|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
12.167.241.28
I have been an audio person for more than 50 years starting at 10 years old when I first experimented with tube amps. Worked some 40 years in radio broadcast engineering on many audio systems. When repairing or designing custom audio gear the process has always been run freq and distortion test first, then listen.
Occasionally I come across ads for audiophile components that I have to wonder what sort of test verify the claims other than it sounds wonderful. I happen to find a classified ad for a cable on another audio site that I would really question. First it's said to be an active cable, since there is no power source I can only assume it does not have any active components. Then they call it a pseudo balanced cable because they have run two wires through the cable with a resistance connected from each wire to the shield ground. In a balanced cable each wire is 180 degrees out of phase with each other so that any noise induced into the cable is then in phase and cancels at the balanced input. I went to their web site and I didn't see any mention of how they claim their cable works so I copied the classified ad and pasted below.
"After two years of development, Axxxx Txxxxxx Axxxx is excited to introduce our active cable system. This revolutionary technology expands the possibilities of any system. Unlike common cables, ACS allows the interconnect to act like a balanced (XLR) cable. Purity, huge dimension, and great detail are the hallmarks of this design. This auction is a limited time introductory offer so bid now.
Here is how ACS works. The signal lines are connected to the shield by a pair of specifically manufactured resistors. What is created is a pseudo balanced interconnect, as the shield is effectively neutral relative to both conductors. Relative to the equipment ground, the shield sees half the signal voltage swing. Einstein would ask, what if the wires do not know that ground is ground? The results are stunning! This creates a true actively shielded cable just like Synergistic Reasearch or Audioquest. The sound is holographic with the speakers disappearing and a gigantic soundstage is created. Only an active cable can do this. We need to talk about the importance of a good connector. Large chunks of shiny metal are like a roadblocks to your precious signal. We use world
famous, Swiss Neutrick connectors. These are a low mass design which may not look impressive but they deliver the sonic goods in a big way. The conductors are a proprietary, high conductivity, ultra pure material. Cable is 1m long."
The ad is completely void of any technical test data that one might expect, most likely because this cable can not possibly act as a balanced XLR cable. Regardless of how many wires they run through the cable it's still unbalanced. Since this is basically a high impedance unbalanced cable there may actually be some audio degradation from the extra wire capacitance in the cable.
I see other cable ads like this that use an array of descriptive words but no actual test data. If one were going to purchase a new amplifier you would want to see some actual test data. Why then would you not want to see some actual test data for an expensive super cable? For instance, just exactly what is the SWR (standing wave ratio) on a low SWR audio cable compared to a normal audio cable.
Follow Ups:
It's the audiophile industry. It is snake oil.Let me explain from a perspective most folks do not have. I was a designer/engineer for one of the most famous audiophile manufacturers. I was paid very well and was the primary designer for some gear I now see many people paying mega-bucks for, used. That makes me feel good. A validation as it were. However, I left the industry because I felt the direction it was taking was not in the best interest of pure reproduction of the recordings nor was it advancing the state of the art. It was instead a direction that made the products only sound different from other makers gear. Even if this meant adding distortion or making products that were not accurate, even though they were marketed that way.
Now they actually sell bonafide falsehoods, fakery and fraud. They wrap it up in mystical sounding techno-babble and perpetrate fraud on a ravenous bunch of audiophools ready to accept whatever nonsense is newest and different. These folks are not fools really, they just been wound up by this industry.
The fact is the state of the art has already been achieved or very close to it. However they do not want the buying public to be aware of this fact. The designs are now only limited by the electronic components characteristics (resistors, capacitors, semiconductors, etc). The circuit topologies have all been explored ad-nausea. The only improvements come about when the component manufacturers produce something new, which is very rare these days, especially with analog components. The biggest most recent advance in analog technologies was MOSFET and that was 30 years ago.
One recent example was a certain manufacturer came out with an anniversary model of one of it famous products. And it was sold for a kings ransom, in my opinion. The power supply design was ludicrous. There was so much reserve capacitance, (I believe there were something like over sixty high value filter capacitors). You do not need that much filter capacity. There is limit where you have all the filtering needed to maintain the lowest possible ripple under maximum load, so any more is superfluous. But that was the point, it looked cool under the hood so to speak. However, the in-rush currents were so high as to take out the power transformer over time. The time constants were also so high, that even with a step start, the power transformer saw an in-rush current twice it rated total current specification even after the time delay of the step-start. The step start circuit they designed to handle this in-rush also was way underrated for the currents involved, so it was prone to failure as well. And both of these problems reared their ugly head with many consumers who bought this great sounding, but poorly designed monstrosity. This is bad design plain and simple. However it was sold as a major step forward, a "state-of-the-art" power supply one "befitting the legacy of the (insert model number)". But with filter capacitors there is a definite and finite limit, before things become unmanageable and even dangerous. It's like putting a 500 gallon gas tank on a car and then marketing that the car will go faster. No mention of how big the explosion will be in an accident nor any explanation at to why such a massive reserve is even necessary.
So now you have a market where the buyers have been trained in believing they are getting the most recent state of the art. In reality as far as circuit design this ended about 20 years ago when that state was reached. So how do you do to keep them buying? What else? Lie. It's that simple and now is the standard marketing ploy.
