Why do digital cables sound different?

Actually the SPDIF signal is digital, not dual-phase sinewaves. It appears more like a "trapezoidal" wave, which is a square-wave with controlled slew-rate rising and falling edges. This is to minimize radiated emissions for FCC regulations. The signal is around 3 MHz with 12-15 nsec rise and fall times.

While it is strictly a matter of semantics, the actual digital out signal from a transport is sent at 2.822 MHz. If one could resonate a cable that introduced a perfect non-reactive 75 ohm load at that frequency, you would end up with no standing waves. Bare in mind that terminating and feedpoint impedances are a LOT more complex than just selecting a 75 ohm cable ( we wish it was that simple ). This would allow the transport to load up easier due to a complete lack of reflections and a clearer signal path to transmit the data, which theoretically should drastically reduce jitter. This takes for granted that the transport and dac would both have nominal 75 ohm inputs & outputs though. This is something that i've been meaning to check into but just haven't gotten around to it. Sean
>

Looks like you're right audioengr. I got into an argument with Monstrous Mike one time about Manchester Biphase encoding. He was trying to say there was no digital edge, only FM modulated sine waves. From what I can find, you are right -- the signal is still sent as square waves from what I can tell (but not with sharp edges -- the standard should likely work even if the signal were closer to a sine wave, but with more jitter).

As for who I am Drubin, just an audio enthusiast, who lurks on the audoasylum cable forum under "audioNeil".

Picking up on what Redkiwi said about coax vs. digital, I and a friend were able to A/B the new Audioquest Optilink 5 with Audioquest's digital RCA, the VSD-4. The result was truly surprising. The Optilink glass fiber Toslink was significantly better in every way; soundstage, bass, "openness," highs, "air," -- you name it, the glass toslink was better, even though the data is just the same 0's and 1's. I don't have a clue why it sounded better, technically, but this was not even close. We were startled, honestly, at the difference. Moreover, the toslink was significantly louder at the same volume level, requiring us to match volume for the two. So bottom line is, for whatever reason, digital cables sound different, no question whatsoever.

Sean wrote:

If one could resonate a cable that introduced a perfect non-reactive 75 ohm load at that frequency, you would end up with no standing waves.

There may be no standing waves to a pure sine wave at that frequency, but you would certainly experience reflections with digital edges. There are only a couple of ways to eliminate reflections with digital signals, including:
1) series terminate (75 ohm driver) into a 75 ohm Zo cable - reflection from the end is absorbed at the driver.
2) parallel terminate a low-impedance driver into a 75 ohm Zo cable using a 75 ohm resistor at the end - no reflection.
3) Series and parallel terminate - (75 ohm driver) into a 75 ohm Zo cable with a 75 ohm resistor at the end - this cuts the signal in half, but eliminates all reflections.

Forgive me for coming late into conversation...

From what ive seen there is a major flaw in the spec itself The #1 contributer of EMI is the rise time. The quicker it
is the more EMI emitted. A common misconception is the Freq
is the culprit not true. Its seems to me that the rise times
are faster than needed for application. If some one knows why they used the 3mhz with a 12-15ns rise time... Please let me know? It doesnt make sense to me. Although those numbers are prehistoric it is asking for excessive EMI with
faster rise times than needed. Typically you would see a rise time more like 30 maybe as high as 80 for that type
of frequency.

Its like saying take 15min to drive to the store (a 5 minute drive) and then RUN in side and try and make up for lost time when you get there.

As far as termination I agree with Audioeng. You have have
termination in place at reciever end. Its the reflection back thats the killer... Backwards crosstalk is evil sh*t in any system.

Audioengr: Tara worked with terminating impedances years ago. Silver center conductor, Teflon insulation, Silver braided shield, 75 ohm resistor from center to shield at the load end. It is a very nice sounding cable and not bright in the slightest bit.

As far as having to use a resistor(s) to terminate the load, you would not need to do that IF the actual output impedance of the transport is 75 ohms, the cable is 75 ohms and the input of the DAC is 75 ohms. The problem is that none of these are exactly the correct impedance, so you have VSWR at the feedpoint, VSWR within the cable and VSWR at the load. If one could find out the actual output impedance of the transport and the input impedance of the DAC, it would be easy to make up a section of cable that would act as an impedance transformer. This would minimize standing waves / reflections and maximize power transfer. THAT was the point that i was trying to explain. Obviously, you could not market this cable as the specific values would change component by component.

