Digital Cables
 

There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:

http://www.russandrews.com/product.asp?pf_id=2565

"£797.00: KIMBER Select KS-2120 Digital Balanced

"KS-2120 not only uses the highest purity silver, it incorporates
KIMBER's latest discoveries in the nature of digital signals. The
result? Even more detail and even more music. You have to hear this
cable between your CD transport and DAC to appreciate the massive
improvements it can bring."

--
Dave Farrance

Digital Cables
 

Dave Farrance wrote:
There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:

http://www.russandrews.com/product.asp?pf_id=2565

"£797.00: KIMBER Select KS-2120 Digital Balanced

"KS-2120 not only uses the highest purity silver, it incorporates
KIMBER's latest discoveries in the nature of digital signals. The
result? Even more detail and even more music. You have to hear this
cable between your CD transport and DAC to appreciate the massive
improvements it can bring."


I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference. AES-EBU
and SP-DIF signals are incredibly rugged, and provided the cable is of
75 ohms impedance, what it's made of and how constructed will have *no*
effect on the signal transmitted.

Balanced AES-EBU signals are even more immune to jitter caused by
50-60Hz hum and are the preferred choice for long cable runs.

I just don't know how Russ Andrews has the gall to sell this stuff.......

S.

Digital Cables
 

Serge Auckland wrote:

Dave Farrance wrote:

There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:

http://www.russandrews.com/product.asp?pf_id=2565

"£797.00: KIMBER Select KS-2120 Digital Balanced
"KS-2120 not only uses the highest purity silver, it incorporates
KIMBER's latest discoveries in the nature of digital signals. The
result? Even more detail and even more music. You have to hear this
cable between your CD transport and DAC to appreciate the massive
improvements it can bring."


I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.

Haven't heard from Glenn Richards recently.

--
Eiron.

Digital Cables
 

In article , Dave Farrance
writes
There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:

http://www.russandrews.com/product.asp?pf_id=2565

"£797.00: KIMBER Select KS-2120 Digital Balanced

"KS-2120 not only uses the highest purity silver, it incorporates
KIMBER's latest discoveries in the nature of digital signals. The
result? Even more detail and even more music. You have to hear this
cable between your CD transport and DAC to appreciate the massive
improvements it can bring."


Can't help but think its time he had a run in with the trading standards
authority?..

But perhaps they must think anyone who believes all that bull**** must
need sectioning anyway!....
--
Tony Sayer

Digital Cables
 

On Wed, 22 Nov 2006 18:34:37 GMT, Dave Farrance
wrote:

There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:


"What Hi-Fi" December issue has a page reporting a testing session for
skeptics. See:
www.laurencepayne.co.uk/cables.html

They report the session fairly accurately, if selectively.

Throughout the magazine they continue to rave over magic cables. But,
to give due credit, several times they add "but see p.121 for another
opinion". I wonder if this qualification will persist in future
issues?

Digital Cables
 

"Serge Auckland"
wrote in message ...
:
: I don't think that anybody that knows how digital audio is
transmitted
: would believe that *any* digital cable will make a
difference. AES-EBU
: and SP-DIF signals are incredibly rugged, and provided the
cable is of
: 75 ohms impedance, what it's made of and how constructed
will have *no*
: effect on the signal transmitted.
:
: Balanced AES-EBU signals are even more immune to jitter
caused by
: 50-60Hz hum and are the preferred choice for long cable
runs.
:
:
: S.
:

Isn't AES/EBU digital cable 110Ohm?

Regards TT

Digital Cables
 

In article , TT TTencerNOmorespam@westnet.
com.au writes

"Serge Auckland"
wrote in message ...
:
: I don't think that anybody that knows how digital audio is
transmitted
: would believe that *any* digital cable will make a
difference. AES-EBU
: and SP-DIF signals are incredibly rugged, and provided the
cable is of
: 75 ohms impedance, what it's made of and how constructed
will have *no*
: effect on the signal transmitted.
:
: Balanced AES-EBU signals are even more immune to jitter
caused by
: 50-60Hz hum and are the preferred choice for long cable
runs.
:
:
: S.
:

Isn't AES/EBU digital cable 110Ohm?

