[toecheese]

I'm looking to buy cabling to run line-level stereo audio through the
walls of my home (tape mon output of one receiver/amp, thru walls and
into another amp). It's for an outdoor stereo so I don't need the
end-all-be-all best sound, just decent, humless audio. The most common
cabling choice seems to be Belden 9451D. Another Belden cable, 8723,
looks identical--I can't see what the difference is. Does anyone have an
opinion on which is better? I'd prefer the 8723 since I can find it sold
by the foot, the 9451D is only available in bulk.

Belden 8723: http://www.weisd.com/store2/BEL8723%20060U1000B.html

Belden 9451D: http://www.sjmediasystem.com/bl-9451d-1000.html

[Richard Crowley]

"toecheese" wrote ...
I'm looking to buy cabling to run line-level stereo audio through the
walls of my home (tape mon output of one receiver/amp, thru walls and
into another amp). It's for an outdoor stereo so I don't need the
end-all-be-all best sound, just decent, humless audio. The most common
cabling choice seems to be Belden 9451D. Another Belden cable, 8723,
looks identical--I can't see what the difference is. Does anyone have
an opinion on which is better? I'd prefer the 8723 since I can find it
sold by the foot, the 9451D is only available in bulk.

Belden 8723: http://www.weisd.com/store2/BEL8723%20060U1000B.html

Belden 9451D: http://www.sjmediasystem.com/bl-9451d-1000.html

I would buy whatever is cheaper and/or more convenient.
It is unlikely you will experience any performance difference
between those two cable models.

There are likely even less expensive options for install-grade
shielded twisted-pair audio cable. I'm a big fan of good-old
Belden cable, but for fixed-install use at home, I'd rather
save some $$ on the cable and spend it on good balancing
transformers for each end.

Of course you ARE using balancing transformers at each
end, right? Without transformers, at least at ONE end,
you will likely run into ground-loop hum problems that
cannot be fixed with even the most expensive cable.

[toecheese]

Of course you ARE using balancing transformers at each
end, right? Without transformers, at least at ONE end,
you will likely run into ground-loop hum problems that
cannot be fixed with even the most expensive cable.


I wasn't planning on it, no. I'm not using grounded equipment, so I
figured ground loops wouldn't be an issue.

[Richard Crowley]

"toecheese" wrote ...
Of course you ARE using balancing transformers at each
end, right? Without transformers, at least at ONE end,
you will likely run into ground-loop hum problems that
cannot be fixed with even the most expensive cable.


I wasn't planning on it, no. I'm not using grounded
equipment, so I figured ground loops wouldn't be an
issue.

It has little to do with whether your equipment
is gounded or not. You might get lucky, but don't
plan on it.

Annother option that is becoming more popular
these days is using computer networking cable
("Cat5" UTP Unshielded Twisted Pair).

There are many sources of balun transformers for
both audio and video to use this inexpensive (but
super-balanced) cable. That would be my first
choice for new installations. For example...
http://www.mcmelectronics.com/product/50-7725

[toecheese]

Good to know, I'll see first if I get a hum and if so I'll try the
transformer.

using CAT5 sounds interesting, but does that give me a stereo pair or
would I need two separate CAT5 cables? As it is the Belden stereo cable
is only about $25 for the 60 foot run I need.

[Richard Crowley]

"toecheese" wrote...
Good to know, I'll see first if I get a hum and if so
I'll try the transformer.

using CAT5 sounds interesting, but does that give
me a stereo pair or would I need two separate CAT5
cables? As it is the Belden stereo cable is only about
$25 for the 60 foot run I need.

You actually get four pair in a Cat5 cable.
The advantage of Cat5 is that you can run
video (and even computer network !) over
it. The audio cable is pretty much a one-
trick pony.

75 ft of Cat5 is $11 at my local shop.
Complete with connectors already installed.

[Eeyore]

Richard Crowley wrote:

"toecheese" wrote ...
I'm looking to buy cabling to run line-level stereo audio through the
walls of my home (tape mon output of one receiver/amp, thru walls and
into another amp). It's for an outdoor stereo so I don't need the
end-all-be-all best sound, just decent, humless audio. The most common
cabling choice seems to be Belden 9451D. Another Belden cable, 8723,
looks identical--I can't see what the difference is. Does anyone have
an opinion on which is better? I'd prefer the 8723 since I can find it
sold by the foot, the 9451D is only available in bulk.

