A stereo shop tried to sell me a better quality fiber optic cable, I don't
remember brand names or anything, they claimed better sound quality. The
regular cords were $20 to $30.00 and the good one was $70.00 Canadian
dollars. Do the people of this group fell it makes a difference what
TOSLINK cord you use. I thought all it had to do was pass on a digital
signal. What about digital coax.?

thanks,

Colin

Truth be told, I don't get it. A few years back, I bought an
external DAC, and needed a cable to run from the digital out of
my CD player to the DAC. Both TOSLINK and Coax where options.

I did a bit of research, and discovered that the golden ears of
audio (Stereophile, TAS) find digital Coax superior to TOSLINK,
without exception. In fact, Stereophile does not include TOSLINK
cable in "Recommended Components", as they do not recommend its
use at all.

I didn't have the time or energy to experiment, so I went with
digital Coax. I am of course quite happy with it. Would a TOSLINK
cable in the same system sound different? Can't say - never tried it.

I don't actually understand why there should be a difference.
Bits is bits, right? This cable is simple transfering a bit stream
over a very short distance. Assuming all the bits arrive at the
same intervals as they went in, why should one cable "sound" different
from another? Do not know.

/jim

Colin wrote:
A stereo shop tried to sell me a better quality fiber optic cable, I don't
remember brand names or anything, they claimed better sound quality. The
regular cords were $20 to $30.00 and the good one was $70.00 Canadian
dollars. Do the people of this group fell it makes a difference what
TOSLINK cord you use. I thought all it had to do was pass on a digital
signal. What about digital coax.?

thanks,

Colin

On Sun, 24 Aug 2003 19:33:21 GMT, Jim Mauro
wrote:

Truth be told, I don't get it. A few years back, I bought an
external DAC, and needed a cable to run from the digital out of
my CD player to the DAC. Both TOSLINK and Coax where options.

I did a bit of research, and discovered that the golden ears of
audio (Stereophile, TAS) find digital Coax superior to TOSLINK,
without exception.

But, of course, there are always exceptions. I do recall a reviewer
finding that a particular DAC (Perpetual Technology?) sounded better
with TOSlink than coax.

Kal

In article bWd2b.188416$Oz4.51322@rwcrnsc54,
Kalman Rubinson wrote:

But, of course, there are always exceptions. I do recall a reviewer
finding that a particular DAC (Perpetual Technology?) sounded better
with TOSlink than coax.

Those must be some talented designers to make a D/A that can "resolve"
differences between digital interconnects. Does it somehow detect which
one is more expensive?

DC

On Mon, 25 Aug 2003 02:58:26 GMT, Dave Collins
wrote:

In article bWd2b.188416$Oz4.51322@rwcrnsc54,
Kalman Rubinson wrote:

But, of course, there are always exceptions. I do recall a reviewer
finding that a particular DAC (Perpetual Technology?) sounded better
with TOSlink than coax.

Those must be some talented designers to make a D/A that can "resolve"
differences between digital interconnects. Does it somehow detect which
one is more expensive?

Of course, the latter is easy. ;-) OTOH, it is also easy to
distinguish poor TOSlink (those with narrow bandwidth
transmitters/receivers) from coax. With the improvement in those
devices, differences between coax and TOSlink have mostly evaporated.

Kal

"Kalman Rubinson" wrote in message
news:bWd2b.188416$Oz4.51322@rwcrnsc54...
On Sun, 24 Aug 2003 19:33:21 GMT, Jim Mauro
wrote:

Truth be told, I don't get it. A few years back, I bought an
external DAC, and needed a cable to run from the digital out of
my CD player to the DAC. Both TOSLINK and Coax where options.

I did a bit of research, and discovered that the golden ears of
audio (Stereophile, TAS) find digital Coax superior to TOSLINK,
without exception.

But, of course, there are always exceptions. I do recall a reviewer
finding that a particular DAC (Perpetual Technology?) sounded better
with TOSlink than coax.


I found that once run through a DTI Pro de-jitterer, both sounded the same
into my Proceed PDP (which was very susceptible to jitter). And both
sounded better than they had without the DTI.

Is there a major difference between the output quality of RCA jacks compared
to Coax?
Yoan

"Jim Mauro" wrote in message
news:5q82b.184325$cF.62084@rwcrnsc53...
Truth be told, I don't get it. A few years back, I bought an
external DAC, and needed a cable to run from the digital out of
my CD player to the DAC. Both TOSLINK and Coax where options.

I did a bit of research, and discovered that the golden ears of
audio (Stereophile, TAS) find digital Coax superior to TOSLINK,
without exception. In fact, Stereophile does not include TOSLINK
cable in "Recommended Components", as they do not recommend its
use at all.

I didn't have the time or energy to experiment, so I went with
digital Coax. I am of course quite happy with it. Would a TOSLINK
cable in the same system sound different? Can't say - never tried it.

I don't actually understand why there should be a difference.
Bits is bits, right? This cable is simple transfering a bit stream
over a very short distance. Assuming all the bits arrive at the
same intervals as they went in, why should one cable "sound" different
from another? Do not know.

/jim

Colin wrote:
A stereo shop tried to sell me a better quality fiber optic cable, I
don't
remember brand names or anything, they claimed better sound quality.
The
regular cords were $20 to $30.00 and the good one was $70.00 Canadian
dollars. Do the people of this group fell it makes a difference what
TOSLINK cord you use. I thought all it had to do was pass on a digital
signal. What about digital coax.?

thanks,

Colin

On 26 Aug 2003 00:38:31 GMT, "Yoan Paquet"
wrote:

Is there a major difference between the output quality of RCA jacks compared
to Coax?

RCAs are one form of coax connector.

Kal

Kalman Rubinson wrote in message news:17C2b.196531$cF.65961@rwcrnsc53...
On 26 Aug 2003 00:38:31 GMT, "Yoan Paquet"
wrote:

Is there a major difference between the output quality of RCA jacks compared
to Coax?

RCAs are one form of coax connector.