Regards TT



Yes. As robust as it is it don't like longish lumps of twin mic cable of
the wrong sort...
--
Tony Sayer

Digital Cables
 

In article , Laurence Payne
lpayne1NOSPAM@dslDOTpipexDOTcom wrote:
On Wed, 22 Nov 2006 18:34:37 GMT, Dave Farrance
wrote:

There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:


"What Hi-Fi" December issue has a page reporting a testing session for
skeptics. See: www.laurencepayne.co.uk/cables.html

They report the session fairly accurately, if selectively.

Throughout the magazine they continue to rave over magic cables. But,
to give due credit, several times they add "but see p.121 for another
opinion". I wonder if this qualification will persist in future issues?


Interesting that it is presented as "another opinion". i.e. Not presented
on the basis that actual evidence either fails to support, or contradicts
much of what they print. Or that they have no idea how to run a comparison
that might give reliable results. :-)

If you want a stark example of what Russ Andrews says, have a look at his
new 'column' sigh in 'Hi Fi News' this month. Given that he sells these
things I must confess I find it puzzling that he is now has such a column
which appears as *editorial* matter, not advertising, in such a magazine.
My reaction is that there is a conflict of interest, here.

BTW Dave, if you want to see a wider range of the kinds of views and
reactions people have to 'cables', then try a search back on this
group and some of the others. IIRC It has been a few weeks since we had
a 'local' argument about this. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Digital Cables
 

TT wrote:
"Serge Auckland"
wrote in message ...
:
: I don't think that anybody that knows how digital audio is
transmitted
: would believe that *any* digital cable will make a
difference. AES-EBU
: and SP-DIF signals are incredibly rugged, and provided the
cable is of
: 75 ohms impedance, what it's made of and how constructed
will have *no*
: effect on the signal transmitted.
:
: Balanced AES-EBU signals are even more immune to jitter
caused by
: 50-60Hz hum and are the preferred choice for long cable
runs.
:
:
: S.
:

Isn't AES/EBU digital cable 110Ohm?

Regards TT


AES-EBU or AES-3 as the standard is known can be either 110 ohms
balanced or 75 ohms unbalanced. The signal format is identical, and is
also interchangeable with SP-DIF. The differences are in the settings of
one or more data bits which identify the signal, and in the nominal
signal level. SP-DIF is 0.5v and AES-EBU is 1V,if I remember correctly.
Connectors are normally XLR for balanced AES-EBU, BNC for unbalanced
AES-EBU and phono for SP-DIF

One benefit of using 75 ohm unbalanced AES-EBU is that in a mixed
audio-video facility, all cables are 75 ohms on BNCs, so the same cable
can be used for audio and video.

In an audio-only facility it is better to use all balanced 110 ohm cable
for analogue and digital so again, any balanced cable can be used for
either. The danger comes in older facilities which still have a lot of
balanced non-110 ohm cable, and that gets used for digital audio. As
rugged as AES-EBU is, it doesn't take kindly to long lengths of the
wrong impedance cable.

S.

Digital Cables
 

Jim Lesurf wrote:
In article , Laurence Payne
lpayne1NOSPAM@dslDOTpipexDOTcom wrote:
On Wed, 22 Nov 2006 18:34:37 GMT, Dave Farrance
wrote:

There was talk on another group about credulity and hugely expensive
cables. I was just wondering if *anybody* was prepared to say that they
believe the claims for a cable like this, for example:


"What Hi-Fi" December issue has a page reporting a testing session for
skeptics. See: www.laurencepayne.co.uk/cables.html

They report the session fairly accurately, if selectively.

Throughout the magazine they continue to rave over magic cables. But,
to give due credit, several times they add "but see p.121 for another
opinion". I wonder if this qualification will persist in future issues?


Interesting that it is presented as "another opinion". i.e. Not presented
on the basis that actual evidence either fails to support, or contradicts
much of what they print. Or that they have no idea how to run a comparison
that might give reliable results. :-)

If you want a stark example of what Russ Andrews says, have a look at his
new 'column' sigh in 'Hi Fi News' this month. Given that he sells these
things I must confess I find it puzzling that he is now has such a column
which appears as *editorial* matter, not advertising, in such a magazine.
My reaction is that there is a conflict of interest, here.