Belden 8723: http://www.weisd.com/store2/BEL8723%20060U1000B.html

Belden 9451D: http://www.sjmediasystem.com/bl-9451d-1000.html

I would buy whatever is cheaper and/or more convenient.
It is unlikely you will experience any performance difference
between those two cable models.

There are likely even less expensive options for install-grade
shielded twisted-pair audio cable. I'm a big fan of good-old
Belden cable, but for fixed-install use at home, I'd rather
save some $$ on the cable and spend it on good balancing
transformers for each end.

Of course you ARE using balancing transformers at each
end, right? Without transformers, at least at ONE end,
you will likely run into ground-loop hum problems that
cannot be fixed with even the most expensive cable.

Nonsense.

You only need a transformer at ONE end. How the heck do you think you'll get
an earth loop ?

Graham

[Eeyore]

Richard Crowley wrote:

"toecheese" wrote ...
Of course you ARE using balancing transformers at each
end, right? Without transformers, at least at ONE end,
you will likely run into ground-loop hum problems that
cannot be fixed with even the most expensive cable.


I wasn't planning on it, no. I'm not using grounded
equipment, so I figured ground loops wouldn't be an
issue.

It has little to do with whether your equipment
is gounded or not.

Yes it DOES.

Graham

[Dave Platt]

I'm looking to buy cabling to run line-level stereo audio through the
walls of my home (tape mon output of one receiver/amp, thru walls and
into another amp). It's for an outdoor stereo so I don't need the
end-all-be-all best sound, just decent, humless audio. The most common
cabling choice seems to be Belden 9451D. Another Belden cable, 8723,
looks identical--I can't see what the difference is.

The 9451D insulates the wires with polyolefin, wraps each pair of
wires in a foil shield with a drain wire, and then jackets each
shielded pair with PVC. The two shielded-and-insulated pairs are
placed side by side, in a zipcord-style arrangement.

The 8723 insulates the wires with polypropylene, wraps each pair of
insulated wires in a foil shield, places _both_ shielded wires and a
single drain wire in a single PVC outer jacket.

The 9451D might be a bit easier to terminate if you're planning to
terminate to individual RCA plugs/jackets, thanks to its zipcord-style
arrangement. The 8723 has a narrow diameter, and it might be easier
to terminate in some sort of single stereo connector.

I don't know whether one is more flexible than the other, which might
make a difference when installing.

Does anyone have an
opinion on which is better? I'd prefer the 8723 since I can find it sold
by the foot, the 9451D is only available in bulk.

In the sort of application you are considering, I don't think that
either has an electrical or sonic advantage over the other. Make the
choice for reasons of cost, availability, or convenience.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Eeyore]

toecheese wrote:

Good to know, I'll see first if I get a hum and if so I'll try the
transformer.

using CAT5 sounds interesting, but does that give me a stereo pair or
would I need two separate CAT5 cables? As it is the Belden stereo cable
is only about $25 for the 60 foot run I need.

Cat 5 gives you FOUR twisted pairs but they're unscreened (it's UTP =
unscreened twisted pair) hence you would likely need a balancing transformer
at the far end.
http://en.wikipedia.org/wiki/Category_5_cable

There's nothing special about Belden cable for your purposes btw.

Graham

[Eeyore]

Richard Crowley wrote:

"toecheese" wrote...
Good to know, I'll see first if I get a hum and if so
I'll try the transformer.

using CAT5 sounds interesting, but does that give
me a stereo pair or would I need two separate CAT5
cables? As it is the Belden stereo cable is only about
$25 for the 60 foot run I need.

You actually get four pair in a Cat5 cable.
The advantage of Cat5 is that you can run
video (and even computer network !) over
it. The audio cable is pretty much a one-
trick pony.

75 ft of Cat5 is $11 at my local shop.
Complete with connectors already installed.

And a couple of good audio transformers is probably ~ $200 !

Graham

[Dave Platt]

using CAT5 sounds interesting, but does that give me a stereo pair or
would I need two separate CAT5 cables?