Kal

I am not sure that this is the right place in this dicourse to post
this note but I'll do it anyhow

Below is one man's opinion. It is the result of forty years in the
digital data transmission business. This could be the result of one
years experience taken forty times or a progression of learning
experiences. I would be interested in contrary opinions, especially
if they have some rationale for them.

The ONLY important issue in optical vs. coax is whether the bit stream
input is the bit stream received. If the answer to this is "yes" then
there can be NO POSSIBLE difference in the sound that results from the
transmission! Bits are bits independently of how they are
transmitted.

In the world of analog transmission, many effects can alter sound
because the information (sound) is dependent on the INSTANTANEOUS
amplitude of the signal and that, in turn, is affected by the
instantaneous frequency of that signal. Digital signals are not
altered in their information content in the same way. It is much more
difficult to get a faithfully reproduced signal in the analog domain;
in fact, it is tantamount to impossible at any cost.

Fundamentally, coax is more susceptible transmission line effects than
is optical cable. Both media have loss as a function of length, but
coax is subject to signal degradation due to reflections and other
transmission line effects (the same bugaboos that plague analog
reproduction). Properly designed drivers and receivers minimize this
effect so that, in the ‘sloppy' world of digital data, they only
‘tighten up' the data clocking requirements on the system. The speed
and sensitivity of modern IC's make detection and clocking of the less
than 4 MHz data rate required for digital audio cheap and easy to
obtain for either coax or optical cables. Consider the fact that we
can obtain very cheap, very reliable data transmission at 100
Mbits/sec. or even 1 Gbit/sec. over CAT-5 cable, which is a more
difficult medium than is coax.

It is highly unlikely to have a driver, receiver, transmission line
trio that will pass some digital audio data streams and NOT others.

Further observations:

If an optical line works at all, then it will work with all data
streams. Reasonably well designed audio equipment (coax drivers and
receivers) are wildly unlikely to garble the stream because of
transmission line effects. Most drivers and receivers used in modern
gear are off-the-shelf IC's that do an admirable job. It is beyond
rationality for a manufacturer to design its own drivers, receivers,
and data clocking devices when cheap, effective devices are so widely
available. I certainly would not consider designing my own unless I
anticipated a production run of at least 1 million units. Even then,
I would probably specify an off-the-shelf device.

Net:

Optical is more likely to faithfully reproduce the input data stream
than is coax, but neither is at all likely to fail as implemented in
today's equipment.

It is SILLY to argue that one transmission line produces better sound
than another does. That argument is reserved for salespersons on
commission pay or who receive manufacturer's spiffs.

(steve behman) wrote in message . net...
"Colin" wrote in message news:gHC0b.204311$Ho3.27522@sccrnsc03...
A stereo shop tried to sell me a better quality fiber optic cable, I don't
remember brand names or anything, they claimed better sound quality. The
regular cords were $20 to $30.00 and the good one was $70.00 Canadian
dollars. Do the people of this group fell it makes a difference what
TOSLINK cord you use. I thought all it had to do was pass on a digital
signal. What about digital coax.?

thanks,

Colin

I think this is where the note below really belongs, sorry for having
misplaced it.

Below is one man's opinion. It is the result of forty years in the
digital data transmission business. This could be the result of one
years experience taken forty times or a progression of learning
experiences. I would be interested in contrary opinions, especially
if they have some rationale for them.

The ONLY important issue in optical vs. coax is whether the bit stream
input is the bit stream received. If the answer to this is "yes" then
there can be NO POSSIBLE difference in the sound that results from the
transmission! Bits are bits independently of how they are
transmitted.

In the world of analog transmission, many effects can alter sound
because the information (sound) is dependent on the INSTANTANEOUS
amplitude of the signal and that, in turn, is affected by the
instantaneous frequency of that signal. Digital signals are not
altered in their information content in the same way. It is much more
difficult to get a faithfully reproduced signal in the analog domain;
in fact, it is tantamount to impossible at any cost.

Fundamentally, coax is more susceptible transmission line effects than
is optical cable. Both media have loss as a function of length, but
coax is subject to signal degradation due to reflections and other
transmission line effects (the same bugaboos that plague analog
reproduction). Properly designed drivers and receivers minimize this
effect so that, in the Â?sloppy' world of digital data, they only
Â?tighten up' the data clocking requirements on the system. The speed
and sensitivity of modern IC's make detection and clocking of the less
than 4 MHz data rate required for digital audio cheap and easy to
obtain for either coax or optical cables. Consider the fact that we
can obtain very cheap, very reliable data transmission at 100
Mbits/sec. or even 1 Gbit/sec. over CAT-5 cable, which is a more
difficult medium than is coax.

It is highly unlikely to have a driver, receiver, transmission line
trio that will pass some digital audio data streams and NOT others.

Further observations:

If an optical line works at all, then it will work with all data
streams. Reasonably well designed audio equipment (coax drivers and
receivers) are wildly unlikely to garble the stream because of
transmission line effects. Most drivers and receivers used in modern
gear are off-the-shelf IC's that do an admirable job. It is beyond
rationality for a manufacturer to design its own drivers, receivers,
and data clocking devices when cheap, effective devices are so widely
available. I certainly would not consider designing my own unless I
anticipated a production run of at least 1 million units. Even then,
I would probably specify an off-the-shelf device.

Net:

Optical is more likely to faithfully reproduce the input data stream
than is coax, but neither is at all likely to fail as implemented in
today's equipment.

It is SILLY to argue that one transmission line produces better sound
than another does. That argument is reserved for salespersons on
commission pay or who receive manufacturer's spiffs.

This argument about Toslink vs. coax wasn't the reason for my original
post. What I was wondering was; is it possible for one toslink cable
to sound better that another? A $20.00 vs. a $70.00 fibre optic cable
assume a short ~4ft length. Or would this be considered selling snake
oil.