I have been a monthly reader of Hi-Fi News since it had a yellow border,
and its current incarnation may well see me not renewing my
subscription. Apart from the occasional sensible article (a recent one
by a certain Mr Lesurf included), they now run so-called articles by
Russ Andrews promoting fairy-dust, have dropped John Crabbe's column,
have long since dropped a regular Radio article, have the ridiculous
Hi-Fi Doctor dispensing plain wrong advice and their new tabloid style
with colour splashes everywhere and wacky picture positioning makes me
feel seasick. Even the outrageous Ken Kessler has gone. I seldom agreed
with Kessler's writings, but at least he *can* write, and was amusing.
The only saving grace is that they have Janine Elliot now writing for
them, but in a lightweight column. Janine would brighten my day on my
visits to BH, and definitely knows about audio.

Rant over.

S.

Digital Cables
 

On Thu, 23 Nov 2006 09:33:03 +0000 (GMT), Jim Lesurf
wrote:


Throughout the magazine they continue to rave over magic cables. But,
to give due credit, several times they add "but see p.121 for another
opinion". I wonder if this qualification will persist in future issues?


Interesting that it is presented as "another opinion". i.e. Not presented
on the basis that actual evidence either fails to support, or contradicts
much of what they print. Or that they have no idea how to run a comparison
that might give reliable results. :-)


The editor had rather nice tits.

Digital Cables
 

Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference. AES-EBU
and SP-DIF signals are incredibly rugged, and provided the cable is of
75 ohms impedance, what it's made of and how constructed will have *no*
effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Digital Cables
 

In article , Anton
Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another. Domestic audio
co-ax is not specified in terms of its impedance as that isn't normally
relevant. What *may* matter is the value for its capacitance per metre.
This is quoted in some catalogues - e.g. by Maplin. But tends not to be
mentioned in magazine 'reviews' sic of cables.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Digital Cables
 

Anton Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference. AES-EBU
and SP-DIF signals are incredibly rugged, and provided the cable is of
75 ohms impedance, what it's made of and how constructed will have
*no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

It really all depends on the construction of the cable. If it's coaxial
with a single stranded or solid central core, dielectric to an outer
screen, it will most likely be in the region of 40-100 ohms. If it's a
twisted pair with an outer screen then perhaps 80-130 ohms.
The exact value will depend on the dimensions, dielectric properties of
the insulations, method of construction etc. so it's not really possible
to define a "normal" cable, but in my experience, albeit of many years
ago, these were the typical figures I recall.

S.

Digital Cables
 

Serge Auckland wrote:

Anton Gijsen wrote:

Serge Auckland wrote:

I don't think that anybody that knows how digital audio is
transmitted would believe that *any* digital cable will make a
difference. AES-EBU and SP-DIF signals are incredibly rugged, and
provided the cable is of 75 ohms impedance, what it's made of and how
constructed will have *no* effect on the signal transmitted.


Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?


It really all depends on the construction of the cable. If it's coaxial
with a single stranded or solid central core, dielectric to an outer
screen, it will most likely be in the region of 40-100 ohms. If it's a
twisted pair with an outer screen then perhaps 80-130 ohms.
The exact value will depend on the dimensions, dielectric properties of
the insulations, method of construction etc. so it's not really possible
to define a "normal" cable, but in my experience, albeit of many years
ago, these were the typical figures I recall.

The characteristic impedance doesn't apply at audio frequencies,
so you can just consider the CLR values.

--
Eiron.

Digital Cables
 

In article , Serge Auckland
wrote:


I have been a monthly reader of Hi-Fi News since it had a yellow border,
and its current incarnation may well see me not renewing my
subscription. Apart from the occasional sensible article (a recent one
by a certain Mr Lesurf included), they now run so-called articles by
Russ Andrews promoting fairy-dust, have dropped John Crabbe's column,
have long since dropped a regular Radio article,

FWIW I also regret the dissapearance of John Crabbe as well as 'radio'.
Indeed, I feel that HFN would benefit from more regular info on both radio
and recording. I'd also love to see more (informative) articles on
classic/old equipment. In particular I'd love to see reprints of some of
the technical articles. e.,g.s including the Jim Sugden articles on his
class A amp, and the Radford series on his valve amps. In both cases these
gave considerable design details. Past articles by all kinds of
knowledgeable folk like Stan Kelly, etc, also spring to mind...


have the ridiculous Hi-Fi Doctor dispensing plain wrong advice and their
new tabloid style with colour splashes everywhere and wacky picture
positioning makes me feel seasick.

