Optical audio connections
 

Arny Krueger wrote:

While they often don't know what they are doing and this is yet another
example of it, some high end audio guys are using unshielded twisted pair
for line-level interconnects as well. The point being that their mistake is
believing that it helps. It isn't nearly the disaster that some people would
have you believe.

Like people using Cat 5 for audio ?

Graham

Optical audio connections
 

In article ,
Phil Allison wrote:
In fact shielding doesn't help much with low frequency interference.


** It sure does with any unbalanced audio line - good shielding is
crucial.

It is also crucial to balanced lines, in relation to capacitively
injected noise and strong RF transmissions.

Pet, ever heard of star quad? It is the best balanced cable for
interference rejection and is pretty universal for pro mic circuits. And
has a rudimentary lapped screen - really only to provide the path for
phantom power. If screening was essential it would have a rather better
one.


Balanced I/O is the real thing.


** Nonsense.

Fact is, balancing has NO effect on magnetic field interference to a
line - it is only the TWISTING of the signal carrying pair has any
benefit in this regard.

That's not totally so either.

OTOH - a co-axial line **inherently rejects** all such interference.

More ********. No co-ax is totally screened against high magnetic fields -
which are rarely a problem anyway in practical use.

How many times do folk have to be told this.

Are you born again or something? Or Russ Andrews in disguise?

--
*I'm not being rude. You're just insignificant

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

Optical audio connections
 

"tony sayer"


OTOH - a co-axial line **inherently rejects** all such interference.


Can you explain in your own words..well perhaps tone it down a bit;, how
thats so?..


** A loop ( or coil ) of wire will both radiate and receive an alternating
magnetic field.

Think of hearing aid loops, loop antennas etc.

A length of co-ax will do neither - cos it simply has zero net loop area.

Due to its symmetry.



...... Phil

Optical audio connections
 

In article ,
Arny Krueger wrote:
Agreed. If anybody doing practical audio know about interference with
signal lines, its the car audio guys. This is the context from which I
draw some of this wisdom about the slender benefits of shielding.

Lighting circuits fed from thyristor dimmers in a TV studio take some
beating...

--
*Half the people in the world are below average.

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

Optical audio connections
 

David Looser wrote:

Accurate impedence balance to earth at each end of the line is also important.

VERY important indeed.

If you get a chance, go to one of Bill Whitlock's presentations ( he does them
for the AES from time to time). There's little that man doesn't know about
interconnections. I went about a year ago in London. I thought I was fairly
expert but I learned some new tricks.

Graham

Optical audio connections
 

Phil Allison wrote:

Never head of "quad core" mic cable ?

Starquad relies on TWO seperately balanced lines in inverse rotation to reject
magnetic interference even better than single balanced.

The shield is all but superficial in this instance (at audio freqs at least).

Graham

Optical audio connections
 

The usual Steaming Great Charlatan :


Starquad relies on TWO seperately balanced lines in inverse rotation to
reject
magnetic interference even better than single balanced.


** It is just a four conductor, twisted cable - there is NO additional
"balancing".

The four conductors are connected as pairs at each end to make two actual
conductors.

It significantly closes up the loop area, compared to single pair twisted.


The shield is all but superficial in this instance (at audio freqs at
least).


** ********.

http://www.canare.com/files/Cat11_p35.pdf




...... Phil

Optical audio connections
 

"Dave Plowman (Nutcase)
Phil Allison

** It sure does with any unbalanced audio line - good shielding is
crucial.

It is also crucial to balanced lines, in relation to capacitively
injected noise and strong RF transmissions.

Pet, ever heard of star quad?


** Do read the whole thread - ****wit.


It is the best balanced cable for
interference rejection and is pretty universal for pro mic circuits.

** ********.


And has a rudimentary lapped screen

** ********.


** Nonsense.

Fact is, balancing has NO effect on magnetic field interference to a
line - it is only the TWISTING of the signal carrying pair has any
benefit in this regard.

That's not totally so either.


** Go read why " star quad " is better - ****WIT.

It is all to do with the additional twisting !!!



....... Phil

Optical audio connections
 

Petert wrote:

I understand that the optical connectors are known as TOS Link -
correct?

TOS Link is only really designed for short runs. The fibre has relatively
high attenuation and the bandwidth of the transmitters and receivers is
barely adequate for the job, although it may have improved a bit in recent
years. I just checked with my studio installer friend and he said 10m is
the max using the very best quality parts.


And are there dongles available to interface between these
fibre connectors and SC/PC or LC connectors?

God knows.

For good long digital optical links you need low loss (probably glass
rather than plastic) fibre. Dunno if you can get that with a TOS Link
termination. Some heroes actually fit better optical connectors (typically
screw thread) on their kit for exactly this reason.


Are there advantages to be gained in using optical vice coax?
Is Cat5 or Cat6 used in audio? I will be installing structured cabling
for computing - is it worth installing extra runs for audio etc?

Do you understand balanced audio signals ?

Graham

Optical audio connections
 

"Eeyore" wrote in
message
Arny Krueger wrote:

While they often don't know what they are doing and this
is yet another example of it, some high end audio guys
are using unshielded twisted pair for line-level
interconnects as well. The point being that their
mistake is believing that it helps. It isn't nearly the
disaster that some people would have you believe.

Like people using Cat 5 for audio ?

Exactly.

And like saying that balanced I/O doesn't help lots.