The next part was about digital coax and if a "special" cable is
needed for good sound quality.

thanks,

Colin

Colin,
Pardon me for being obtuse. The primary purpose of my note was to assure
you that the el cheapo Toslink will produce IDENTICALLY THE SAME BITSTRING
(and therefore sound) as the salesperson enrichening expensive one.
Especially in sight of the short distance. The length of the note was to
suggest the rationale for the conclusion.

The "Golden Ears" community is safe in the world of analog transducers and
transmission media because NO ONE knows what to measure or how to measure
it. The digital domain is much easier to characterize. Either you get
back EXACTLY what you put in or you do not. Moreover, this can be MEASURED
EXACTLY!

If you had a run somewhat longer than you contemplate, the opacity of
plastic as compared to glass could become a problem.

Another factor in favor of the el cheapo is that a few errors/Mbit would be
SWAMPED by the errors in the rest of the system's ADC and DAC components.
Note that both ADC's and DAC's are analog devices.

As we hams are so fond of saying "every new antenna gives a 3db gain over
the old one." That phenomonon's audioland equivalent is called
Psycho-acustics (emphasis on the PSYCHO!)

I hope that this discussion reduces your anxiety and leaves your wallet
fatter by $50.

Steve

"Colin" wrote in message
et...
(steve behman) wrote in message
. net...
"Colin" wrote in message
news:gHC0b.204311$Ho3.27522@sccrnsc03...
A stereo shop tried to sell me a better quality fiber optic cable, I
don't
remember brand names or anything, they claimed better sound quality.
The
regular cords were $20 to $30.00 and the good one was $70.00 Canadian
dollars. Do the people of this group fell it makes a difference
what
TOSLINK cord you use. I thought all it had to do was pass on a
digital
signal. What about digital coax.?

thanks,

Colin

I think this is where the note below really belongs, sorry for having
misplaced it.

Below is one man's opinion. It is the result of forty years in the
digital data transmission business. This could be the result of one
years experience taken forty times or a progression of learning
experiences. I would be interested in contrary opinions, especially
if they have some rationale for them.

The ONLY important issue in optical vs. coax is whether the bit stream
input is the bit stream received. If the answer to this is "yes" then
there can be NO POSSIBLE difference in the sound that results from the
transmission! Bits are bits independently of how they are
transmitted.

In the world of analog transmission, many effects can alter sound
because the information (sound) is dependent on the INSTANTANEOUS
amplitude of the signal and that, in turn, is affected by the
instantaneous frequency of that signal. Digital signals are not
altered in their information content in the same way. It is much more
difficult to get a faithfully reproduced signal in the analog domain;
in fact, it is tantamount to impossible at any cost.

Fundamentally, coax is more susceptible transmission line effects than
is optical cable. Both media have loss as a function of length, but
coax is subject to signal degradation due to reflections and other
transmission line effects (the same bugaboos that plague analog
reproduction). Properly designed drivers and receivers minimize this
effect so that, in the Ã,?sloppy' world of digital data, they only
Ã,?tighten up' the data clocking requirements on the system. The speed
and sensitivity of modern IC's make detection and clocking of the less
than 4 MHz data rate required for digital audio cheap and easy to
obtain for either coax or optical cables. Consider the fact that we
can obtain very cheap, very reliable data transmission at 100
Mbits/sec. or even 1 Gbit/sec. over CAT-5 cable, which is a more
difficult medium than is coax.

It is highly unlikely to have a driver, receiver, transmission line
trio that will pass some digital audio data streams and NOT others.

Further observations:

If an optical line works at all, then it will work with all data
streams. Reasonably well designed audio equipment (coax drivers and
receivers) are wildly unlikely to garble the stream because of
transmission line effects. Most drivers and receivers used in modern
gear are off-the-shelf IC's that do an admirable job. It is beyond
rationality for a manufacturer to design its own drivers, receivers,
and data clocking devices when cheap, effective devices are so widely
available. I certainly would not consider designing my own unless I
anticipated a production run of at least 1 million units. Even then,
I would probably specify an off-the-shelf device.

Net:

Optical is more likely to faithfully reproduce the input data stream
than is coax, but neither is at all likely to fail as implemented in
today's equipment.

It is SILLY to argue that one transmission line produces better sound
than another does. That argument is reserved for salespersons on
commission pay or who receive manufacturer's spiffs.

This argument about Toslink vs. coax wasn't the reason for my original
post. What I was wondering was; is it possible for one toslink cable
to sound better that another? A $20.00 vs. a $70.00 fibre optic cable
assume a short ~4ft length. Or would this be considered selling snake
oil.

The next part was about digital coax and if a "special" cable is
needed for good sound quality.

thanks,

Colin

Wylie Williams wrote:
"Colin" wrote
What I was wondering was; is it possible for one toslink cable
to sound better that another?

Colin,

My answer is: yes I think it is possible. I once had a store and sold a
wide price range of Toslinks. I let customers buy, try, and return till
they found the one they liked best. All preferred more expensive ones. I
have never compared, but I believe that my customers were competent to judge
their preferences, so I think it's possible. I never tried compared Toslinks
myself, but I believe that no design is so perfect that quality of materials
and construction can't make a difference in performance.

If you ask questions on RAHE that are intended to help you decide what
cables to buy you will generally get what you got: statement s that there is
no diffrence and technical explanations, followed by responses to the
responses starting a divergent discussion. If you want responses from
people who will tell their personal experiences and preferences try
www.audioasylum.com.

Actually, some of the people here at rahe are doing exactly that: that
*from their personal experiences and preferences* there are no
differences. Furthermore, you may even get an explanation why there is
no difference between cables.

Of course, if you want to hear people telling you that there are
differences, then Audio Asylum is where you belong.


Wylie Williams

I am not an expert in this area, but I would be at a loss
to find an intelligent argument to Steve's posting. A
bit-stream is a series of 1's and 0's represented electronically
as something that looks like a square wave - a serial stream
of 0 and non-zero voltage levels, where the incoming information
is either a "1" or a "0" - very, very different from analogue
signals. As long as the bits received match the bits sent, there
is no technical reason why one cable should result in a different
sound. For the lengths we're talking about here, say 1 to 3 meters,
the likelyhood of even a cheap cable dropping bits or injecting jitter
is very small.