In this month's issue there is an edited-down version of an article on
'clipping on CD'. There was a last-min panic with this as the deputy editor
urgently needed some 'quotes/facts' to put into the three 'blobs' on the
final page. The layout was pre-fixed, so something for the blobs *had* be
to found. Must admit that this seemed to me like the cart driving the
horse, and simply gave the poor over-worked deputy editor more work to do.
However, suitable wordings were duly found.

[BTW since on the topic. The editorial comment at the end of the of the
article re the programs used for the article is incorrect. All the results
in the article stem from programs I wrote and used. But there *is* also now
a 'windows' equivalent which Keith Howard kindly wrote as I am useless at
programming for windows boxen. :-) So if you have a windows machine you
can download and use Keith's program to get analysis results for your own
CDs similar to those in the article. ]


Even the outrageous Ken Kessler has gone. I seldom agreed with Kessler's
writings, but at least he *can* write, and was amusing.

I confess that I do not miss KK. :-)

...but I'd much prefer John Crabbe to Russ Andrews!

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Digital Cables
 

In article ,
Anton Gijsen wrote:
I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

It doesn't matter since domestic audio connections aren't matched. They
will be typically something like a 50 ohm output and a 50 kohm input.
Unlike video which is usually 75 ohms in and out.

However, most co-ax cable used for phono circuits will be centred around
75 ohms.

--
*Oh, what a tangled website we weave when first we practice *

Dave Plowman London SW
To e-mail, change noise into sound.

Digital Cables
 

Eiron wrote:
Serge Auckland wrote:

Anton Gijsen wrote:

Serge Auckland wrote:

I don't think that anybody that knows how digital audio is
transmitted would believe that *any* digital cable will make a
difference. AES-EBU and SP-DIF signals are incredibly rugged, and
provided the cable is of 75 ohms impedance, what it's made of and
how constructed will have *no* effect on the signal transmitted.


Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?


It really all depends on the construction of the cable. If it's
coaxial with a single stranded or solid central core, dielectric to an
outer screen, it will most likely be in the region of 40-100 ohms. If
it's a twisted pair with an outer screen then perhaps 80-130 ohms.
The exact value will depend on the dimensions, dielectric properties
of the insulations, method of construction etc. so it's not really
possible to define a "normal" cable, but in my experience, albeit of
many years ago, these were the typical figures I recall.

The characteristic impedance doesn't apply at audio frequencies,
so you can just consider the CLR values.

A minor correction in the interest of precision: Characteristic
impedance *does* apply at all frequencies, it's just that it's
irrelevant for analogue audio frequency signals on the sort of lengths
used domestically. If you were to be setting up analogue music-lines as
the Post Office had up to a few years ago when distances could be many
hundreds of kilometres, it was certainly relevant.

S.

Digital Cables
 

Serge Auckland wrote:

Eiron wrote:

Serge Auckland wrote:

Anton Gijsen wrote:

Serge Auckland wrote:

I don't think that anybody that knows how digital audio is
transmitted would believe that *any* digital cable will make a
difference. AES-EBU and SP-DIF signals are incredibly rugged, and
provided the cable is of 75 ohms impedance, what it's made of and
how constructed will have *no* effect on the signal transmitted.



Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?



It really all depends on the construction of the cable. If it's
coaxial with a single stranded or solid central core, dielectric to
an outer screen, it will most likely be in the region of 40-100 ohms.
If it's a twisted pair with an outer screen then perhaps 80-130 ohms.
The exact value will depend on the dimensions, dielectric properties
of the insulations, method of construction etc. so it's not really
possible to define a "normal" cable, but in my experience, albeit of
many years ago, these were the typical figures I recall.


The characteristic impedance doesn't apply at audio frequencies,
so you can just consider the CLR values.

