A cable experiment for non believers...

[sjoc2000]

I have been using a Radio Shack S/PDIF digital coax cable from Radio shack for transmission from the computer to Dac, cost $15. Although I am familiar with the fact that the transmission of electrical signals is a field unto itself, and deserves serious consideration in many circumstances, I have been slow to consider it's importance in audio systems.

 

As I have read and followed some of the discussions here concerning signal transmission, both subjective and objective declarations about how different kinds of cables, other than those satisfying the fundamental requirements for appropriate transmission of a signal, can make a qualitative difference in what finally emerges from a speaker, I have been less than convinced. But...

 

I have been giving some thought to impedance matching since I am familiar with this problem as a ham radio operator. I have asked here, and looked in vain on the net for information, other than the obvious, about what the affects of reflective waves in digital transmission may be. It may be that some of what audiophiles report as improvements due to different cables has to do with this factor, that is the affect of reflected waves upon the source wave. Of course "real" balanced XLR systems should, in theory, resolve this potential problem.

 

There are other objective analytical approaches that may shed some light on cable construction and resulting reports of improved sonics. 3 dimensional as opposed to simple 2 dimensional analysis of waveforms being studied, etc..

 

I decided to try a simple experiment, that others may wish to try. I had a standard 75 ohm 1/4" video cable laying around from a tv hook up. It is constructed very well, with a shielded dielectric. Although it just has standard plated RCA connectors, I decided to see if it would make a difference as a replacement for my Radio Shack S/PDIF digital cable.

 

 

I was surprised. I thought I had my system working toward the top of it's potential. The simple cable replacement made quite a difference. I listen to a lot of classical music. Instruments became better defined, and instrumentation in orchestrations became better delineated. If I may, the colors of the music became brighter and clearer. A big difference to these ears.

 

This occurred despite no cable BNC connectors, no rf attenuators, nor BNC on the Asus output nor the Dacit input. I suspect that further improvement would be realized with these additions.

 

For those who may wonder if I have a bad Radio Shack S/PDIF cable? I have another inexpensive cable here, $10 at best buy, and it performs exactly as the RS cable performs.

 

Conclusion. A cable with a thicker dielectric that is shielded, constructed as a 75 ohm cable as compared to a standard "Audio S/PDIF Digital Coax Cable" was significantly superior in transferring a PCM signal from a bridge to a Dac, and resulted in superior sonics.

 

It's simple enough to do, you shouldn't have any trouble finding one of these video cables somewhere. For the non believers and inquisitive, try it, you'll be surprised. It would be nice if those who try, will share there results...

 

 

Jim

[sandyk]

Hi Jim

I have already done similar with the same results. My old cable was made from a damaged (connector only) Telstra Carrier System 75 ohm coax patch cord. It was a beautiful white THICK coax with excellent screening and a thick inner conductor. Much to my surprise it was outperformed by a cheap Digitor coax lead from Jaycar of the same length.

Regards

Alex

[Paul R]

It's a blinking amazing thing isn't it? It should not be possible, yet it is. Of course, many would argue that is just a case of fooling ourselves and fight to get one to admit that it is at least possible we are fooling ourselves, which of course, it is. Be we are not and they Just Don't Get It.

 

ditditditdit ditdit

 

-Paul

[wgscott]

Or one could argue that the Rat Shack cable was genuinely a product of sub-standard, inferior construction, much like many optical toslink cables are. I can't speak for anyone other than myself, but in general, I think the skeptic's position is that if there is an audible difference, it should be measurable.

[Paul R]

Oh, I agree, but I also think that ears are a reasonable measuring tool to use for these kinds of measurements. As well as a scope. I don't trust the scope any more or less than I trust the ears. Either one or both can easily be in error.

 

Paul

 

Or one could argue that the Rat Shack cable was genuinely a product of sub-standard, inferior construction, much like many optical toslink cables are. I can't speak for anyone other than myself, but in general, I think the skeptic's position is that if there is an audible difference, it should be measurable.

[sandyk]

Conclusion. A cable with a thicker dielectric that is shielded, constructed as a 75 ohm cable as compared to a standard "Audio S/PDIF Digital Coax Cable" was significantly superior in transferring a PCM signal from a bridge to a Dac, and resulted in superior sonics.

 

Hi Jim

Unfortunately ,my conclusions do not agree with yours. My original cable was superior in the aspects that you mentioned. What I didn't do , was to measure the capacitance of both cables, or pull the new cable apart to see if it had a silver content.

Some coax cables may also have an inner that is steel, but copper plated.

Regards

Alex

[spdif-usb]

Personally, I, prefer a generic USB cable on a DAC that has both proper galvanic isolation and properly implemented async USB. It saved me one heck of alot of money and IMO it even sounds better.

[sandyk]

Personally, I, prefer a generic USB cable on a DAC that has both proper galvanic isolation and properly implemented async USB. It saved me one heck of alot of money and IMO it even sounds better.

 

Much depends on the DAC itself. My modified Silicon Chip magazine designed DAC, both from my Asus Xonar D2X via coax SPDIF, as well as a friend's Asus Essence W7 soundcard, outperforms a Steve Nugent OffRamp into this DAC, and even a Perfect Wave Transport. Both Async USB and coax SPDIF are capable of excellent performance when properly implemented.

It;s all about power supply, power supply and power supply.I think you will find that Barrows agrees with that too.

Alex

[Jud]

Or one could argue that the Rat Shack cable was genuinely a product of sub-standard, inferior construction, much like many optical toslink cables are. I can't speak for anyone other than myself, but in general, I think the skeptic's position is that if there is an audible difference, it should be measurable.

 

Sure, but what measurements? Is measuring the cable itself adequate, or is it essential to measure the entire system? What aspects of the system? More or less easily measured electrical characteristics and frequency response, or sensitive jitter measurements with expensive lab equipment? And which of the various measurements are most critical to the actual listening experience? Which can be left out and not do irreparable harm to the correspondence of the measured differences with discernible acoustic differences?

 

I think there are some answers to these questions, though perhaps not entirely complete ones.

[mayhem13]

I'll agree with the OP, that an upgrade over a generic digital interconnect can produce an audible difference as I have experienced it going from a $10 TosLink to a $60 glass TosLink which I attributed to the connectors and overall quality. But I would also add that IMO, there's also a point of diminished returns, if any returns where interconnects are concerned.

[wgscott]

Sure, but what measurements? Is measuring the cable itself adequate

 

My point was that the so-called objectivist position isn't that such differences cannot exist, but merely that such differences don't arise from unmeasurable, unknowable phenomena, i.e., if there are audible differences due to the cable itself, then there must be physical differences that are reproducibly measurable within the cable itself.

[4est]

My point was that the so-called objectivist position isn't that such differences cannot exist, but merely that such differences don't arise from unmeasurable, unknowable phenomena, i.e., if there are audible differences due to the cable itself, then there must be physical differences that are reproducibly measurable within the cable itself.

 

I think Jud nailed it, and I find it silly that many cannot fathom that we simply do not yet know how to measure it well enough out of circuit, and that most people do not have the capability (knowledge or spare change around to own a proper analyzer) to measure in circuit.

 

It is too bad CG got driven off by all of the BS, his views on this stuff were enlightening.

[sjoc2000]

Or one could argue that the Rat Shack cable was genuinely a product of sub-standard, inferior construction, much like many optical toslink cables are. I can't speak for anyone other than myself, but in general, I think the skeptic's position is that if there is an audible difference, it should be measurable.

 

 

"For those who may wonder if I have a bad Radio Shack S/PDIF cable? I have another inexpensive cable here, $10 at best buy, and it performs exactly as the RS cable performs."

 

Jim

 

The world of the skeptic is a place I am not uncomfortable with. As stated above I had two of these cables, and both behaved the same.

 

I agree completely, if you hear a difference (dependent variable), you should be able to measure this change, but more important is that you should be able know what you are changing (independent variable), and by how much.

 

All that can be concluded is that I heard a difference (a pleasant one to the ears), and report what was done, so that others can try the exercise. It may be that there is agreement from others, which will help to prove that I am not reporting a delusion. :0)

 

If we can find agreement about the change, the problem remains with what is the dependent variable, and precisely how it is being changed. It is implied in the first post that an examination of the affects of reflected digital signals (due to impedance mismatch), and their affect on the source data streams may be part of the answer. This examination needs to be more in depth than just a checksum or a null test. The expertise to do such an examination is far beyond me.

 

It is also implied in this post that one of the independent variables may be "impedance". That is that the video cable has inductive, capacitive, and overall resistive qualities that are less reflective, and therefore the source signal arrives at the Dac more closely resembling the original data source than with the standard Radio Shack Audio S/PDIF digital coax cable.

 

Hope others can try the exercise...

 

Jim

[57gold]

wgscott,

 

Try one of these, an audiophile approved (whatever that means) digital coax from a guy who has been making them for audio purposes for years. Makes a $150 one with a money-back guarantee.

 

Silverstar 75! | Black Cat

 

Had a Veloce, his previous model which was $123, and it connected the WaveLink to my Wadia DAC and bumped the clarity factor nicely versus an inexpensive one from WireWorld that Wavelength included in w/the WaveLink.

 

Love the hear your opinion on this swap.

[Jud]

My point was that the so-called objectivist position isn't that such differences cannot exist, but merely that such differences don't arise from unmeasurable, unknowable phenomena, i.e., if there are audible differences due to the cable itself, then there must be physical differences that are reproducibly measurable within the cable itself.

 

Agree virtually completely, the only caveat being that I'd insert a parenthetical "(in principle)" after "reproducibly measurable." That is, I'd allow for the possibility that we may not yet know everything that should be measured. I think that may be similar to your use in the previous sentence of the word "unknowable."

[Paul R]

Why don't you try the same test and report back your results? It would be much more informative than trying to pick apart Jim's report, whether or not your results duplicate his or not.

 

I do get you are saying that you personally would want different substantiation than your ears before spending money on a cable. Is the reverse true? Do you want different substantiation besides your ears for spending less on a cable?

 

The OP tested a $10 cable against a $0.50 cable from a TV hookup and found the $0.50 cable was superior. Even tested against a second $10 cable.

 

By most logic, that should not be. Yet, it is.

 

In any case, it would be great to see how the $0.50 TV cable stacks up against a $25, $50, $100, or more expensive cable in the OP's system. Not that I want him to spend any money doing it, but I could be coerced into chipping in $5 towards a rental from the Cable Co. Sheerly out of curiosity.

 

-Paul

 

(Or I could have read the original post wrong, and this was an expensive brand name video cable, but I don't think so. )

 

I have a few issues with this alleged improvement.

 

The spec requires a 75 ohm cable. If the cause is radio shack selling a cable that isn’t, well shame on them. I don’t think this is the case. The likelihood that it’s an impedance matching issue is pretty close to zero.

 

Second, given the strength of confirmation bias, this is not the sort of report you can take to the bank.

 

Let’s say there was some improvement. That one commodity cable sounded better than another commodity cable doesn’t mean that there’s any justification of wasting money on interconnects that cost hundreds or even thousands of dollars.

[sjoc2000]

Hi Jim

Unfortunately ,my conclusions do not agree with yours. My original cable was superior in the aspects that you mentioned. What I didn't do , was to measure the capacitance of both cables, or pull the new cable apart to see if it had a silver content.

Some coax cables may also have an inner that is steel, but copper plated.

Regards

Alex

 

Hello to down-under land;

 

I hadn't thought about this before, but a report of a decrease in sonic quality may be as important as an increase. If a cable is just a neutral transmission medium, then there should be "no difference".

 

It's nice to experience an increase in sonic quality, but there may be a decrease as well. The thinking here in terms of impedance would be that if a cable is introduced which results in a decrease in sonics, then it is because reflective qualities of the cable are such that there is an increase in interference to the source digital data as it moves through the transmission line.

 

The impedance of any system will be specific, unless it is designed for a certain value throughout, as with the implementation of balanced inputs and outputs for the components of an audio setup. This being the case, then each input (Dac?) and output (converter?) will likely have their own impedence, as will the connectors, as will the cable that is being used. It would seem to be a kind of russian roulette to just throw a cable in a system, it may help or not. To get the greatest benefit the cable should be specific to the system into which it is being placed. This may be why there are such varying reports on cables and resulting changes in sonic qualities.

 

This emphasis on impedance is just an idea, that may be correct or incorrect. It would seem to warrant further study and investigation, especially where digital audio systems are concerned.

 

Jim

[57gold]

The Black Cat is returnable, from a noted digital "cable guru" and coax specialist with no rental fee other than postage.

 

wgscott is the perfect guy for a trial like this...no BS marketing will influence him.

[Paul R]

Is there another source for that cable? It seems it is being replaced with a newer model, and the cable is not available.

[57gold]

Sorry, I didn't try to buy one.

 

Checked site and saw that Veloce, one that I enjoyed when I needed a BNC hook up, was replaced with a tweaked new version Silverstar 75!...assumed it was available.

 

Bought my Veloce from Black Cat directly, so not sure if MBG is available from their dealers.

[4est]

Sorry, I didn't try to buy one.

 

Checked site and saw that Veloce, one that I enjoyed when I needed a BNC hook up, was replaced with a tweaked new version Silverstar 75!...assumed it was available.

 

Bought my Veloce from Black Cat directly, so not sure if MBG is available from their dealers.

 

57: Did you notice a difference between the Veloce and the Silverstar?

[wgscott]

wgscott,

 

Try one of these...

Love the hear your opinion on this swap.

 

I don't have anything (except a Samsung $50 DVD player) that I could use as a source.

 

The Halide Bridge I have has a coax connector to the unit itself -- no cable.

[wgscott]

I think Jud nailed it, and I find it silly that many cannot fathom that we simply do not yet know how to measure it well enough out of circuit, and that most people do not have the capability (knowledge or spare change around to own a proper analyzer) to measure in circuit.

 

Another (simpler) possibility is that the O.P.'s rig is situated somewhere that RF interference is more problematic than normal, and the TV cable simply does a better job because it is better insulated from such interference.

 

It is too bad CG got driven off by all of the BS, his views on this stuff were enlightening.

 

He left because of me?

[4est]

He left because of me?

 

I was not thinking of you Bill, or anyone in particular.

[sandyk]

[quoteAnother (simpler) possibility is that the O.P.'s rig is situated somewhere that RF interference is more problematic than normal, and the TV cable simply does a better job because it is better insulated from such interference.

]

In my case, the Coax was from SPDIF Out from an Asus Xonar D2X Sondcard to the transformer coupled input of a Musical Fidelty X-DAC V3 sitting on top of the PC. The improvement I noticed with the $15 replacement lead was an incrrease in Soundstage depth when listening through a headphone amplifier.I certainly did not expect to hear this difference as only days before I had posted in HFC Forum that I doubted that simply replacing a 1.5M long 75ohm coax with another of the same length and impedance could possibly result in a difference in SQ.

Alex