CAT5 has four twisted pairs - you could carry two stereo pairs in a
single run.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Richard Crowley]

"Eeyore" wrote...
Richard Crowley wrote:

"toecheese" wrote...
Good to know, I'll see first if I get a hum and if so
I'll try the transformer.

using CAT5 sounds interesting, but does that give
me a stereo pair or would I need two separate CAT5
cables? As it is the Belden stereo cable is only about
$25 for the 60 foot run I need.

You actually get four pair in a Cat5 cable.
The advantage of Cat5 is that you can run
video (and even computer network !) over
it. The audio cable is pretty much a one-
trick pony.

75 ft of Cat5 is $11 at my local shop.
Complete with connectors already installed.

And a couple of good audio transformers is probably ~ $200 !

And I'd bet that he will need transformers (of whatever
grade) regardless of what kind of cable he uses.
Running 65 feet of cable between pieces of
consumer audio equipment in different rooms
is a standard setup for hum and similar problems.

Perhaps you missed my reference to a $35 solution.

[Eeyore]

Richard Crowley wrote:

"Eeyore" wrote...
Richard Crowley wrote:
"toecheese" wrote...

Good to know, I'll see first if I get a hum and if so
I'll try the transformer.

using CAT5 sounds interesting, but does that give
me a stereo pair or would I need two separate CAT5
cables? As it is the Belden stereo cable is only about
$25 for the 60 foot run I need.

You actually get four pair in a Cat5 cable.
The advantage of Cat5 is that you can run
video (and even computer network !) over
it. The audio cable is pretty much a one-
trick pony.

75 ft of Cat5 is $11 at my local shop.
Complete with connectors already installed.

And a couple of good audio transformers is probably ~ $200 !

And I'd bet that he will need transformers (of whatever
grade) regardless of what kind of cable he uses.
Running 65 feet of cable between pieces of
consumer audio equipment in different rooms
is a standard setup for hum and similar problems.

Not at all when there's no common mains ground connection.

Graham

[Richard Crowley]

"Eeyore" wrote ...
Richard Crowley wrote:
And I'd bet that he will need transformers (of whatever
grade) regardless of what kind of cable he uses.
Running 65 feet of cable between pieces of
consumer audio equipment in different rooms
is a standard setup for hum and similar problems.

Not at all when there's no common mains ground connection.

Your optimism is admirable and I would be very grateful
if it were accurate. Alas, it doesn't wash in my reality.
(Not to mention the numerous posts from people who
have tried it and come here asking for solutions.)
I'm willing to wait for the results of the OP's actual
implementation.

[Eeyore]

Richard Crowley wrote:

"Eeyore" wrote ...
Richard Crowley wrote:
And I'd bet that he will need transformers (of whatever
grade) regardless of what kind of cable he uses.
Running 65 feet of cable between pieces of
consumer audio equipment in different rooms
is a standard setup for hum and similar problems.

Not at all when there's no common mains ground connection.

Your optimism is admirable and I would be very grateful
if it were accurate.

I've had no trouble with that style of working myself.


Alas, it doesn't wash in my reality.
(Not to mention the numerous posts from people who
have tried it and come here asking for solutions.)
I'm willing to wait for the results of the OP's actual
implementation.

In order for there to be a ground loop there first has to be a LOOP !
The issue with laptops is something else entirely.

Graham

[Kevin McMurtrie]

In article WY6dndLx74TP4J_VnZ2dnUVZ_t6onZ2d@pcez,
"Richard Crowley" wrote:

"Eeyore" wrote...
Richard Crowley wrote:

"toecheese" wrote...
Good to know, I'll see first if I get a hum and if so
I'll try the transformer.

using CAT5 sounds interesting, but does that give
me a stereo pair or would I need two separate CAT5
cables? As it is the Belden stereo cable is only about
$25 for the 60 foot run I need.

You actually get four pair in a Cat5 cable.
The advantage of Cat5 is that you can run
video (and even computer network !) over
it. The audio cable is pretty much a one-
trick pony.

75 ft of Cat5 is $11 at my local shop.
Complete with connectors already installed.

And a couple of good audio transformers is probably ~ $200 !

And I'd bet that he will need transformers (of whatever
grade) regardless of what kind of cable he uses.
Running 65 feet of cable between pieces of
consumer audio equipment in different rooms
is a standard setup for hum and similar problems.

Perhaps you missed my reference to a $35 solution.