Having said that, we all (well, certainly me! :^) suffer from
audio nervousa. Couple that with the "if it's more expensive, it
must be better" axiom, it's hard to resist spending the extra
dollars when we've invested so much time, energy and money in
other areas. The mind plays games as well, and we sit and listen
after swapping out the cheaper cable for the more expensive one, and
we're sure there's more detail, an improved sense of space, a
tighter bottom end, highs are less harsh, etc, etc...

Case in point (not to digress)...I'm about to invest about $200 in parts
to re-wire my Rega RB300 tonearm, and spend a night or 2 on the
painstaking task of installing the new wires and cartridge clamps.
Why? Well I am unhappy with the shoddy quality of the existing cartridge
clamps, and (suffering from audio nervousa), have read enough about
the dramatic improvements derived from re-wiring this arm.

Sure, it's easy to make a case that tonearm cartridge wires can
dramatically effect the quality of the music - a millivolt
level analogue signal on a device that has so much mechnical
movement (a turntable). I think we'd all agree that it's a task
worth undertaking.

When it's all done, will I hear a difference?

You bet I will!

:^)

/jim

Wylie Williams wrote:
"Colin" wrote

What I was wondering was; is it possible for one toslink cable
to sound better that another?


Colin,

My answer is: yes I think it is possible. I once had a store and sold a
wide price range of Toslinks. I let customers buy, try, and return till
they found the one they liked best. All preferred more expensive ones. I
have never compared, but I believe that my customers were competent to judge
their preferences, so I think it's possible. I never tried compared Toslinks
myself, but I believe that no design is so perfect that quality of materials
and construction can't make a difference in performance.

If you ask questions on RAHE that are intended to help you decide what
cables to buy you will generally get what you got: statement s that there is
no diffrence and technical explanations, followed by responses to the
responses starting a divergent discussion. If you want responses from
people who will tell their personal experiences and preferences try
www.audioasylum.com.

Wylie Williams

Steve Behman wrote:

The result of the above is that all observable colorations are a product
of the analog components and none of them are introduced while the signal
is in the digital domain...
Colin, until you see a rational refutation of my argument: save your money.

To suggest that digital is inherently perfect and analog inherently
flawed is - in itself - not rational in my view. The success of the
technology is always in the implementation, not the principle.

I have no digital technical knowledge, but I do have a memory of
reading the reigning experts of the 80s who said that CD and digital
technology would be perfect because when it is just 1s and 0s it makes a
perfect chain possible from recording to the home system. We are a long way
from then and still waiting for perfection, although various experts have
continued to report their progress in improving perfection. (Like Tide soap,
audio perfection comes in a new and improved version every year)
As I don't have the knowledge to know when to be skeptical when told
that "bits is bits- they're always OK", I am always skeptical.
Wylie Williams

"Jim Mauro" wrote in message
news:i7B4b.239448$cF.77237@rwcrnsc53...
I am not an expert in this area, but I would be at a loss
to find an intelligent argument to Steve's posting. A
bit-stream is a series of 1's and 0's represented electronically
as something that looks like a square wave - a serial stream
of 0 and non-zero voltage levels, where the incoming information
is either a "1" or a "0" - very, very different from analogue
signals. As long as the bits received match the bits sent, there
is no technical reason why one cable should result in a different
sound. For the lengths we're talking about here, say 1 to 3 meters,
the likelyhood of even a cheap cable dropping bits or injecting jitter
is very small.

Having said that, we all (well, certainly me! :^) suffer from
audio nervousa. Couple that with the "if it's more expensive, it
must be better" axiom, it's hard to resist spending the extra
dollars when we've invested so much time, energy and money in
other areas. The mind plays games as well, and we sit and listen
after swapping out the cheaper cable for the more expensive one, and
we're sure there's more detail, an improved sense of space, a
tighter bottom end, highs are less harsh, etc, etc...

Case in point (not to digress)...I'm about to invest about $200 in parts
to re-wire my Rega RB300 tonearm, and spend a night or 2 on the
painstaking task of installing the new wires and cartridge clamps.
Why? Well I am unhappy with the shoddy quality of the existing cartridge
clamps, and (suffering from audio nervousa), have read enough about
the dramatic improvements derived from re-wiring this arm.

Sure, it's easy to make a case that tonearm cartridge wires can
dramatically effect the quality of the music - a millivolt
level analogue signal on a device that has so much mechnical
movement (a turntable). I think we'd all agree that it's a task
worth undertaking.

When it's all done, will I hear a difference?

You bet I will!

:^)

/jim

Wylie Williams wrote:
"Colin" wrote

What I was wondering was; is it possible for one toslink cable
to sound better that another?


Colin,

My answer is: yes I think it is possible. I once had a store and
sold a
wide price range of Toslinks. I let customers buy, try, and return till
they found the one they liked best. All preferred more expensive ones.
I
have never compared, but I believe that my customers were competent to
judge
their preferences, so I think it's possible. I never tried compared
Toslinks
myself, but I believe that no design is so perfect that quality of
materials
and construction can't make a difference in performance.

If you ask questions on RAHE that are intended to help you decide
what
cables to buy you will generally get what you got: statement s that
there is
no diffrence and technical explanations, followed by responses to the
responses starting a divergent discussion. If you want responses from
people who will tell their personal experiences and preferences try
www.audioasylum.com.

Wylie Williams

In article ,
Terry Zagar wrote:

Your response was relatively reasonable until ...

Steve Behman wrote:

The only possible difference in reproducing sound through expensive digital
cables and cheap ones is the cost. Again, I remind the reader that CAT-5
cable transmits 100Mbit/sec digital signals FLAWLESSLY using
driver/receivers costing less than $4 over distances of 100's of feet at a
cost of $0.04/foot plus 40 cents for connectors!