A minor correction in the interest of precision: Characteristic
impedance *does* apply at all frequencies, it's just that it's
irrelevant for analogue audio frequency signals on the sort of lengths
used domestically. If you were to be setting up analogue music-lines as
the Post Office had up to a few years ago when distances could be many
hundreds of kilometres, it was certainly relevant.

Another minor correction: The characteristic impedance of a cable
applies above its corner frequency. Below that the impedance increases
with decreasing frequency so driving and terminating resistors won't
stop reflections over a range of frequencies.

Can some kind soul please tell Anton what the impedance of a "normal"
analogue phono-phono cable is and what frequency range it applies to?

--
Eiron.

Digital Cables
 

Eiron wrote:
Serge Auckland wrote:

Eiron wrote:

Serge Auckland wrote:

Anton Gijsen wrote:

Serge Auckland wrote:

I don't think that anybody that knows how digital audio is
transmitted would believe that *any* digital cable will make a
difference. AES-EBU and SP-DIF signals are incredibly rugged, and
provided the cable is of 75 ohms impedance, what it's made of and
how constructed will have *no* effect on the signal transmitted.



Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?



It really all depends on the construction of the cable. If it's
coaxial with a single stranded or solid central core, dielectric to
an outer screen, it will most likely be in the region of 40-100
ohms. If it's a twisted pair with an outer screen then perhaps
80-130 ohms.
The exact value will depend on the dimensions, dielectric properties
of the insulations, method of construction etc. so it's not really
possible to define a "normal" cable, but in my experience, albeit of
many years ago, these were the typical figures I recall.


The characteristic impedance doesn't apply at audio frequencies,
so you can just consider the CLR values.

A minor correction in the interest of precision: Characteristic
impedance *does* apply at all frequencies, it's just that it's
irrelevant for analogue audio frequency signals on the sort of lengths
used domestically. If you were to be setting up analogue music-lines
as the Post Office had up to a few years ago when distances could be
many hundreds of kilometres, it was certainly relevant.

Another minor correction: The characteristic impedance of a cable
applies above its corner frequency. Below that the impedance increases
with decreasing frequency so driving and terminating resistors won't
stop reflections over a range of frequencies.

Right! I was wrong on this, I forgot about the lower cut-off frequency.

Can some kind soul please tell Anton what the impedance of a "normal"
analogue phono-phono cable is and what frequency range it applies to?

Impedances as above, but as to what frequency they apply above, it
depends on the capacitance and inductance characteristics of the cable.
The formula is Fc=2/2Pi x root(LC) according to my reference, where L is
the inductance/unit length and C is the capacitance /unit length.
Characteristic impedance is root (L/C) above the cut-off frequency Fc.

Trying a few typical L and C values for coax cables, I get Fc of several
MHz, so Eiron is right that not only it isn't relevant at audio
frequencies, but the characteristic impedance is way over the nominal 75
ohms (or whatever) until frequencies of several MHz are reached.


S.

Digital Cables
 

In article , Dave Plowman (News)
wrote:


However, most co-ax cable used for phono circuits will be centred around
75 ohms.

My recollection is that the values for 'audio' analog coaxs tend to be for
capacitances in the range from below 100pF/m to around 600 pF/m. This
implies a wide range of impedances - even if we ignore the effects of the
cable resistances, etc, which will change the values in a frequency
dependent manner at audio frequencies.

Fortunately, it doesn't matter much. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Digital Cables
 

In article , Serge Auckland
wrote:
Eiron wrote:


The characteristic impedance doesn't apply at audio frequencies, so
you can just consider the CLR values.

A minor correction in the interest of precision: Characteristic
impedance *does* apply at all frequencies,

As my own minor correction: I'd prefer to say that 'apply' here might be
better used to mean the decision of the person who wants to analyse or
assess the behaviour. On that basis, I'd say that it generally makes little
sense to try to apply characteristic impedance as your analysis model to
domestic analogue audio cables if only dealing with audible signals. There
are much simpler methods.

Slainte,

Jim



it's just that it's
irrelevant for analogue audio frequency signals on the sort of lengths
used domestically. If you were to be setting up analogue music-lines as
the Post Office had up to a few years ago when distances could be many
hundreds of kilometres, it was certainly relevant.

S.