$15 for Cat6 and $20 left over for balancing transformers? I don't
think that would work well.

He gave links to balanced wiring. Balanced audio allows for a bit of a
grounding mismatch between equipment. If his equipment supports it,
balanced wiring is by far the cheapest and highest quality way to do
this.

--
Block Google's spam and enjoy Usenet again.
Reply with Google and I won't hear from you.

[Eeyore]

Kevin McMurtrie wrote:

"Richard Crowley" wrote:
"Eeyore" wrote...
Richard Crowley wrote:
"toecheese" wrote...

Good to know, I'll see first if I get a hum and if so
I'll try the transformer.

using CAT5 sounds interesting, but does that give
me a stereo pair or would I need two separate CAT5
cables? As it is the Belden stereo cable is only about
$25 for the 60 foot run I need.

You actually get four pair in a Cat5 cable.
The advantage of Cat5 is that you can run
video (and even computer network !) over
it. The audio cable is pretty much a one-
trick pony.

75 ft of Cat5 is $11 at my local shop.
Complete with connectors already installed.

And a couple of good audio transformers is probably ~ $200 !

And I'd bet that he will need transformers (of whatever
grade) regardless of what kind of cable he uses.
Running 65 feet of cable between pieces of
consumer audio equipment in different rooms
is a standard setup for hum and similar problems.

Perhaps you missed my reference to a $35 solution.

$15 for Cat6 and $20 left over for balancing transformers? I don't
think that would work well.

He gave links to balanced wiring. Balanced audio allows for a bit of a
grounding mismatch between equipment.

Errr ... that's not actually quite the intention per se but it would cope
with that.


If his equipment supports it, balanced wiring is by far the cheapest and
highest quality way to do
this.

Balanced wiring only gives you an advantage if the equipment is balanced.
With clever wiring it's only actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput but you need to
know what you're doing in this case.

Graham

[Arny Krueger]

"Eeyore" wrote in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage do
you get from an electronically-balanced output driving an unbalanced input?

[Don Pearce]

On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage do
you get from an electronically-balanced output driving an unbalanced input?


Provided you have an appropriate balun, like a transformer at the
input, you get all of the advantages.

d

--

d

[Serge Auckland[_2_]]

"Don Pearce" wrote in message
...
On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage
do
you get from an electronically-balanced output driving an unbalanced
input?


Provided you have an appropriate balun, like a transformer at the
input, you get all of the advantages.

d

--

d

Yes but then you're driving a balanced input aren't you ;-) If you have an
electronically balanced output (hence usually but not always referred to
ground) driving an unbalanced input, I can't see what real benefit you will
get however clever you are with wiring. What you use a balanced system for
is to get rid of common-mode noise, usually in the form of hum, but also
higher frequencies. Unbalancing at the receiving end will remove the
common-mode rejection.

If I were doing what the OP is doing, I would wire my house with CAT5/6
cable which is really cheap these days, then use equipment with balanced
I/O. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so
you either get 2 stereos or a send and return stereo pair in each cable.
Crosstalk isn't an issue with balanced operation. If suitable balanced
equipment isn't available, then there are some alternatives. Transformers
are definitely one, and they have the advantage of fully-floating operation
and galvanic insulation. However, good transformers are expensive, although
it's not necessary these days to have transformers which will drive 600 ohm
lines, 10k-10k transformers are somewhat cheaper. Other alternatives are to
get some pro units like the Henry Matchbox which lists at $225 for a
bi-directional interface, therefore equivalent to 4 transformers. I would
guess that the street price for the Matchbox is under $200 and as these
things don't wear out, it may be possible to buy these on EBay for half that
price.

Whatever way you do it, I would not even think about using unbalanced wiring
however well screened, as once incorporated in the house, it can't be
changed.


S.
--
http://audiopages.googlepages.com

[Don Pearce]

On Tue, 15 Apr 2008 13:41:20 +0100, "Serge Auckland"
wrote:

"Don Pearce" wrote in message
...
On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage
do
you get from an electronically-balanced output driving an unbalanced
input?


Provided you have an appropriate balun, like a transformer at the
input, you get all of the advantages.

d

--

d

Yes but then you're driving a balanced input aren't you ;-) If you have an
electronically balanced output (hence usually but not always referred to
ground) driving an unbalanced input, I can't see what real benefit you will
get however clever you are with wiring. What you use a balanced system for
is to get rid of common-mode noise, usually in the form of hum, but also
higher frequencies. Unbalancing at the receiving end will remove the
common-mode rejection.