What does CAT-5 cable transmitting two-way TCP/IP at 100 Mbps over
100's of feet have to do with TOSlink?

I believe his point was that one does not need highly or even moderately
expensive cable to get excellent performance with well designed digital
transmission systems. CAT-5 bears his point out quite well.

BTW, what does TCP/IP have to do with Ethernet? TCP/IP is a higher
layer protocol that couldn't care less whether its packets are
transmitted over Ethernet or some other physical layer. You seem
confused about the delineations between different networking layers as
you consistently talk about TCP/IP when, for the purposes of this
discussion, you should be concerned only with the physical layer.

b) TOSlink-based interconnections are based on a one-way,
point-to-point S/PDIF protocol, and not a two-way, network TCP/IP
protocol. S/PDIF uses a single parity bit for error correction.
Ethernet/TCP/IP provides for multi-bit parity checking, checksums, and
cyclic redundancy checks and supports requests for retransmission of
data packets to minimize transmission errors. S/PDIF is nowhere near
as robust as TCP/IP.

So what? In practice, even though Ethernet was engineered with
unreliable transmission as an acceptable tradeoff, errors are very rare
indeed on 100Base-T Ethernet. You can manage to get a noisy link, but
typically this is due to using crap network cards or poorly made cables
or violating maximum segment length, etc. It costs very little to build
Ethernet links that seldom lose a single bit.

c) TOSlink cable will be called upon to transmit a maximum data rate
of 12.8 MHz, limited by the transmitter and receiver used; most
transmitter/receiver components you are likely to find in audio
equipment are spec'd at a lower 6 MHz data rate.

Low bandwidth requirements mean that the cable doesn't have to be very
good to work perfectly, once again reinforcing the original poster's
point...

I've not seen any
maximum transmission rate specs for TOSlink plastic fiber cables, but
the Belden site
(http://bwcecom.belden.com/college/techpprs/wcfsbetp.HTM) suggests it
is "limited to low bandwidth of a few megahertz".

Literally right after it says: "The effect is that the signal can only
go a few feet, maybe 20 or 30 feet." This suggests that to the author a
"few megahertz" could mean 20 or 30 MHz.

--
Tim

Mr. Leeds, I specifically made no such claim. I did claim that there are
readily available, inexpensive devices for digital transmission which make
it extremely easy for a designer to use them and, having done so, to acheive
nearly flawless transmission (and, of course, detection) of digital data
much more demanding than S/PDIF.

That claim could not be made as recently as 10 or so years ago.

I will go further to argue: ONLY an incompetent designer would fail to use
these off-the-shelf components. They are completely debugged and the
MILLIONS of them in daily use attest to their efficacy. The designers of
these devices would be dismayed over the "low level" use to which they are
put in such a low speed, low accuracy* applications such as S/PDIF. After
all, most things are relative and they have designed and manufactured to a
vastly more stringent requirement.

*Not even those people blessed with the most Golden of ears could detect one
errant sample in 10,000, let alone one or fewer in a million.

Steve

"C. Leeds" wrote in message
news:VSU4b.249693$Oz4.67134@rwcrnsc54...
Steve Behman wrote:

The result of the above is that all observable colorations are a
product
of the analog components and none of them are introduced while the
signal
is in the digital domain...
Colin, until you see a rational refutation of my argument: save your
money.

To suggest that digital is inherently perfect and analog inherently
flawed is - in itself - not rational in my view. The success of the
technology is always in the implementation, not the principle.

On Tue, 02 Sep 2003 05:04:50 GMT, "Wylie Williams"
wrote:

I have no digital technical knowledge, but I do have a memory of
reading the reigning experts of the 80s who said that CD and digital
technology would be perfect because when it is just 1s and 0s it makes a
perfect chain possible from recording to the home system. We are a long way
from then and still waiting for perfection, although various experts have
continued to report their progress in improving perfection.

You are perhaps misunderstanding what is being said. There are
certainly problems with both A/D and D/A conversion, and associated
bandwidths and resolution, but once the signal is in digital form
(i.e. when it really is ones and zeroes), it is *extremely* robust,
and may be heavily abused with *zero* damage.

'Perfection' will only occur when we have agreement that say 24/192 is
correctly implemented (i.e. better than 120dB SNR and better than
50kHz bandwidth), and that this is sufficiently far outside our
ability to detect differences that the *analogue* signal cannot be
improved in any meaningful manner.

The raw truth remains that 16/44 is at the moment well outside what
most recording studios are capable of laying down.......
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Wylie,

I have seen no claim for the "perfection" of digital recordings; in fact, if
you read my note in this thread dated Aug. 31 10:50 PM I specifically note
that digital recordings are ABSOLUTELY IMPERFECT reproductions of the
original analog information (sound).

The transformation into the digital domain CHANGES the signal as does EVERY
recording of the sound waves. Moreover, it adds to the errors introduced by
the microphones, ADC's and analog recorders used to capture the sounds.

I do claim that ONCE IN THE DIGITAL DOMAIN, recording and transmission of
the imperfect representation of the sound can be accomplished cheaply and
easily WITHOUT further degradation of the original sound. That is, until
you try to play it back. At that point, it is IMPOSSIBLE to avoid further
degradation, well before it gets to your transducers (i.e. speakers,
headphones, ears).

In my experience, if you ignore the noise intrinsic to the pressing and
pickup, of well-made analog recordings ('black vinyl') are more satisfying
musically than are the DDD recordings. Unfortunately, the 'well-made'
qualifier eliminates 95+ percent of these recordings.

One more comment: No matter how high the "FI" a poor performance yields a
poor recording.