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Digital Cables
 

In article , Serge Auckland
wrote:


Impedances as above, but as to what frequency they apply above, it
depends on the capacitance and inductance characteristics of the cable.
The formula is Fc=2/2Pi x root(LC) according to my reference, where L is
the inductance/unit length and C is the capacitance /unit length.
Characteristic impedance is root (L/C) above the cut-off frequency Fc.

I don't recall the formula, so the above may be correct. However its form
surprises me as I'd expect the value to depend upon the resistance (R')
and/or shunt conductance (G') per unit length as well as the capacitance
(C') and inductance (L') values...

My recollection is that, if we neglect shunt conductance and dielectric
losses, then the characteristic impedance turn over would be at the
frequency where jwL' is comparable with R'.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Digital Cables
 

On Fri, 24 Nov 2006 15:49:21 +0000 (GMT), Jim Lesurf
wrote:

In article , Serge Auckland
wrote:


Impedances as above, but as to what frequency they apply above, it
depends on the capacitance and inductance characteristics of the cable.
The formula is Fc=2/2Pi x root(LC) according to my reference, where L is
the inductance/unit length and C is the capacitance /unit length.
Characteristic impedance is root (L/C) above the cut-off frequency Fc.

I don't recall the formula, so the above may be correct. However its form
surprises me as I'd expect the value to depend upon the resistance (R')
and/or shunt conductance (G') per unit length as well as the capacitance
(C') and inductance (L') values...

My recollection is that, if we neglect shunt conductance and dielectric
losses, then the characteristic impedance turn over would be at the
frequency where jwL' is comparable with R'.

Slainte,

Jim

The formula is sqrt((R + jwL)/(G + jwC)), where G is the conductivity
of the dielectric, and R is the resistance of the wire - all for the
standard length that yields the L and C values.

I've worked and example with some typical values, and you can see that
the effect only comes into play at lowish frequencies. By the time you
get up towards the top of the band, where it might matter, the cable
has returned to its true impedance, and the lumped model is no longer
needed to describe it - the transmission line is just fine.

http://81.174.169.10/odds/cable.html

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital Cables
 

Jim Lesurf wrote:
In article , Anton
Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another.

Holy **** on a stick, guys! I didn't mean to start a friggin' argument.
What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75 Ohm
impedance digital coaxial cable. Maybe if I could get hold of some phono
connectors that B&Q satellite coax cable would be good. Your thoughts...?

Digital Cables
 

On Fri, 24 Nov 2006 16:29:56 +0000, Anton Gijsen
wrote:

Jim Lesurf wrote:
In article , Anton
Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another.

Holy **** on a stick, guys! I didn't mean to start a friggin' argument.
What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75 Ohm
impedance digital coaxial cable. Maybe if I could get hold of some phono
connectors that B&Q satellite coax cable would be good. Your thoughts...?

If that is the question, the answer is really simple - no. You will
know if the impedance of a digital connection is a problem, because
you will get errors in the data stream that cause ticks and burps. If
you don't have any of these, you have a clean signal and the impedance
of the cable is not causing problems.

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital Cables
 

Anton Gijsen wrote:
Jim Lesurf wrote:
In article , Anton
Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another.

Holy **** on a stick, guys! I didn't mean to start a friggin' argument.
What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75 Ohm
impedance digital coaxial cable. Maybe if I could get hold of some phono
connectors that B&Q satellite coax cable would be good. Your thoughts...?

That would be perfect. Just check that the cable is 75 ohm, not 50 ohms
and you're away.

By the way, There's a good chance that the "normal" phono-phono cable is
around 75 ohms. Also, on short lengths, even a bit of wet string will
work- literally. I've done it, and a few years ago, Canford Audio
demonstrated this at a couple of Trade Shows.

As to what we're like, we probably have too much time on our hands........

S.

Digital Cables
 

Serge Auckland wrote:
Anton Gijsen wrote:
Jim Lesurf wrote:
In article , Anton
Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another.

Holy **** on a stick, guys! I didn't mean to start a friggin'
argument. What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75
Ohm impedance digital coaxial cable. Maybe if I could get hold of some
phono connectors that B&Q satellite coax cable would be good. Your
thoughts...?