As far as terminating the cable with a resistor at the load end, that would NOT solve an impedance mismatch at the source end. An impedance bump ANYWHERE along the signal / data path will result in reflections back to the source. Sean
>

Gentlemen,

There are always Impedance mismatches.. the trick is
to minimize... usually we have tolerances at 10%...Even
for high speed stuff. Impedance mismatches do cause RF current problems BUT if terminated it will be minimized.

A 10% mismatch ( VSWR of 2.0 ) at RF frequencies ( which digital data is transferred via RF ) can begin to play MAJOR havoc with some circuitry. I know that text-book theory states otherwise, but you have to realize that much of that theory was based on tube circuitry that made use of matchingn networks and tank circuits. Most SS gear does not have this type of circuitry, so loading characteristics become far more critical.

The severity of how much the operation of a device would be affected obviously depends on the stability of the circuitry and whether or not the impedance mismatch was of a reactive or resistive nature. Not only would the sending unit have to deal with the reflections playing games with the output section, signal loss is increased. The resultant decline in detail is increased due to loading via the "back-pressure" within the transmission line. This is not to mention that line loss increases as VSWR increases, compounding the factors involved drastically. As such, ANY type of vswr / signal reflections tend to start a very drastic downward spiral effect once they come into play. This is FAR more apparent with SS gear, but then again, i don't know of any transport or CD player that uses a tubed digital output section.

As such, i would think that all of my experience with RF loading characteristics and impedance mismatches would directly apply to digital data transfer. I would suspect that the output section of most transports / cd players would not be very stable due to lack of a buffer circuit or complex impedance matching network. Therefore, ANY gains in terms of increased power transfer / minimization of reflections would be of multi-fold benefit for the aforementioned reasons. I have not verified this personally, but see no reason why this would differ from any other RF based SS circuit loading up. I really do want to start measuring and experimenting in these areas, but just have not had the time to do so. Sean
>

Sean,

I can tell you there is an 80-90% chance that the
last reply you sent went thru a OC192 backbone router that is running at 10ghz and the 10% mismatch rule applied to that product too and it works real good. We have to allow for material caused mismatches.. PCB fabrication is a major
contributor as is cable construction.

Sorry if im overstating the odvious BUT Its a fact of life...mismatches will always be there just like taxes.

Taxes are not "mandatory", nor are "mismatches" and "reflections". The more that one becomes familiar with and "works" the system, the less of each they may have to deal with. If one is really good and / or dedicated, it is possible to reduce any of the above to a point of negligence. Just because they are there does not mean that they should be "accepted".

Such is the case for signal reflection and vswr within a system. Why settle for 90% efficiency when one can have 99 - 100% ? The only difference is how much effort and money one is willing to invest to achieve that 10% improvement? When dealing with mass manufactured products, it is probably good enough. When dealing with small quantities of "high tech" products ( such as "high end" audio ), that is too much "waste" as far as i'm concerned. "Settling for" mediocrity or what is "good enough" never made me happy. Sean
>

Sean,

I need to talk to your tax guy :-)

I agree with you 100% its all about the benjamins$$$
I never said i like mismatches... Why do you think i
spent big bucks on my cables... But there are still
other problems on the chain and unless you youself
are designing AND fabricating the product including
the transistors you are at the mercy of ACCEPTABLE
tolerances. Welcome to the real world.. I dont like
it either BUT its reality.

Maybe you can explain to me how to get better impedance
control than what the fab houses can fabricate the product
for? In other words we design these "low tech" 48 layer
10 thousand connection PCB's running at 10ghz and 50 ohms dead nuts on... Its like having 10 thousand interconnects in a 5 sq foot area... What are we gonna do have kimber cable wire us up something?
We are forced to rely on material and fabrication tolerances. There are only two board houses IN THE WORLD that can fab that PCB for that"low tech" backbone router.

How would you do it?

I would probably have to agree with the possible theory that differences in cable geometry(or connections) will cause differences in the delicate structure of sound to different degrees.(my theory..and only a theory). I DO FIND that cables sound very very different often, and DO AFFECT THE SOUND MORE DRAMATICALLY IN BETTER MORE RESOLVED SYSTEMS for sure. I am indeed a believer, from working in 5 high end stores, and being around high end audio and custom install for more than 20 years now, that cables make a difference!
I also find that the trend amoung those advocates that cables ALL BASICALLY SOUND THE SAME(if matched from a mechanical impedance standpoint, etc), THEIR SYSTEMS TEND TO ALL SOUND POOR OVERALL!!!
I once had a long conversation with John Dunlavy(Thanks john for the contributions to audio) at his factory about cables. He is an advocate that "CABLES IS CABLES" basically. The irony there is that his systems in his factory where, HANDS DOWN, the single WORST SOUNDING set-up's I've ever heard from a "HIGHER END" speaker manufacturer!!!! Infact, other people touring the factory were asking me why his speakers sounded so bad....I litterally had to defend his speaker's "merits", and say that "I'd gotten much better sound from his speakers elsewhere!"
On another occasion, I was at CES in Vegas a year ago, where I stumbled in to a room set up with Merlin VSM's with some nice high end gear. I asked the guy running the room "what wires and cables are you using?" He actually looked at me and said "you're joking right?"..."surely you don't think cables make a differnce, do you?" I said, "no comment!" I proceeded to listen to the set-up when he started playing the music, and IMMEDIATELY BOLTED UP FROM MY CHAIR!!! Not only did I hear the most bright and analytically sound from any of the rooms I encountered during the trip, but everyone else in the room immediately took issue with the sound as well! I didn't even stop to say anything to him...I think he pondered it all on his own from that point out.
My experiences, basically, is that the "cables-is-cables" advocates, are usually "closed-in" with their thinking, and can't see past their brains!!(limited processor and hardrive I presume...) These are the one's I usually find have the poorest sounding, if even well intentioned, systems!..go figure

Spluta: I was primarily refering to audio and low frequency RF gear. When you start hitting high frequency RF, you can have it. Things can get WAY "squirelly" REAL fast. I can understand that you have to take what you can get in situations like that, as there just aren't a lot of alternatives out there.

Foreverhifi: Out of curiosity, what was Dunlavy running for electronics at their factory ? I would assume that he had his Z-6 speaker cables, but do you know what was used to connect all of the gear ?

This brings up another topic. If the gear / speakers being used within a manufacturer's reference system sounds like "hell" and / or is set up poorly, how is it that they can really tell if something sounds "better" or if they have actually made an improvement to a product during listening tests ??? This is not to pick on John Dunlavy in specific, as i surely respect him for his knowledge and experience. Sean
>

Sean,

Can i still have your tax guys number? just kidding.
I agree...audio and high speed are two different worlds
and I do get them confused sometimes...

Forever,

I think you brought up some very good points. The more
i think about it the more im thinking perfect length
of wires might not be ideal for audio. Hmmm.. So what do
you say guys lets sell different lenght MATCHED cables
and get rich?

Best regards

forever, are you saying the reason the systems you site as sounding lousy was because of the attitudes of the owners, or that they chose bad cables? I douby in either case they were using lamp cord

steve.

I am not well read on auditory theory, but I seem to remember reading somewhere that auditory memory is good for a few seconds at most. Also that non-blind tests are statistically worthless since visual clues, foreknowledge and so forth demonstrably invalidate the test. Also, that expectation ("I am now changing the cable") leads to perceived differences in sound (even when the cable is not actually changed). Or do we dismiss this overwhleming scientific evidence under the illogical rubric that music is so very complex and objective undestanding so very limited that subjective experience outweighs it, and hence cables must make a difference?

"Yes" is the short answer. I don't necessarily agree, but that seems to be the point of view of this community.

I'm jumping into this late but here goes.

First, don't assume that people who can't hear the difference in digital cables have a bad system or bad ears. Maybe they are just fortunate that their system components match well enough that the cable isn't much of an issue. Having a system that is very sensitive to cable changes may not always be such a good thing.

Second, I've tested a few ADC's (similar to DAC's) and clock jitter is extremely important in reducing harmonic distortion at audio accuracy levels. As mentioned above, errors in the time position of the sine wave samples will distort the sine wave, just as voltage errors will.

What we're talking about is two issues: data recovery from a serial bit stream and also clock recovery from the same serial bit stream.

Although data bits errors should be rare in a well-designed and well-matched system, they will cause serious problems when they occur. As noted above, there is no error detection or recovery mechanism for data errors. All serial data transmission schemes will miss data occasionally and the measure of that is the "bit-error rate".

Clock recovery circuit design is almost an art. I'm not familiar with the CD standards. I assume that the DAC's clock recovery circuit uses a PLL. Is this correct? The PLL will filter out alot of the high frequency jitter. Better PLL designs will filter out more jitter.

We have equipment to measure jitter where I work. The accuracy is in tens of picosends. The inputs are all 50 ohm. This equpment should be usable for testing the transport/cable jitter. Does anyone have ideas for some easy experiments using this equipment? It might be interesting to measure several types of transports.

Leme@lone.com
No actually you'd be wrong!...I swear!!!
In one of John's (Dunlavy's)systems, HE WAS USING LAMP CORD FOR THE SPEAKER CABLES!!!!(all-be-it 12awg).
Now don't get me wrong, I think the gear he was using was not so good either. Infact the refernce system, which used SCIV's, had Marantz MA500 mono blocks, and a digital Marantz pre/pro up front!!...OH THE GLORY OF SOUND!!!! Patch cord IC's, Lamp cord for speaker wire, mid-fi(at best) gear...I couldn't believe what I was seeing/hearing!
He believed(JD) that a good amp was a good amp, and all wire was the same if it measure(with his test equipment) proper impedence/inductance/capacitance or whatever, it HAS TO SOUND THE SAME he stated! Infact, he went on to often say that "God himself couldn't hear the difference in two wires/cables measuring the same values!!!!! Ehem......

Does anyone know where i can find some THX certified
lamp cords?

Foreverhifi: I might agree with John Dunlavy regarding his comments "God himself couldn't hear the difference in two wires/cables measuring the same values!"

If the cables presented identical loads to the source component with the same level of signal transfer into the load component, they "should" sound identical. However, it would be possible to measure cables and have them come up the same yet be electrically VERY different from one another.

One could use a cable constructed like Kimber 8TC and insert inductors in each leg of the run and then take a run of 10 gauge zip cord and insert capacitors in each leg of the run. The total resistance, inductance, capacitance and impedance for both cables may measure the same on a meter but the fact that some components were lumped and others were evenly distributed would cause current to flow VERY differently along the length of the lines. As such, "tuned networks" within a small area may not be as effective as achieving similar electrical characteristics over a wider spread and vice-versa. Much of this will depend on what you are trying to achieve and the rest of the circumstances involved. Whether or not we can actually hear such things is a good question and one that i would love to be able to know ( and prove ).

As to the cables that Dunlavy was using, i would have thought that he would have been using some of his own speaker cables and interconnects. As to his choice of gain stages, he should have known better than to say that "an amp is an amp" etc... He used to design and market components back in the 1970's and they were very well thought out in terms of circuitry. I don't know how well they were constructed or if he paid attention to parts selection, but he knew enough to try and design something that was "technically correct" to say the least. He is a very smart guy but whether or not he applied everything that he knew at all times is another matter. Sean
>

Simply look at how many digital cables are being sold and bought daily on Audiogon, and all you will know if digital cables makes any difference with sound reproduction. Don't tell me that the 100-200 idiots buying the cables are real idiots! There gotta be reasons. Cable design minimize signal loss and interference, this theory apply on kinds of cables! I used a 2M XLO Digital Cable instead a 1M one day, and I noticed the difference. Its the same model, same spec. same measurement, why did it sound different? You all tell me...

Impeadance matching is the most important factor.
This is going to get a little tekkie, so hang on.
It does not matter if the signal is analog or digital, the higher the frequency, the more important impeadance matching becomes. At RF, when a signal encounteres an impeadance mismatch, the signal is replected baclk up the line. The more the mismatch, the larger the reflection, and the higher the frequency, the greater the reflection. The specification for SP/DIF is for a 75 ohm impeadance. This means you need to use 75 ohm cable AND 75 ohm connectors. Well folks, most RCA connectors are NOT impeadance matched. The one big exception is Canare, which makes precision 75 ohm crimp on connectors for a very reasonable price.
Canare has premade 75 ohm cables available, and there are several people out there rolling good 75 ohm cables using Belden 1694A or 1695A with the Canare connectors, typically between $20 and $30.
For the best results, use BNC instead of RCA connectors. The BNC was designed to be an RF connector, and though originally designed to be a 50 ohm connector, there are 75 ohm available, such as Canare. The problem is that only the really good high end equipment usually comes with BNC's as an option, so the modestly priced CD or DVD you want to team up with a good DAC is not going to come with BNC's available.
I am not saying whether other factors, such as silver vs copper, or teflon vs. pe affect sound quality, but I am saying that if you are not impeadance matched, all the other cable snake oil will not matter.

Expensive Digital cables sound different because you sit lower in your chair when listening to them. This is because your wallet is empty.

I still think a more interesting question is: Why do AC cables sound so different? or Why do AC cords make such an impact on a systems sound?

The AC cord seems much more mysterious to me because it does not directly carry the audio signal at all in a system.

I posed this question and there were only 6 responses at:

http://forum.audiogon.com/cgi-bin/fr.pl?fcabl&1042221110&openusid&zzTok20000&4&5#Tok20000

KF

here's what you need to do... go to your local wal-mart and purchase you a GOLD-PLATED OPTICAL cable, THAT'S WHERE IT'S AT!!!!! HA HA HA. (believe me, they make 'em)

I want a DAC with a slot for PC133 SDRAM, a 5 1/4 drive bay and an IDE controller. Those features should cost less than $60 retail (motherboards do that and a lot more for $60). I'll drop in 128 megs of RAM from crucial for $35. I'll plug in a 40x Plexwriter for $90 with a $3 IDE cable. Then the DAC can expect 100% accurate data to pour into the buffer at several times the playback speed. All it needs to do is pull out samples every 1/44100th of a second and do its thing with them.

If you think streaming bits from a buffer is somehow inferior to streaming them from an external component... well, uh... good for you, I guess. I hear that buffing bits smoothes them over and takes the harshness off the music, but to each his own.

Seriously, if $300 digital cables make a difference, we need to demand better hardware, plain a simple.

This discussion died off. Why?
I'm in the "I can hear a difference and I don't know why" camp between Coax/RCA terminated cables. Some expensive digital cables sound better than the HAVE Canare, some sound worse. I dunno.

I have noticed that there ARE differences, but that they do not seem to correspond to price, etc.

Fiber optic, IMO, is the best, and the cleaner the optics, the less distorted the signal , so theory would go.

But I do notice that, even my $20 Monster Toslink outperforms my $200 "digital" coaxial cable.

The cheif designer of Musical Fidelity products swears that ANY transport will do when using digital links to the DAC! I am not an expert, but I did notice that my Panasonic DVD player soundes better using the Toslink than my Rotel does via the coax digital. This is odd, since the Panasonic set me back around $70.00, and the Rotel about $450...USED!

In Rotel's defense, however, I simply LOVE their DAC (RDP 980). I have compared it to a few others consting WAAAY more, and the Rotel seems to hold its own NO PROBLEMS!

Water dripping sounds, drum beats/cymbal decays, and plucked strings are all quite remarkable via the Rotel DAC.

Mickey Hart, "Planet Drum" and Bela Fleck "Live Art" are two of my fave discs to show-off my Hi Fi system.

Bela Fleck "Perpetual Motion" is another great disc, and I can hear subtle differences between interconnects SIMPLY by listening to Fleck's fingers slide up and down the banjo strings.

Even the cheapest fiber optic cables reveal THREE times more detail than the coaxes, in my system...

your mileage may vary.

Joe M.

Here is my digital cable upgrade path over last 3yrs, getting slightly better sound each step at lower prices:

AZ Mc2 $300 --> WW Supernova III glass toslink $100 --> Sonicwave glass toslink (280 fibers) $25 --> Stereovox HDVX $100 currently used.

Still have my $25 glass toslinks around one of best examples of "bang for the buck" ever in my cable buying experience.

Over spring break, I had a chance to listen to my Rotel/coax vs. my Panasonic/optical.

The first impression was one of much more oppeness, and a deeper sound around instruments with the optical output.

*HOWEVER*, cymbal crashes, esses, fingered strings, etc all sound FAR better via the coax!

For highly digital source material, like "The Matrix," the optic input adds a nice effect, making everything "feel" digital. It also seems to portray a tad mote bass (but it actually just muddies it up, when compared a/b).

I used my own, and a friend's copy of the Rolling Stone's "Love You Live" disc, and could simply switch between the two units on my Rotel DAC. The crowd sounds bigger, the clapping more real, and the music more convincing via the coax.

I'll admit I was hasty the first time I posted, and I'll think twice, er, listen twice before running my mouth next time!

I was one of the original people to post on this topic, almost 3.5 years ago. My position, that any "properly constructed" digital cable should be indistinguishable from another was predictably met with scorn and ridicule. My ears and even my choice of a mate were questioned. Not that the later has much to do with the topic. Unfortunately, some people when confronted with someone else’s views that don’t agree with their own can’t stay objective.

While I still hold my beliefs, let’s look at some of the other factors that might be in play.

Joemazzaglia makes the point that when he heard optical fiber and coax cable through the same unit, there was a big difference, in favor of the coax. I believe that he heard that difference and it is not surprising. A number of manufactures warned that maximum fidelity could not be obtained from the Toslink connections using their equipment. I believe that is because they hadn’t optimized for optical digital transfer.

There is also the issue of true optical glass cable, vs. plastic. I’ve purchased some true optical glass cables and their performance clearly exceeds a cheap plastic one I bought as a comparison.

I would be interested in whether Joemazzaglia would notice the same difference
if two or three coax cables, all true 75 ohm and made by reputable manufacturers were compared in a blind test? That would say more about the cables, since they are of the same type.

My own experience with a very fine DAC the Levinson 30.6, which has coax (SPDIF), balanced (AES/EBU), as well as Toslink inputs is that the type of cable shouldn't matter. I have compared AES/EBU digital cables from Cardas and Madrigal, with SPDIF cables from Kimber and Madrigal and true Corning fiber optic cables through the Levinson and have not be able to detect any noticeable differences. (The cheap plastic cable notwithstanding)

While none of these cables was a bargain basement item. They are also not cost is no object (or maybe cost is the only object) designs. They are all good well engineered and manufactured products that do exactly what they claim to which is move digital data from one component, the transport, to the next, the D to A converter. They do so properly and predictably and the DAC then can produce the analog signal it was designed to.

I think people need to remember, digital cables transmit 1’s and 0’s. They don’t transmit anything that a speaker would make into sound. That all happens after the DAC converts the signal to analog.

Also, my argument wasn't that any piece of copper wire from Radio Shack will do as a digital cable. I was pointing out that once a design has "got it right", which can be achieved as fairly moderate cost, “Gilding the Lilly” by adding meaningless features (super fancy connectors, braiding around the insulation come to mind) that add cost but change nothing about performance doesn't make the sound better.

I also understand that pride of ownership may make us prefer the fancier cable and if that is so and we can afford it, go for it. But don't try to convince ourselves or others that the sound it can produce changed.

I know that will probably start another round of name calling and if so, so be it. We have a right to our opinions, but I find it discouraging that people attack when confronted with ideas that they don't want to accept. Also too much is made of too little in this hobby. I hate to see folks be convinced that they can buy something that isn’t there if they just spend more money.

Check out bryston's website.They have a simple yet accurate response to your question...

As there are in power cords great differences are to be heard in digital cables..Much to do about time and phase coherency. Tom

Unlike other areas in cable design that are questionable to say the least there are actually scientific reasons why digital cables have to be correctly designed.So unlike power cords differences actually can exist in digital cables...

For sake of clarity, i am not Sean125. I didn't want anyone to confuse my departure with his arrival. Given our different points of view on power cords, it should be obvious that we aren't one and the same. Toodles... Sean
>

Sean, "departure"? What did I miss?

I use the i2s stock cable.Would upgrading this type of cable help my Dac & Transport sound better? If so, HOW? Are silver conductors better then copper for this type?

I have a question for the engineers here. When playing around with cables I found something odd. Let me give you an example. If I used a particular belden cable design, albeit in different guages, using all teflon insulation and silver coated copper, I found a consistent flavour to these cables regardless of their application. You will have to trust me that I verified this with some blind testing, but once I recognised the flavour I could always hear when one was inserted into the system. This happened whether a fat one was used for a power cable, or a speaker cable, or a thinner one was used as an audio interconnect or a digital interconnect. I am not saying I didn't hear other things about these cables, but I am saying that there was a consistent additive quality, perhaps some form of ringing, regardless of the application of the particular type of cable.

I recently added such a cable to power a CD player that was connected to the system I was listening to but was not the source I was listening to and immediately heard its sonic signature. I was not expecting to hear it, and was stunned to hear it, so I don't think the issue was psychologically induced.

So other than me being mad (which is a whole 'nother question), is it possible that any cable connected to a system is an antenna of some sort and introduces audible effects even when used as a digital cable, provided there is some analogue component that is electrically connected in some way to that cable?

Red: I've heard very similar sonic traits when using certain analogue cables as digital cables. Since the impedances between transport to DAC would normally be very different from DAC to preamp, another line level source to preamp or preamp to amp, i don't know why this is. Having said that, some folks that i've talked to that have cables built to their spec insist that every manufacturer introduces their own sonic signature into what they make. That is, the grade of copper or silver, how the wire is formed or drawn, etc... all plays a key in the sonic signature. As such, some folks have had cabling made to the same spec by several different manufacturers and they all sound different. This is the kind of stuff that boggles the mind yet would probably reveal quite a bit if someone were willing to devote the time to research the subject. Then again, maybe that's why "audiophile" cables cost so much i.e. we have to pay for all of the R&D that's taking place : ) Sean
>

The trick is the overshooting or undershooting from the digital transformer,this combine the different of capacitance of so call digital cable to trim different sound,and as well as Q factor of sampling frequency..

Red - I think you're mad actually, just kidding....

I have no explanation other than the usual parametrics, R,L,C and dielectric absorption. Also, dont forget metallurgy.

One thing that I didn't mention before was the length/speed effect that I explain in this paper I wrote for Positive-feedback:

http://www.positive-feedback.com/Issue14/spdif.htm

ading - What engineering school did you go to????? Ive never heard such drivel....

Spluta wrote:
"From what ive seen there is a major flaw in the spec itself The #1 contributer of EMI is the rise time. The quicker it is, the more EMI emitted. A common misconception is the Freq is the culprit not true. Its seems to me that the rise times are faster than needed for the application.

Not true at all. The risetimes are purposely slowed in 99% of transports in order to pass FCC and CISPR. This actually contributes to jitter. If the terminations and impedances are matched, there will be very little EMI, even with very high edge-rates. Please read my PFonline paper.

end of msg.

Just because the current state of engineering science (which, in the digital audio sphere, is still relatively young)cannot adequately explain why digital cables might sound different from each other does not mean they do not. I have experimented with at least 7 or 8 digital cables, from the Illuminati D-6 all the way up to Kharma and PAD Dominus and they all have sounded distinctly different to me in A-B comparisons, with some audibly better than others to a significant degree. I did not imagine these differences; they are there and I hear them, as do others listening along with me. Rememember, it was not too many years ago that people were asking the same question about power cables: Why should they make a difference, they are just carrying electrons?

As Hamlet said: "There are more things on heaven and earth, dear Horatio, than are dreamt of in your philosphies."

Bottom line: I think they make almost as much difference as interconnects. I wish they didn't (one less variable to deal with)but they do.

One man's humble opinion after over 30 years of dabbling in this mania.

Neal

When can this issue go to the scrap heap of history?

If all this is true, how come that the Purist balance digital cable between my cd and dac sounds different than the Nordost digital cable in a direct swap?

I still dont understand what is the point in having a 75ohm cable when the input and output impedences of the components are not really 75ohm. Unlike pro equipment which seem to be true 75ohm with a transform termination. I do not see any transformer termination in consumer and even some high end equipment. Is it possible to have 75ohm impedence without transformer ?
I do agree that digital cables make a difference and jitter is the culprit.