Steve

"Wylie Williams" wrote in message
news:SxV4b.329119$o%2.152004@sccrnsc02...
I have no digital technical knowledge, but I do have a memory of
reading the reigning experts of the 80s who said that CD and digital
technology would be perfect because when it is just 1s and 0s it makes a
perfect chain possible from recording to the home system. We are a long
way
from then and still waiting for perfection, although various experts have
continued to report their progress in improving perfection. (Like Tide
soap,
audio perfection comes in a new and improved version every year)
As I don't have the knowledge to know when to be skeptical when
told
that "bits is bits- they're always OK", I am always skeptical.
Wylie Williams

"Jim Mauro" wrote in message
news:i7B4b.239448$cF.77237@rwcrnsc53...
I am not an expert in this area, but I would be at a loss
to find an intelligent argument to Steve's posting. A
bit-stream is a series of 1's and 0's represented electronically
as something that looks like a square wave - a serial stream
of 0 and non-zero voltage levels, where the incoming information
is either a "1" or a "0" - very, very different from analogue
signals. As long as the bits received match the bits sent, there
is no technical reason why one cable should result in a different
sound. For the lengths we're talking about here, say 1 to 3 meters,
the likelyhood of even a cheap cable dropping bits or injecting jitter
is very small.

Having said that, we all (well, certainly me! :^) suffer from
audio nervousa. Couple that with the "if it's more expensive, it
must be better" axiom, it's hard to resist spending the extra
dollars when we've invested so much time, energy and money in
other areas. The mind plays games as well, and we sit and listen
after swapping out the cheaper cable for the more expensive one, and
we're sure there's more detail, an improved sense of space, a
tighter bottom end, highs are less harsh, etc, etc...

Case in point (not to digress)...I'm about to invest about $200 in parts
to re-wire my Rega RB300 tonearm, and spend a night or 2 on the
painstaking task of installing the new wires and cartridge clamps.
Why? Well I am unhappy with the shoddy quality of the existing cartridge
clamps, and (suffering from audio nervousa), have read enough about
the dramatic improvements derived from re-wiring this arm.

Sure, it's easy to make a case that tonearm cartridge wires can
dramatically effect the quality of the music - a millivolt
level analogue signal on a device that has so much mechnical
movement (a turntable). I think we'd all agree that it's a task
worth undertaking.

When it's all done, will I hear a difference?

You bet I will!

:^)

/jim

Wylie Williams wrote:
"Colin" wrote

What I was wondering was; is it possible for one toslink cable
to sound better that another?


Colin,

My answer is: yes I think it is possible. I once had a store and
sold a
wide price range of Toslinks. I let customers buy, try, and return
till
they found the one they liked best. All preferred more expensive
ones.
I
have never compared, but I believe that my customers were competent to
judge
their preferences, so I think it's possible. I never tried compared
Toslinks
myself, but I believe that no design is so perfect that quality of
materials
and construction can't make a difference in performance.

If you ask questions on RAHE that are intended to help you
decide
what
cables to buy you will generally get what you got: statement s that
there is
no diffrence and technical explanations, followed by responses to the
responses starting a divergent discussion. If you want responses from
people who will tell their personal experiences and preferences try
www.audioasylum.com.

Wylie Williams

In article , "Yoan Paquet"
writes:

Is there a major difference between the output quality of RCA jacks compared
to Coax?

I suppose the question is, is there a difference between RCA connectors and
other coaxial connectors (F, BNC, N, SMA etc. etc.). The answer is: Of course
there's a difference. For one thing, RCAs have no standard impedance. F = 75
ohms, BNC = 50 or 75 ohms, N = 50 and so on. The next question is: does it
really matter?

The correct impedance for digital audio cables and connectors is 75
ohms.(There's a whole other posting if you want to know WHY 75 ohms was
chosen.) In high frequency 'transmission line' systems, of which digital audio
is one, the critical distance for impedance is a quarter of a wavelength at the
frequency you are operating at. If your transmission line (i.e, cable and
connector) are the wrong impedance, they will reflect a portion of the signal
(depending on how far off the chosen impedance they are).

What is the frequency of digital audio? It depends on the sampling rate. What
is the sampling rate? 44.1 kHz. (If you are running 48 kHz, 96 kHz or
anything else, you can easily modify these calculations, but I will stick with
44.1 kHz for this example).

AES standards say the bandwidth of 44.1 kHz can be calculated by multiplying it
by 128. 44.1 x 128 = 5.6448 MHz. The wavelength of that is 300/5.6448 (that
answer comes out in meters, multiply them by 3.28 to get to feet) = 174 ft.
One quarter of that is 44 ft. That simply means that the cable, connector, or
anything else that the digital signal passes through would have to be at least
44 ft. before it would have an effect on "return loss" (reflected signals) .
(Some people say 1/10th of a wavelength or 17.4 ft..)

Either way, the length of one connector, regardless of the type or style, will
have no effect on the impedance, and therefore no effect digital signal. In
fact, the cable itself will have no effect in home home installs, because the
cable is very short.

However, the capacitance of the cable will have an effect since we're talking
about data, so low capacitance is better than high. Connectors might have a
ruggedness factor, a retention factors (RCA's call become intermittent or fall
out) and therefore a resistance factor. But that's about it.

Alternate opinions?

Steve Lampen
Belden Electronics Division
somewhere over the Pacific about to land in Japan

In article ,
(Colin) writes:

Optical is more likely to faithfully reproduce the input data stream
than is coax, but neither is at all likely to fail as implemented in
today's equipment.

I think, if you took a Toslink of a given length and a coax of identical
length, and looked at an eye pattern of the datastream you would indeed see a
difference. And, as you extend the length, these differences would become more
pronounced.

900 micron plastic fiber is huge by fiber standards. Common multimode fiber is
50 or 62.5 microns, single mode 8 microns. And the light source is visible
light in toslink, not the short wavlengths of glass fiber. After only a few
feet, optical signals in toslink are bouncing all around.

Anybody have a lab to test these? I would be glad to send a piece of coax (we
don't make toslink fiber or I would send that too).

Steve Lampen
Belden Electronics Division

Hello Timothy,

"Timothy A. Seufert" wrote:

I believe his point was that one does not need highly or even moderately
expensive cable to get excellent performance with well designed digital
transmission systems. CAT-5 bears his point out quite well.


