate. They come from two different sources, and have different characteristics, but in the amplifier it's all electricity and I can't help but believe that they can be affected by each other.

I believe that power cords can make a difference in some amplifiers (or highly revealing systems). Can I prove it? No. But, there are numerous other mysteries in this world that have been proven or explained over time, and I think this is possibly one of them. I've heard too many people talk about different power cords having a positive affect in their stereos to dismiss it all as snake oil. Is some of this a placebo affect? Probably. But not all of it.

Almost all the facts that people base their arguments on are from electrical measurements taken at the wires, or audio measurements taken at the speakers. But none of that correlates completely with what we hear. How do you know that there isn't some unmeasured affect occuring around the wires and circuitry that is affected by changing a power cord? It's been said here before: keep an open mind. Just because you believe (or disbelieve) doesn't make it fact.

However, having said all of that, I'm not proposing that changing the power cord on every bass amplifier will necessarily make a noticeable difference, or that it's worthwhile to do it. But I do believe that the right combination of amplifier and power cord could be an improvement.

If I was a studio musician, I would pay much closer attention to these details.

 

[Ben Alman]

my power cord is built into my amp, I guess I'll never know what I'm missing

 

[ihixulu]

I have to disagree about audio signals and power signals being completely separate.

The fact that you are alive to disagree is a testament to the fact that the audio and power are separate. If they weren't you'd be playing bass with 120V strings.

Look, if there is an actual effect as a result of changing a component, it will show up in some measurement. SOME measurement. How that change is perceived is totally subjective but a change has to be there. Otherwise it is just placebo, which is fine for people who have $175 to spend to feel special.

I'm thinking rather than any kind of listening test, they should just pump white noise through the amps and map the difference in output when the cables are changed.

 

[Richard Lindsey]

Originally posted by jdombrow
Almost all the facts that people base their arguments on are from electrical measurements taken at the wires, or audio measurements taken at the speakers. But none of that correlates completely with what we hear.

But a big part of the issue is precisely the question of "what we hear." Are we in fact hearing it or only thinking we're hearing it? That was the point of the various posts about the shortness of audio memory and about the necessity of properly controlled double-blind testing. Outside a good testing environment, claims to have heard nebulous differences don't mean much.

Sure, there could be some variable we don't know about. But before we even get to that, you have to *establish that there is even anything there that needs explaining*. IOW, you have to show that there's an audible difference and that people can consistently detect it with significantly better than chance accuracy. If testing shows that people can't reliably detect this supposed great difference, then there's nothing that needs to be explained. There's no real difference, and no new and mysterious explanatory principle needs to be adduced. OTOH, if people can reliably detect it, *then* you go after the explanation.

 

[Bob Lee (QSC)]

Originally posted by Richard Lindsey
But a big part of the issue is precisely the question of "what we hear." Are we in fact hearing it or only thinking we're hearing it? That was the point of the various posts about the shortness of audio memory and about the necessity of properly controlled double-blind testing. Outside a good testing environment, claims to have heard nebulous differences don't mean much.

Sure, there could be some variable we don't know about. But before we even get to that, you have to *establish that there is even anything there that needs explaining*. IOW, you have to show that there's an audible difference and that people can consistently detect it with significantly better than chance accuracy. If testing shows that people can't reliably detect this supposed great difference, then there's nothing that needs to be explained. There's no real difference, and no new and mysterious explanatory principle needs to be adduced. OTOH, if people can reliably detect it, *then* you go after the explanation.

Amen to that, Richard. Well said.

 

[Petebass]

You know what would be good right now? Input from a psychologist. It would be interesting to know the the mechanics of the brain, in particular in regards to perceptions and expectancy set.

 

[embellisher]

Originally posted by CkB_Cowboy
my power cord is built into my amp, I guess I'll never know what I'm missing

Second only to GooseYard's post for best in thread!

 

[GooseYArd]

Originally posted by Petebass
You know what would be good right now? Input from a psychologist. It would be interesting to know the the mechanics of the brain, in particular in regards to perceptions and expectancy set.

Although we might not get him to actually post here, Daniel C. Dennett has an excellent book "Consciousness Explained", that goes into tremendous detail about the impact of suggestibility in experiments that are designed to measure perception. A lot of the experiments are visual but even those apply. It's a pretty dense read but it's a bonanza of information on how unreliable human subjects are in detection. Although our apparatus are pretty sound, the people at the controls are generally nuts.

 

[GooseYArd]

Originally posted by jdombrow

I believe that power cords can make a difference in some amplifiers (or highly revealing systems).

This is precisely the problem. For some reason, humans have a stronger need to believe anything than to believe specifically those things which can be proven true. Leads to all kinds of oddness, perhaps the least of which being that if we start with believing something, our senses will seem to favor conclusions that are in line with that belief.

If you put the cart (belief) before the horse (careful and deliberate study), then you wind up going in an odd direction, if anywhere.

 

[Bob Lee (QSC)]

Originally posted by GooseYArd
Although we might not get him to actually post here, Daniel C. Dennett has an excellent book "Consciousness Explained", that goes into tremendous detail about the impact of suggestibility in experiments that are designed to measure perception. A lot of the experiments are visual but even those apply. It's a pretty dense read but it's a bonanza of information on how unreliable human subjects are in detection. Although our apparatus are pretty sound, the people at the controls are generally nuts.

I'm not familiar with that book, but it sounds interesting.

The non-blind listening tests I've witnessed (in hi-fi shops, pro audio retailers, etc.) almost always seemed to tend to turn into "hearing contests," with the participants seemingly feeling it was their own hearing being evaluated instead of the amps, speakers, et al. This increases the pressure on them to perceive differences that do not necessarily exist.