Like the exaggeration of facts being advanced by the tonearm industry about 12" arms. They saw sever declines in sales once they sold the state of the art, and realized nobody had a reason to buy a new tonearm. So, start discussions about transcription tables and exaggerate how good they were (a lie in itself; they could just play the larger diameter discs which is why they needed a longer arm), and come up with a gimmick about how a 12" arm significantly improves tracking error distortion. This is true, however the gains are so infinitesimally small, if you actually take the time and do the calculus involved, it is beyond belief that anyone is buying into this. (In reality if you do the calculus the ideal length is a tad over 9" arm length for a 12" disc, but certainly not 12". And an arm slightly shorter then 12" for a 16" disc). But the whole industry is behind this exaggeration of fact, because the buyers are buying and everyone in the industry is benefiting.
These cables are nothing more then a deception. You are correct about why a balanced cable is actually balanced and why they work. Common mode rejection. Opposite phase reduces noise, reduces EMI, and lowers the RMS value on each leg. What he is producing is a wire with a load across the signal to ground. In this case, you have a capacitor being formed by the length of the two parallel wires, with a resistive load shunted to ground from each. So what does this create? An RC filter which will act as a low-pass filter, rolling off high frequency response in a gentle slope. What does this do for audiophiles? It's a really "warm" cable. So that's how you design audiophile products nowadays. Make it as far from neutral as possible so it sounds very different, market it with some very good techno-babble, and pay some reviewer to say "how warm and luscious it sounds", and you have an audiophile hit.
Let me explain one very good example. When I designed the power supply for one the best known power amplifiers even made, we had to specify a very heavy AC cable for it. The current draw of this amplifier was very high. So we used the same cable commonly used to wire electric stoves. Type SOWJ 8ga three conductor with a rubber jacket. Nothing special, just a good heavy cable that could handle the current with some headroom. Do you know I see published how we used some proprietary cable specially made for that amp. Both from comparative marketing by other manufacturers and in forums like this. This myth is commonly used for this insane notion about audiophile AC cables, which is another myth. The AC power drawn into audio gear is totally converted into a wholly different state of being completely by the power supply (if properly designed). Therefore, the "condition" of the AC is not relevant other than current draw which is solely a factor of wire diameter. The original AC and its characteristics no longer exist once the power supply is done converting it to DC, nothing of the original AC current survives along with any artifacts that may have been carried by it once this conversion is complete. A $200 AC plug improving sound quality? ... Humbug I say, and know for fact. It was stove cable I selected out of a Belden catalog of stock industrial cables. It was also cheap. Nothing special, yet the legend continues to grow and grow and ...
Snake oil, nothing more.
JRL
Edits: 03/25/13 03/25/13
"The signal lines are connected to the shield by a pair of specifically manufactured resistors. What is created is a pseudo balanced interconnect, as the shield is effectively neutral relative to both conductors."
Hmmm. In an unbalanced connection, one of the "conductors" is akin to a neutral conductor in a single phase system - it's simply a return path, as it is at ground potential. So you already have something that is 'effectively neutral'. So I'm not sure what is really being created here...
But I'm not a snakeoilcableologist. So I could be way off.
Cheers,
Presto
Aural Thrills. Apparently cable technology is not his only issue. A customer had problems with a pair of his amps and posted about it on the Shady Lane Asylum. To read the full thread, go to Shady Lane and scroll down about one quarter of the page to the "Aural Thrills Amplifier Issue" thread.
To the builder's credit, I believe he made good on the problem. However, there's a sub-thread that questions his technical savy when it comes to amplifiers. Use the link below to go directly to the sub-thread.
Gerry
There was another ad I looked at a few days ago for audio cables with low SWR based on RF technology. The ad seems to be discussing audio SWR but at audio frequency wavelengths SWR is not a factor. Further investigation seems to indicate RF shielding is the cables primary purpose. A product review provides enough technical babble to impress most anyone except I could not find any technical data of measured results of before and after using the wonder cable.
Using a multitude of descriptive words of how wonderful something is OK but I like to see some measured technical data. Any device that gives an audible change or improvement can be measured, things like RF or high level signal induced artifacts will show up in harmonic distortion measurements.
Yeah. This is the problem that I have with the entire audio cable industry, not just one company.
I recently purchased a Velodyne subwoofer. I noticed their literature said that their subs do not require expensive interconnects to perform up to their potential. Just a good quality, well shielded cable. I called their customer service dept to discuss this surprising recommendation. I was told that the company recommends only 'buying the best cables that you can afford'. Why would they recommend connections that do not allow their products to display their best performance?
I was told that they don't want to step on anyone's toes, but expensive cables are not required. In other words, they don't want to start a war of words with cable manufacturers (my interpretation).
I am currently using Radio Shack's best grade of shielded interconnects, and still manage to get holographic results with certain recordings. Better results than I was getting with Kimber Hero and Nordost blue heaven interconnects that I was using previously.
By the way, I switched the connections from my preamp to amp from RCA to XLR balanced and am very pleased with the improved sound quality. Again, no expensive cables were used.
For your balanced? Try Mogami Studio Gold from Guitar Center......
Not a 'magic bullet' cable, but all the fundamentals are right and so is the price.....
Too much is never enough
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: