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I intend to connect my DVD player to Receiver via digital output.. which of the a/m should I get? Any recommendation?

 

Best choice is to use digital coaxial interconnects.

 

For a good budget buy will be custom-made using Belden 1694A with Canare 75-ohm connectors.

 

Tested this to sound much better on the same setup when using the analog "Yellow" RCA cable which is bundled when U buy a VCR or VCD or DVD player.

 

If U have more cash to burn, there r even better cables from Belden.

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If going by digital co-axial, I recommend 1694a cables.

 

Remember to keep the cable as short as possible. Don't exceed 2m when using such cables otherwise sound quality will degrade.

 

Rationale is coz digital data becomes more and more distorted as distance increased. Analog signals also face this problem but at a less sever degree.

 

Optical is a good alternative.

 

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I have a friend who sends me 2m+ optical cables from UK.

 

Anyway, digital co-ax more than 2m is no prob, just that you can start to hear the diff between 2m coax and o.5m coax

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If going by digital co-axial, I recommend 1694a cables.

 

Remember to keep the cable as short as possible. Don't exceed 2m when using such cables otherwise sound quality will degrade.

 

Rationale is coz digital data becomes more and more distorted as distance increased. Analog signals also face this problem but at a less sever degree.

 

Optical is a good alternative.

 

 

I've belden 1695A with Canare termination as my component video cable.. can I safely say that I can use this cable as digital interconnect?

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If going by digital co-axial, I recommend 1694a cables.

 

Remember to keep the cable as short as possible. Don't exceed 2m when using such cables otherwise sound quality will degrade.

 

Rationale is coz digital data becomes more and more distorted as distance increased. Analog signals also face this problem but at a less sever degree.

 

Optical is a good alternative.

 

 

I've belden 1695A with Canare termination as my component video cable.. can I safely say that I can use this cable as digital interconnect?

 

You should be able to do so.

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There are the monster cables and the other more expensive cables.

 

Althou, more expensive does not necessarily translate to better performance.

 

Logically, I wouldn't use those, esp for short distances. Give all cables a blind test with an open-mind.

 

 

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I intend to connect my DVD player to Receiver via digital output.. which of the a/m should I get? Any recommendation?

 

 

If U have more cash to burn, there r even better cables from Belden.

 

pcking,

 

Could u tell us those cables better than 1694a? I'll love to give them a try and subsequently post my views.

 

I only find the 7731a/7732a cables better, but very hard to work with.

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Personally, I do not like the end result of Belden when used as a digital audio cable (they are fine for video however). Tried 1694A, 7731A, 9259, 1523A and a few others. Of the lot mentioned, like 1523A the most but my own favourite, irrespective of price, is Mogami 2964 terminated with Neutrik ProFi RCA plugs.

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Personally, I do not like the end result of Belden when used as a digital audio cable (they are fine for video however). Tried 1694A, 7731A, 9259, 1523A and a few others. Of the lot mentioned, like 1523A the most but my own favourite, irrespective of price, is Mogami 2964 terminated with Neutrik ProFi RCA plugs.

 

Is Mogami 2964 stiff cable? I find belden 1695A too stiff... I bought a QED Qunex P75 at S$28/m and terminated by Audio Act with RCA plug for additional S$10..will try it this weekend..

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Mogami 2964 is very flexible and that's the beauty of it. It is also very detailed, with lots of micro details but not as exciting as say Belden 1523A which has more slam. Belden has too many models and to select the best one is a headache. Also performance and price have no correlation. Belden 1523A is one of the cheapest I have tried, but also the most preferred where digital audio is concerned.

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Just a sideline. I'm really skeptical to spend too much

money on a digital cable. Then again, I'm a newbie.

 

A question:

why is it so difficult to transmit a perfect signal over

an AV setup as compared to traditional computer

network? Interference? Real-time requirement?

 

I'm really amazed that a digital cable can make

so much difference. And "breaking" in digital cable

sounds even magical!

 

Digital signals are merely "1" and "0", and the quality degrades when a "1" arrives

as "0" or vice versa. If I'm not wrong, most transmission

protocol has error correction mechanism,

which should at least be able to correct or

detect (retransmit) around 5% error.

 

For comparison, I'm using a cheapo network cable

that is able to transmit 100 Megabits per second

with PERFECT data integrity ( ), over a distance over

2 meters. And that is an old technology. ( going to

Gigabits now ). And if you're talking about

interference, just take a look at a network switch.

It typically has > 30 cables close to each other.

 

What I REALLY WISH is a receiver that can tell you

the error rate. That'll eliminate all the guessing

game. If error rate is Zero for a particular cable

then that cable is enough.

 

btw, dun even bother to mention "breaking-in" to a

network engineer.

 

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Just a sideline. I'm really skeptical to spend too much

money on a digital cable. Then again, I'm a newbie.

 

A question:

why is it so difficult to transmit a perfect signal over

an AV setup as compared to traditional computer

network? Interference? Real-time requirement?

 

I'm really amazed that a digital cable can make

so much difference. And "breaking" in digital cable

sounds even magical!

 

Digital signals are merely "1" and "0", and the quality degrades when a "1" arrives

as "0" or vice versa. If I'm not wrong, most transmission

protocol has error correction mechanism,

which should at least be able to correct or

detect (retransmit) around 5% error.

 

For comparison, I'm using a cheapo network cable

that is able to transmit 100 Megabits per second

with PERFECT data integrity ( ), over a distance over

2 meters. And that is an old technology. ( going to

Gigabits now ). And if you're talking about

interference, just take a look at a network switch.

It typically has > 30 cables close to each other.

 

btw, dun even bother to mention "breaking-in" to

network engineer.

 

 

Maybe this article can help. :)

 

A very common misconception about digital signal

transmission with respect to audio is that if the signal does

not get corrupted to the point of losing or changing the 1's

and 0's, that nothing else can go wrong. If the transmission

system had been designed with cost no object, and by

engineers familiar with all the known foibles and problems

of digital transmission of audio signals, then this might

be subtantially true. No differences could rear their ugly

head.

 

Unfortunately, the systems we ended up with DO NOT remain

unaffected by such things as jitter, where the transistion

from a 1 to a 0 is modulated with respect to time. There are

many ways that jitter can affect the final digtial to analog

conversion at the DAC. Jitter on the transmitted signal can

bleed or feed through the input reciever, and affect the DAC.

How? Current drain on the power supplies due to the changing

signal content and the varying demands made on the power

supply to the logic chips and the DAC. Modulate the power

supply rails, and the DAC will convert at slightly different

times. This is due to the fact that a logical one or zero is detected by the signal swinging through a regoin from around zero volts to around 5 volts. The digital logic chips detect the change at a specific PERCENTAGE of that total voltage swing.

 

HOWEVER the power supply gets modulated, it will

affect the DAC. One version of this has been popularly

refered to as LIM or Logic Induced Modulation by the

audiophile press. See:

"Time Distortions Within Digital Audio Equipment Due to Integrated Circuit Logic Induced Modulation Products"

AES Preprint Number: 3105 Convention: 91 1991-10

Authors: Edmund Meitner & Robert Gendron

 

Many of the logic chips in a digital audio system behave

very poorly with respect to dumping garbage onto the rails

and even worse, onto the ground reference point. Even as I

post, logic manufacturers such as TI are advertising the

benefits of their latest generation of logic chips that

reduce ground bounce. The circuitry itself generates it's

own interference, and this can be modulated by almost

anything that also affects the power supply or ground.

 

The amount of jitter that it takes to affect the analog

output of the signal used to be thought of as fairly high,

somewhere on the order of 1,000 to 500 pS worth. Now, the

engineers on the cutting edge claim that in order for jitter

to be inaudible and not affect the sound of the signal, it

may have to be as low as 10 to 20 pS. That's for 16 bit

digital audio. That's a very tiny amount of jitter, and

easily below what most all current equipment is capable of.

 

Computer systems never convert the 1's and 0's to time

sensitive analog data, they only need to recover the 1's

or 0's, any timing accuracy only has to preserve the bits,

not how accurately they arrive or are delivered. So in this

regard, computer systems ARE completely different than

digital audio systems.

 

Look into digital audio more thouroughly, and realize that

the implementations are not perfect or ideal, and are

sensitive to outside influences. Just because they could

have been and should have been done better or more nearly

perfect does not mean they were! People are not hearing

things, they are experiencing the result of products designed

to a cost point that perform the way they do in a real

world because of design limitations imposed by the consumer

market price conciousness all the mid-fi companies live and

die by.

 

With digital cables, there are three things that are paramount:

proper impedance, proper cable termination, and wide bandwidth.

It may be that a particular cable more nearly matches a systems

actual impedance. The other factor, proper termination includes,

but is not limited to, the actual electrical termination inside

the components, as well as the connector on the end of the

cable. If the connector is NOT a perfect 75 ohm, 110 ohm, or

whatever, it will cause minor reflections in the cable, which

makes our old friend JITTER raise it's ugly head again.

 

The third factor, bandwidth, is only an issue because both the

AES/EBU and the SP/DIF interface formats were designed before

Sony/Phillips knew all there was to know about digital problems,

and they require PERFECT unlimited bandwidth cables in order for

the transimission systems to be free of jitter. The more you limit

the bandwidth, the more jitter. This is a known engineering

fact, and an AES paper was given about this very subject not

too long ago.

 

"Is the AES/EBU/SPDIF Digital Audio Interface Flawed?"

AES Preprint Number:3360 Convention: 93 1992-10,

Authors: Chris Dunn & Malcolm O. J. Hawksford

 

The effective data rate of SP/DIF is about 3 Mhz, and the

design of the transmitters and recievers is abysmal. Maybe

if everything else was done right, then cables, etc. wouldn't

matter. So much was done wrong or cost cut till it screwed

up that they do come into the picture.

 

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Thanks Pcking for the interesting article.

enlightened. ;)

 

Maybe some enterprising enginner/students would

like to take up the challenge. :)

 

Some comments:

1. What would be really useful is for the receiver

to report the error rate. When it reaches zero,

we'll have the perfect cable for the current setup.

No guess work.

 

2. All form of jittering can be eliminated/minimize by using buffering which is OK for music. ( not so for movie

coz picture and sound must sync). Anyhow,

jittering cause by poor IC design remains, even

with the best digital cable in the universe.

 

3. The most ambitious project is to come up with

a proper coding and buffering mechanism for both

music and video.

 

Sorry for the interruption, we should go back

to discussing which cable is better in this imperfect

AV world.

 

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[quote author=Jag

 

pcking,

 

Could u tell us those cables better than 1694a? I'll love to give them a try and subsequently post my views.

 

I only find the 7731a/7732a cables better, but very hard to work with.

 

I was refering to the 7731A & 1695A. After trying out the three including the 1694A, I still find the 1695A sounded a little better.

 

Actually U have replied to me before that the technical specs of 1695A is actually slightly lower than 1694A & the reason for the high price for 1695A is due to Plenum Rated over the 1694A. So theoractically, 1694A should sound better.

 

But after testing all the cables out (all in 1 meter run), I rate them in this order.

1) 1695A

2) 7731A

3) 1694A

 

It was unbelieveable & I was wondering how come ???

 

After much reading thru' the net, I found out that maybe its due to the jacket material. PVC is the worst jacket an audio interconnect cable should have. The 1694A & 7731A are having PVC jackets. The 1695A is having the Flamarrest jacket which is considered as the borderline jacket.

 

Cut & paste from a website"

-Jacket Materials-

In descending order of preference:

Solid Teflon (TFE)

Solid FEP Teflon

Fluorocopolymer

Silicone Rubber

 

Borderline:

EPDM

Flamarrest \

Rubber These three are real close

Neoprene /

 

NOT RECOMMENDED FOR SERIOUS AUDIO USE AT ALL:

PVC (Polyvinylchoride)

Polyurethane

 

But in terms of cost/performance ratio, I still find the 1694A is the best budget buy.

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Personally I find that belden cables need quite some time to "burn-in" before the actual quality "kicks" in.

 

Another thing which I feel is: a good cable for digital coaxial audio interconnect is not likely to be as good when used as an analog interconnect audio cable.

 

Any comments on the above ?

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Ah,... a few items of misconception.

 

1) I'm not sure which article this was cut & pasted from, but its not the jacket material, but the dielectric material of the insulator btw the conductor and shield.

 

The idea is that perdendicular lines of electric fields exist between the conductor and shield. Telfon allows less signal distortion in terms of E-field in comparison to other dielectic materials. The ideal dielectric material has got excellent electric field charactersitics. Teflon

 

Telfon or PTFE (Polytetraflorethene) has got a different dielectric constant as with others, so it interacts with the signal differently. Ideally, the dielectric should have a dielectric constant value close to 1, which is air. Teflon has dielectric value = 2. 1694a foamed polyethylene dielectric is 1.64.

 

If we actually looked into the structure of the Co-ax cable, the centre conductor is surrounded by a dielectic insulator followed by the shield then lastly by the jacket. The jacket does not affect the electromagnetic behaviour of the cable. Its the shield coverage, the dielectric material and the stranding and type of the centre conductor since they are the active EM elements in signal propagation. You could say the coax has got parastic capacitance, attenuating higher frequency components more than low frequency components.

 

So, the attention paid to the jacket is least important relatively. More importantly, the dielectric, shield coverage and centre conductor material is more improtant.

 

2) Digital interconnect is not really different from analog interconnect. The main reason: the unique audio re-production system each individual has. Everyone has got a different system from everyone else. An analog interconnect sounding better in pcking's system may not neccesarily sound better in fourier system.

 

It can be very subjective on which cables sound better. The 1694a can sound smoother and less harsh than a silver inteconnect. Thus, it may sound better on a forward-sounding system, and worse on a laid-back system. The audiophile industry has largely forgotten about the mechanics of cable selection.

 

Its best to at least understand the cable characteristics. find out about the cable design. Is it silver coated, silver coated copper? The length of the cable? The type of connectors used?

 

Logically, digital cables would be the best analog interconnect. But in most audiophile circles, its not true. Why? Coz audiophiles don't believe in tone control. Instead, they use cables as a sort of tone control. Haha,....its like colouring an otherwise uncoloured interconnect. Again, silver coated interconnects would sound brighter than a 100% copper interconnect. Along the same line, a thinner interconnect would sound more laid back than a thicker one of the same specs.

 

So technically, a digital interconnect would make the best analog interconnect. However, due to extreme bandwidth available on digital interconnects, they may sound too "clinical" or harsh. To counteract this harshness, an "analog" i/c would colour an otherwise wideband digital cable.

 

3) The length of the cable counts. The longer the i/c, the worse the quality of the sound. Reason is due to group delay. Lower frequency components will travel at a different speed than higher freq components. This would not make a difference to analog interconnects, but it will wreck havoc with digital signals. Nvr use analog interconnects for digital use.

 

4)The connectors used. Please use proper termination techniques for digital cables. Impedance mismatches would cause reflections and cause phase difference and constructive/destructive summing. For analog cables, the same goes. however, its a matter of maximum power transfer.

 

5) Jitter or phase noise is a big problem in todays digital systems. Digital systems have intolerance to jitter. Else, all the data would be wrong since digital data depends ver much on the regularity of the signal. For unbuffered systems, this is very important, e.g. PCM audio. Buffered data like DD/DTS is less important. However, its not so simple, since jitter comes about due to modulation of the local oscillator.

 

I would still say that the best cable does not exist.

 

The ideal cable exists thou, based on the audio re-production system.

 

One thing still stands out like a sore thumb: Audiophiles don't believe tone controls, but they believe in cables doing the tone control for them. Ironic, but true, although most audiophiles won't admit it.

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yeah,... the chain is only as strong as the weakest link.

 

A mellow cable will tame bright sytems, but bright cables will wreck havoc.

 

Burning in cables is a time process.I'm sure its a combination of the magnetic alignment of electrons, the EM interaction of the conductor, dielectric and shield, and the eventual oxidation of the copper/silver conductor.

 

Best way to burn in cables? Use them..... Just like the best way to season shoes is to wear them. ;)

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