I concur that that was the point Steve was trying to convey. But in a
digital transmission system operating at 100Mbps with cable runs of
100's of feet, I don't believe that the excellent performance observed
can be ascribed exclusively to the cable (although the cable does need
to be spec'd to handle this data rate-distance). Receivers,
transmitters, and error correction/control features associated with
transmission protocols (link, network and transport layers) also play
a critical role. My point is that a TOSlink-based transmission system
is nowhere near on the same level as what one might find in a
CAT-5/100Base-T installation.

BTW, what does TCP/IP have to do with Ethernet? TCP/IP is a higher
layer protocol that couldn't care less whether its packets are
transmitted over Ethernet or some other physical layer. You seem
confused about the delineations between different networking layers as
you consistently talk about TCP/IP when, for the purposes of this
discussion, you should be concerned only with the physical layer.


I agree that I made some fundamental (but reasonable) assumptions
here, but again my point was, and is, that focusing exclusively on the
physical layer is missing the larger picture of what's really going
on. But even on the physical level, I don't think anyone wants to
convey the suggestion that, by analogy, you'll have no transmission
errors with a 100 foot TOSlink cable. I don't believe Steve intended
to suggest this, but it is possible that someone could interpret his
statement that way, hence my original post.

b) TOSlink-based interconnections are based on a one-way,
point-to-point S/PDIF protocol, and not a two-way, network TCP/IP
protocol. S/PDIF uses a single parity bit for error correction.
Ethernet/TCP/IP provides for multi-bit parity checking, checksums, and
cyclic redundancy checks and supports requests for retransmission of
data packets to minimize transmission errors. S/PDIF is nowhere near
as robust as TCP/IP.

So what? In practice, even though Ethernet was engineered with
unreliable transmission as an acceptable tradeoff, errors are very rare
indeed on 100Base-T Ethernet. You can manage to get a noisy link, but
typically this is due to using crap network cards or poorly made cables
or violating maximum segment length, etc. It costs very little to build
Ethernet links that seldom lose a single bit.


Here you are supporting my argument. To get it to work as intended,
you need to implement it correctly. I'm not convinced that the
typical consumer will always follow best practices when mixing and
matching equipment and interconnects. This is why I questioned
Steve's argument that inferred that the characteristics of a
CAT-5/100Mbps implementation apply equally to a TOSlink
implementation. I don't consider that the best argument to make his
point because of the differences I cited.

c) TOSlink cable will be called upon to transmit a maximum data rate
of 12.8 MHz, limited by the transmitter and receiver used; most
transmitter/receiver components you are likely to find in audio
equipment are spec'd at a lower 6 MHz data rate.

Low bandwidth requirements mean that the cable doesn't have to be very
good to work perfectly, once again reinforcing the original poster's
point...


Actually, he didn't make this point. I was trying to make it for him.


I've not seen any
maximum transmission rate specs for TOSlink plastic fiber cables, but
the Belden site
(http://bwcecom.belden.com/college/techpprs/wcfsbetp.HTM) suggests it
is "limited to low bandwidth of a few megahertz".

Literally right after it says: "The effect is that the signal can only
go a few feet, maybe 20 or 30 feet." This suggests that to the author a
"few megahertz" could mean 20 or 30 MHz.


It is not at all clear, but in the worst case, if the bandwidth is
only say 3MHz over 20 to 30 foot distance, then to get a minimum 6MHz
bandwidth, one should limit TOSlink cable length to 10 to 15 feet.
This is in line with the AES recommendations. For 96kHz or 192kHz
signals, and/or more than 2 channels, then we're likely talking a
12MHz transmitter system in which case TOSlink cable length should be
limited to 5 to 7.5 feet. So again, if you keep cable lengths short,
things should be fine ... but I'd still really like to see a date
rate-distance spec for a TOSlink cable.

BTW, I'm not anti-TOSlink in any way, shape or form.

Best regards,

Terry

Hello Colin,

Terry Zagar wrote in message ...

d) AES recommends limiting TOSlink cables to a maximum length of
around 15 feet (5 meters). A particular TOSlink transmitter in an
audio component may not be able to drive that length of plastic cable.
For example, some TOSlink capable transmitters will guarantee only
0.2 meters maximum transmission distance. If you need to go to
distances longer than 5 meters, a repeater is required. A good CAT-5
cable, on the other hand is good for up to around 320 feet (100
meters). Interestingly, a glass (not plastic) fiber optic cable using
100baseFX is good for up to around 6,400 feet (2,000 meters).


Colin wrote:

Well this sounds like a limitation. 0.2 meters design length. If
this is a common limitation then fibre optic cable quality could make
a difference. Going back to college theory, there would be
reflections at both ends of the cable too(which if large enough could
interfere with the original signal) and the type of plastic/glass and
finish at the end of the fibre would affect the amount of internal
reflections. For the length limitation, the opacity would have an
effect too.

Maybe this all could make a difference to signal transmission?

You certainly seem to know your digital communications theory.

What do you think?


Rereading my earlier post, I noticed that I should have said that "0.2
meters" was the "minimum guaranteed transmisson distance", and not the
"maximum". So it's not quite as bad as it might seem. My apologies
for any confusion this may have caused.

Despite this, I would still be more concerned about TOSlink
transmitter performance than I would the performance of the TOSlink
cable itself. Consider the specifications for the Toshiba TOTX176
TOSlink transmitter:

http://www.sc-elec.demon.co.uk/totx176.pdf

As I read this spec, this particular part can "potentially" drive an
optical signal to a maximum transmission distance of 5 to 10 meters
(15 to 30 feet) depending on its implementation. But note that the
minimum guaranteed spec for these parts is 0.2 meters (about 9
inches!). Assuming a given audio component uses this particular part,
how does one know if:

1) It has a minimum or maximum performance TOSlink transmitter inside?

2) The manufacturer of the component actually tested the performance
of individual TOSlink transmitters as opposed to just plugging in
whatever the distributor sent them?

3) In the case that the manufacturer actually tests each TOSlink
transmitter part, what is their part acceptance criteria (1 meter, 2
meters, ...)?

I don't believe that the typical consumer will have the answer to any
of these questions available to them. So the safest course of action
is to err on the side of using as short a length of TOSlink cable as
an interconnect as possible.

But if you happen to have a well performing TOSlink transmitter inside
the component, I don't see the TOSlink cable as an issue within the
AES length recommendation (5 meters or less). And I wouldn't worry
about reflections/opacity adversely impacting transmission performance
if one follows this AES recommendation.

Cheers,

Terry

"ShLampen" wrote in message
...
In article ,
(Colin) writes:


I think, if you took a Toslink of a given length and a coax of identical
length, and looked at an eye pattern of the datastream you would indeed
see a
difference. And, as you extend the length, these differences would become
more
pronounced.

900 micron plastic fiber is huge by fiber standards. Common multimode
fiber is
50 or 62.5 microns, single mode 8 microns. And the light source is
visible
light in toslink, not the short wavlengths of glass fiber. After only a
few
feet, optical signals in toslink are bouncing all around.

Wow ! someone who appears to know what he is talking about.
It appears that you can learn something on this forum. Thanks Steve!
so for all the experts on this forum that a bit is either there or not and
the olde perennial argument that one a bit of copper wire is the .... has
now migrated to a bit of plastic pipe is the same as another bit and it
don't make no difference, DBT, ABX, tcpip et all.
cat-5 makes good speaker wire ! wouldn't use it for digital :¬)
so we now seen to a viable explanation for what those with EARS have been
saying for a while.
so where is your aural illusion now, (sorry self delusion now) ?

I live in hope of understanding what I hear.
Chris
there are 10 types of idiot.

On Sat, 06 Sep 2003 09:23:09 GMT, "chris"
wrote:

"ShLampen" wrote in message
...
In article ,
(Colin) writes:

I think, if you took a Toslink of a given length and a coax of identical
length, and looked at an eye pattern of the datastream you would indeed see a
difference. And, as you extend the length, these differences would become more
pronounced.

900 micron plastic fiber is huge by fiber standards. Common multimode fiber is
50 or 62.5 microns, single mode 8 microns. And the light source is visible
light in toslink, not the short wavlengths of glass fiber. After only a few
feet, optical signals in toslink are bouncing all around.

Wow ! someone who appears to know what he is talking about.
It appears that you can learn something on this forum. Thanks Steve!
so for all the experts on this forum that a bit is either there or not and
the olde perennial argument that one a bit of copper wire is the .... has
now migrated to a bit of plastic pipe is the same as another bit and it
don't make no difference, DBT, ABX, tcpip et all.
cat-5 makes good speaker wire ! wouldn't use it for digital :¬)
so we now seen to a viable explanation for what those with EARS have been
saying for a while.
so where is your aural illusion now, (sorry self delusion now) ?

Um, you might care to note that nothing in what Steve correctly stated
suggests that over a typical 1 metre cable, there will be *any*
difference in whatever linkage is used.

Oh, BTW, Steve is wrong in one respect. The light source has nothing
to do with the fibre. Monomode fibre (not 'single' mode) is just as
useful with visible light as with any other, and in actual fact glass
fibres are more commonly used with infrared emitters, which are of
*lower* frequency than visible light. This is largely because
ultraviolet light is rapidly absorbed by glass. Quartz fibres are much
better for the higher UV frequencies, although such light sources are
seldom used in practice.

Now, exactly what do you claim that your *ears* have told you?

I live in hope of understanding what I hear.

You might perhaps start by understanding what you read.....
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article , (Stewart
Pinkerton) writes:

Um, you might care to note that nothing in what Steve correctly stated
suggests that over a typical 1 metre cable, there will be *any*
difference in whatever linkage is used.

I would agree that, at 1m, the difference between any medium would be slight
(if even measurable). I do agree that, if a bitstream arrives with no errors,
it certainly doesn't matter HOW it got there!

Oh, BTW, Steve is wrong in one respect. The light source has nothing
to do with the fibre. Monomode fibre (not 'single' mode) is just as
useful with visible light as with any other, and in actual fact glass
fibres are more commonly used with infrared emitters, which are of
*lower* frequency than visible light.

Not sure why you deny me "single mode" when this is all it is ever called here
in the US. Is this a Transatlantic thing? In the Belden fiber section of the
catalog it is all single mode and multimode. I have never seen "monomode"
although the stuff is the same, regardless of what you call it. And the
difference between "monomode" and multimode (and toslink beyond that) is
"numerical aperture", the size of the opening through which the light will
pass. Small aperture allows more coherent (aligned) waves. That is why "mono"
goes so much farther than "multi" and "multi" goes so much farther than
"toslink".

Single (mono) mode: 8 microns

Multimode: 50 microns / 62.5 microns

Toslink: 900 microns.

Sure, visible light will go through all of them, but the glass fibers have
wavelength (frequency) windows (850nm/1300nm for multimode, 1310nm/1550nm for
single/mono). I think you have me on the actual "wavelength". Yes, these
wavelengths (in nm = nanometers) are all infrared.

ultraviolet light is rapidly absorbed by glass. Quartz fibres are much
better for the higher UV frequencies, although such light sources are
seldom used in practice.

Unaware there even is UV fiber! Learn something every day!

In conclusion...

Is there a difference between glass fiber and plastic fiber? Sure.

Could it be mesaured? Sure.

Is it big enough to make a difference in a bitstream. Probably not at 1m, but
certainly at longer distances, 10m, 20m, I would bet money you could see the
difference in an eye pattern or BERT (bit error rate tester).

Fair enough?

Steve Lampen
Belden Electronics Division

In article , Terry Zagar
writes:

This is why I questioned
Steve's argument that inferred that the characteristics of a
CAT-5/100Mbps implementation apply equally to a TOSlink
implementation.

My only intent was to inform those who think "optical" is superior because it
is newer, and copper is worse because it is "old technology" are sadly
mistaken. Every technology, old or new, must stand on its specific performance.


Steve Lampen