You are right of course. Maplin have stereo audio transformers that
work very transparently for isolation at under £10 apiece.

http://www.maplin.co.uk/Search.aspx?...source=15&SD=Y


If I were doing what the OP is doing, I would wire my house with CAT5/6
cable which is really cheap these days, then use equipment with balanced
I/O. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so
you either get 2 stereos or a send and return stereo pair in each cable.
Crosstalk isn't an issue with balanced operation. If suitable balanced
equipment isn't available, then there are some alternatives. Transformers
are definitely one, and they have the advantage of fully-floating operation
and galvanic insulation. However, good transformers are expensive, although
it's not necessary these days to have transformers which will drive 600 ohm
lines, 10k-10k transformers are somewhat cheaper. Other alternatives are to
get some pro units like the Henry Matchbox which lists at $225 for a
bi-directional interface, therefore equivalent to 4 transformers. I would
guess that the street price for the Matchbox is under $200 and as these
things don't wear out, it may be possible to buy these on EBay for half that
price.

Whatever way you do it, I would not even think about using unbalanced wiring
however well screened, as once incorporated in the house, it can't be
changed.

CAT5 is possibly the way to go. Are you sure about the crosstalk
though? With digital signals it is only necessary to get better than
about 10dB of isolation. I would want better than 90dB for audio,
particularly if carrying unrelated signals.


--

d

[Serge Auckland[_2_]]

"Don Pearce" wrote in message
...
On Tue, 15 Apr 2008 13:41:20 +0100, "Serge Auckland"
wrote:

"Don Pearce" wrote in message
...
On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what
advantage
do
you get from an electronically-balanced output driving an unbalanced
input?


Provided you have an appropriate balun, like a transformer at the
input, you get all of the advantages.

d

--

d

Yes but then you're driving a balanced input aren't you ;-) If you have
an
electronically balanced output (hence usually but not always referred to
ground) driving an unbalanced input, I can't see what real benefit you
will
get however clever you are with wiring. What you use a balanced system for
is to get rid of common-mode noise, usually in the form of hum, but also
higher frequencies. Unbalancing at the receiving end will remove the
common-mode rejection.

You are right of course. Maplin have stereo audio transformers that
work very transparently for isolation at under £10 apiece.

http://www.maplin.co.uk/Search.aspx?...source=15&SD=Y


If I were doing what the OP is doing, I would wire my house with CAT5/6
cable which is really cheap these days, then use equipment with balanced
I/O. As already mentioned, CAT5/6 can carry 4 balanced audio signals, so
you either get 2 stereos or a send and return stereo pair in each cable.
Crosstalk isn't an issue with balanced operation. If suitable balanced
equipment isn't available, then there are some alternatives. Transformers
are definitely one, and they have the advantage of fully-floating
operation
and galvanic insulation. However, good transformers are expensive,
although
it's not necessary these days to have transformers which will drive 600
ohm
lines, 10k-10k transformers are somewhat cheaper. Other alternatives are
to
get some pro units like the Henry Matchbox which lists at $225 for a
bi-directional interface, therefore equivalent to 4 transformers. I would
guess that the street price for the Matchbox is under $200 and as these
things don't wear out, it may be possible to buy these on EBay for half
that
price.

Whatever way you do it, I would not even think about using unbalanced
wiring
however well screened, as once incorporated in the house, it can't be
changed.

CAT5 is possibly the way to go. Are you sure about the crosstalk
though? With digital signals it is only necessary to get better than
about 10dB of isolation. I would want better than 90dB for audio,
particularly if carrying unrelated signals.


--

d


I haven't measured the crosstalk using CAT5 cable myself, but I know of
several radio stations that use unscreened multi-twisted-pair bundles for
line-level analogue audio and have no crosstalk issues(The multi-pair cables
have one overall screen, but the individual pairs are unscreened.) The
twisted pairs in CAT5 cable are pretty tightly twisted, and using today's
low output impedance sending, (typically less than 100 ohms) I would not
expect cross talk with line-level signals to be a problem. Clearly, I
wouldn't use CAT5 cable for microphone feeds, but for line-level I would
expect it to be fine.

S.
--
http://audiopages.googlepages.com

[Richard Crowley]

"Kevin McMurtrie" wrote ...
$15 for Cat6 and $20 left over for balancing transformers?
I don't think that would work well.

Actually, growing numbers of people find it ideal.

He gave links to balanced wiring. Balanced audio allows for a bit of
a
grounding mismatch between equipment. If his equipment supports it,
balanced wiring is by far the cheapest and highest quality way to do
this.

1) The OP was asking about wiring his consumer audio
equipment. The likelyhood that it has balanced inputs or
outputs lies somewhere between slim and none.

2) Cat5 (et.al.) *IS* balanced. In fact, it is balanced much
better than most any cable sold for audio purposes.

[Arny Krueger]

"Don Pearce" wrote in message

On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote
in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give,
but what advantage do you get from an
electronically-balanced output driving an unbalanced
input?


Provided you have an appropriate balun, like a
transformer at the input, you get all of the advantages.

The balun just turns the unbalanced input into a balanced input. Therefore,
the basic answer I asked has not been answered.

[Don Pearce]

On Tue, 15 Apr 2008 09:39:00 -0400, "Arny Krueger"
wrote:

"Don Pearce" wrote in message

On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote
in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give,
but what advantage do you get from an
electronically-balanced output driving an unbalanced
input?


Provided you have an appropriate balun, like a
transformer at the input, you get all of the advantages.

The balun just turns the unbalanced input into a balanced input. Therefore,
the basic answer I asked has not been answered.


Ah - ok. The answer to your question is that it is impossible to drive
an unbalanced input from a balanced output. The moment any part of the
system is unbalanced, the whole system is unbalanced.

d

--

d

[Arny Krueger]

"Serge Auckland" wrote in
message

If I were doing what the OP is doing, I would wire my
house with CAT5/6 cable which is really cheap these days,
then use equipment with balanced I/O.

Sounds like a plan.

As already
mentioned, CAT5/6 can carry 4 balanced audio signals, so
you either get 2 stereos or a send and return stereo pair
in each cable. Crosstalk isn't an issue with balanced
operation.

Well, far less of an issue. Low impedance operation also favor low
crosstalk.

If suitable balanced equipment isn't
available, then there are some alternatives. Transformers
are definitely one, and they have the advantage of
fully-floating operation and galvanic insulation.

Agreed.

However, good transformers are expensive, although it's
not necessary these days to have transformers which will
drive 600 ohm lines, 10k-10k transformers are somewhat
cheaper.

I did some tests on the pair of transformers that RS is selling as a ground
isolator, for the princely sum of $16.99 or so. They turned out to be very
good, especially if you keep their secondaries loaded with a few K.

http://www.radioshack.com/sm-buy-the...i-2062214.html

I tested Radio Shack's "Ground Isolator" 270-054 using
test signals that maxed out around 2.5 v RMS. ZSource = 150 ohms, ZLoad =
10K ohms.

All IM, THD, and noise artifacts were at least 80 dB down with most in
the -100 dB range or better. Frequency response showed a 2 dB peak at 20 Hz
and then 10 dB down at 10 Hz. There was a 3 dB peak at about 51 KHz falling
to about 10 dB down around 100 KHz. +0.5 dB at 20 KHz. A little more
resistive loading tames both peaks.

[Arny Krueger]

"Don Pearce" wrote in message

On Tue, 15 Apr 2008 09:39:00 -0400, "Arny Krueger"
wrote:

"Don Pearce" wrote in message

On Tue, 15 Apr 2008 07:52:51 -0400, "Arny Krueger"
wrote:

"Eeyore" wrote
in
message

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or
ouput but you need to know what you're doing in this
case.

I know the strong advantage that balanced inputs give,
but what advantage do you get from an
electronically-balanced output driving an unbalanced
input?


Provided you have an appropriate balun, like a
transformer at the input, you get all of the advantages.

The balun just turns the unbalanced input into a
balanced input. Therefore, the basic answer I asked has
not been answered.


Ah - ok. The answer to your question is that it is
impossible to drive an unbalanced input from a balanced
output.

Good, then I'm not losing my mind! ;-)


The moment any part of the system is unbalanced,
the whole system is unbalanced.