That would be perfect. Just check that the cable is 75 ohm, not 50 ohms
and you're away.

It is. I'll go and raid my local electronics shop tomorrow.

By the way, There's a good chance that the "normal" phono-phono cable is
around 75 ohms. Also, on short lengths, even a bit of wet string will
work- literally. I've done it, and a few years ago, Canford Audio
demonstrated this at a couple of Trade Shows.

Incredible! Not sure why anyone would want to do it, but I like the idea
of it.

As to what we're like, we probably have too much time on our hands........

Well, I wish I knew as much about electronics as you lot.

Digital Cables
 

Don Pearce wrote:
On Fri, 24 Nov 2006 16:29:56 +0000, Anton Gijsen
wrote:

Jim Lesurf wrote:
In article , Anton
Gijsen wrote:
Serge Auckland wrote:
I don't think that anybody that knows how digital audio is transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.
Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?
Not really, since it will vary from one example to another.
Holy **** on a stick, guys! I didn't mean to start a friggin' argument.
What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75 Ohm
impedance digital coaxial cable. Maybe if I could get hold of some phono
connectors that B&Q satellite coax cable would be good. Your thoughts...?

If that is the question, the answer is really simple - no. You will
know if the impedance of a digital connection is a problem, because
you will get errors in the data stream that cause ticks and burps. If
you don't have any of these, you have a clean signal and the impedance
of the cable is not causing problems.

Nope, no ticks/burps/clicking/artifacts whatsoever. It just doesn't
sound as good as using the analogue output of my CD player, but half of
the selling point of my CD player is the DAC, so that might explain it.

Thankyou very much for your help.

Digital Cables
 

In article ,
Anton Gijsen wrote:
Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another.

Holy **** on a stick, guys! I didn't mean to start a friggin' argument.
What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75 Ohm
impedance digital coaxial cable.

Does it work? Or produce crashing and banging noises? Because if a digital
connection like this sounds ok it is ok - there are no shades of grey.

Maybe if I could get hold of some phono
connectors that B&Q satellite coax cable would be good. Your thoughts...?

Pointless.

--
*Money isn‘t everything, but it sure keeps the kids in touch

Dave Plowman London SW
To e-mail, change noise into sound.

Digital Cables
 

Anton Gijsen wrote:
Serge Auckland wrote:
Anton Gijsen wrote:
Jim Lesurf wrote:
In article , Anton
Gijsen wrote:
Serge Auckland wrote:

I don't think that anybody that knows how digital audio is
transmitted
would believe that *any* digital cable will make a difference.
AES-EBU and SP-DIF signals are incredibly rugged, and provided the
cable is of 75 ohms impedance, what it's made of and how constructed
will have *no* effect on the signal transmitted.

Can some kind soul please tell me what the impedance of a "normal"
analogue phono-phono cable is?

Not really, since it will vary from one example to another.

Holy **** on a stick, guys! I didn't mean to start a friggin'
argument. What are you lot like?

The reason I asked is that I'm currently using a "normal" analogue
phono-phono cable as a digital cable between my CD player and AV amp,
and was wondering whether or not it was worth getting a "proper" 75
Ohm impedance digital coaxial cable. Maybe if I could get hold of
some phono connectors that B&Q satellite coax cable would be good.
Your thoughts...?

That would be perfect. Just check that the cable is 75 ohm, not 50
ohms and you're away.

It is. I'll go and raid my local electronics shop tomorrow.

By the way, There's a good chance that the "normal" phono-phono cable
is around 75 ohms. Also, on short lengths, even a bit of wet string
will work- literally. I've done it, and a few years ago, Canford Audio
demonstrated this at a couple of Trade Shows.

Incredible! Not sure why anyone would want to do it, but I like the idea
of it.

Because you can! It looks really cool to have fish swimming about around
your digital interconnect........

S.

Digital Cables
 

Janine would brighten my day on my visits to BH, and definitely knows
about audio.

Janine would brighten my day any time I saw her! Drool, drool.

Russ Andrews as editorial really is putting Dracula in charge of the
bloodbank. How silly can it get? There were days when I read HFN for
articles by the likes of Jean Hiraga. The serious mags are all gone the
way of Audio Amateur.

Andy