As a practical matter, an unbalanced output driving a balanced input can
have most of the benefits of a completely balanced system. One step up is
the so-called impedance balanced output, which involves adding a single
resistor to the source. That usually gives you over 90% of the benefits of
a completely balanced output.

[Eeyore]

Arny Krueger wrote:

"Eeyore" wrote

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage do
you get from an electronically-balanced output driving an unbalanced input?

The elimination of a common ground connection that can cause circulating
currents in a signal conductor in the unbalanced circuit (in the screen) because
in unbalanced working the screen is used as a signal conductor as well and a
voltage will be added to the signal (of magnitude RDCscreen x Iground loop).
That's a circulating current as in a loop hence ground loop.

The voltage added may actually be larger than that if poor internal grounding
stategies have been used in the equipment under consideration due to RDC of pcb
traces before the ground loop current finds it way to 'chassis earth' too.

Graham

[Eeyore]

Don Pearce wrote:

"Arny Krueger" wrote:
"Eeyore" wrote in

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage do
you get from an electronically-balanced output driving an unbalanced input?


Provided you have an appropriate balun, like a transformer at the
input, you get all of the advantages.

You don't even need a balun if you wire it to take advantage of the balanced
output. Just take the balaned output (low/cold) to the destination input 'ground'
and the output (high/hot) to the destination input and do not connect the screen
at the destination.

Graham

[Eeyore]

Don Pearce wrote:

"Arny Krueger" wrote:

The balun just turns the unbalanced input into a balanced input. Therefore,
the basic answer I asked has not been answered.

Ah - ok. The answer to your question is that it is impossible to drive
an unbalanced input from a balanced output. The moment any part of the
system is unbalanced, the whole system is unbalanced.

Pure unmitigated horse manure ! See my post as to how it's done. Sadly most
people don't understand balanced circuits at all. Think *differential* and it
may become clearer.

I recently did just what you say can't be done for an install. Much improved.

Graham

[Eeyore]

Arny Krueger wrote:

"Don Pearce" wrote in message

Ah - ok. The answer to your question is that it is
impossible to drive an unbalanced input from a balanced
output.

Good, then I'm not losing my mind! ;-)

Don is talking CRAP unfortunately.

Graham

[Eeyore]

Richard Crowley wrote:

"Kevin McMurtrie" wrote ...
$15 for Cat6 and $20 left over for balancing transformers?
I don't think that would work well.

Actually, growing numbers of people find it ideal.

He gave links to balanced wiring. Balanced audio allows for a bit of
a grounding mismatch between equipment. If his equipment supports it,
balanced wiring is by far the cheapest and highest quality way to do
this.

1) The OP was asking about wiring his consumer audio
equipment. The likelyhood that it has balanced inputs or
outputs lies somewhere between slim and none.

I agree. OTOH it's VERY likely to be Class II equipment so the possibility
of a ground loop doesn't arise unless through other equipment attached to
it that does connect to the mains earth.

Graham

[Eeyore]

Serge Auckland wrote:

Whatever way you do it, I would not even think about using unbalanced wiring
however well screened, as once incorporated in the house, it can't be
changed.

For little more you can run screened twin and keep your options open. That's
probably the best advice. Cat 5 can cause crosstalk trouble.

Graham

[Eeyore]

Serge Auckland wrote:

"Don Pearce" wrote in message

CAT5 is possibly the way to go. Are you sure about the crosstalk
though? With digital signals it is only necessary to get better than
about 10dB of isolation. I would want better than 90dB for audio,
particularly if carrying unrelated signals.


I haven't measured the crosstalk using CAT5 cable myself, but I know of
several radio stations that use unscreened multi-twisted-pair bundles for
line-level analogue audio and have no crosstalk issues.

But they WILL be running balanced circuits ! I don't see Cat5 as a suitable
choice here at all when ordinary screened twisted pair (balanced) cable doesn't
cost a fortune.

Graham

[Serge Auckland[_2_]]

"Eeyore" wrote in message
...


Don Pearce wrote:

"Arny Krueger" wrote:

The balun just turns the unbalanced input into a balanced input.
Therefore,
the basic answer I asked has not been answered.

Ah - ok. The answer to your question is that it is impossible to drive
an unbalanced input from a balanced output. The moment any part of the
system is unbalanced, the whole system is unbalanced.

Pure unmitigated horse manure ! See my post as to how it's done. Sadly
most
people don't understand balanced circuits at all. Think *differential* and
it
may become clearer.

I recently did just what you say can't be done for an install. Much
improved.

Graham


Balancing requires exactly that, that the circuits be balanced to ground:-
same impedance, i.e. same capacitance, inductance etc. That, and
differential inputs provides the common-mode rejection that keeps signals
clean of lf (hum) and higher frequencies. A differential input that isn't
balanced will have poor common-mode rejection, so although it will reduce
some interference, it most probably won't do it at higher frequencies.

The system you advocate won't work with equipment where the audio ground is
also taken to proper ground, and therefore is dependant on the actual
details of the equipment used. As far as I'm concerned, if I'm taking audio
cables more than about 10 metres, I balance properly.

As to the use of CAT5 cable, whilst I agree with you that potentially there
is an issue with crosstalk, my experience professionally in several radio
stations, is that it's perfectly acceptable. As I said in an earlier post, I
have not measured the crosstalk myself, but I'm in the process of installing
some audio cabling using CAT5, so I may be in a position to post some
measurements later.

S.
--
http://audiopages.googlepages.com

[Don Pearce]

On Tue, 15 Apr 2008 18:26:51 +0100, Eeyore
wrote:



Arny Krueger wrote:

"Don Pearce" wrote in message

Ah - ok. The answer to your question is that it is
impossible to drive an unbalanced input from a balanced
output.

Good, then I'm not losing my mind! ;-)

Don is talking CRAP unfortunately.

Graham

Only when the following subsequent is deleted. One unbalanced
connection unbalances the entire circuit.


--

d

[Don Pearce]

On Tue, 15 Apr 2008 18:23:49 +0100, Eeyore
wrote:



Don Pearce wrote:

"Arny Krueger" wrote:
"Eeyore" wrote in

Balanced wiring only gives you an advantage if the
equipment is balanced. With clever wiring it's only
actually necessary for either the 'sending' or
'receiving' equipment to have a balanced input or ouput
but you need to know what you're doing in this case.

I know the strong advantage that balanced inputs give, but what advantage do
you get from an electronically-balanced output driving an unbalanced input?


Provided you have an appropriate balun, like a transformer at the
input, you get all of the advantages.

You don't even need a balun if you wire it to take advantage of the balanced
output. Just take the balaned output (low/cold) to the destination input 'ground'
and the output (high/hot) to the destination input and do not connect the screen
at the destination.

Graham

No longer balanced - not even a tiny bit.

--

d

[Serge Auckland[_2_]]

"Eeyore" wrote in message
...


Serge Auckland wrote:

"Don Pearce" wrote in message

CAT5 is possibly the way to go. Are you sure about the crosstalk
though? With digital signals it is only necessary to get better than
about 10dB of isolation. I would want better than 90dB for audio,
particularly if carrying unrelated signals.


I haven't measured the crosstalk using CAT5 cable myself, but I know of
several radio stations that use unscreened multi-twisted-pair bundles for
line-level analogue audio and have no crosstalk issues.

But they WILL be running balanced circuits ! I don't see Cat5 as a
suitable
choice here at all when ordinary screened twisted pair (balanced) cable
doesn't
cost a fortune.

Graham



I have assumed that the OP will run balanced, either through transformers or
whatever. The beauty of CAT5 is not just the cost, but that you get two
stereo circuits in one cable. That gives options like send and return, or
one stereo pair with a mono cue return and a control pair, or two stereo
sends. All that at a cost less than one length of screened twisted-pair.

S.

--
http://audiopages.googlepages.com

[Eeyore]

Don Pearce wrote:

Eeyore wrote:
Arny Krueger wrote:
"Don Pearce" wrote in message

Ah - ok. The answer to your question is that it is
impossible to drive an unbalanced input from a balanced
output.

Good, then I'm not losing my mind! ;-)

Don is talking CRAP unfortunately.


Only when the following subsequent is deleted. One unbalanced
connection unbalances the entire circuit.

Read what I posted carefully. I AM correct.

Balanced is somewhat different to differential in detail and one or the
other may be equally suitable as a 'hum reducing' strategy.

Graham