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Bikedrd Bikedrd is offline
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Default RCA cable question

I wonder if there is some trick I can use, and I if someone out there
can help me.

I recently bought a house that someone had wired a remote speakers
into (for their surround sound).

I don't plan to use the surround sound; however, I do have my
traditional stereo amplifier at one end of one remote speaker wire and
my TV at the other end.

What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?

Is it possible to run both hots using the speaker wire and use the
home electrical system for ground? If so, would it sound like crap
because the wires would not be shielded?

Any ideas out there?

Thanks
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David Nebenzahl David Nebenzahl is offline
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Default RCA cable question

On 2/21/2010 2:09 PM Bikedrd spake thus:

I wonder if there is some trick I can use, and I if someone out there
can help me.

I recently bought a house that someone had wired a remote speakers
into (for their surround sound).

I don't plan to use the surround sound; however, I do have my
traditional stereo amplifier at one end of one remote speaker wire and
my TV at the other end.

What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?


The answer is, it depends. On how long the run of wire is, just how
badly shielded it is and what possible interference sources it runs by.

Easy enough to find out, though: why don't you just try it and see? If
you do, instead of checking it with a signal, power everything up and
turn the volume up without any signal (sat receiver tuned to nothing or
output muted) to see how much hum and noise you're picking up.

Is it possible to run both hots using the speaker wire and use the
home electrical system for ground? If so, would it sound like crap
because the wires would not be shielded?


No. No no no no NO! Please don't even attempt this.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
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Tomi Holger Engdahl[_3_] Tomi Holger Engdahl[_3_] is offline
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Default RCA cable question

Bikedrd writes:

I wonder if there is some trick I can use, and I if someone out there
can help me.

I recently bought a house that someone had wired a remote speakers
into (for their surround sound).

I don't plan to use the surround sound; however, I do have my
traditional stereo amplifier at one end of one remote speaker wire and
my TV at the other end.

What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?


Single speaker wire pair is not a good match for stereo audio
signals. Basically you would need at least three wires to
properly transmit the stereo signal (left, right , ground).
And the cable should be shielded type to keep noise out.
Unshielded cable can work in some short runs without picking
too much interference if you are lucky... usually you get noise
you can hear.

Is it possible to run both hots using the speaker wire and use the
home electrical system for ground? If so, would it sound like crap
because the wires would not be shielded?


Running two hots using speaker wire and using home electrical system
for ground is not a solution that would work acceptably, most
propable yoy get so much noise to sound that the wiring like this
woudl give you more noise than sound... and you risk damaging
equipment (there can be consierable voltage difference between
two points in electrical systel grounds inside building.

The voltage difference between two outlets would give you
most propably horrible amount of humming noise, plus you
would hear light switches turning on/off and equipment making noises
to electrical wiring..
Also she unshielded cables wired far away from the ground
connection would also pick up lots of noise from any
electrical noise source nearby. This kind of wiring would
be very sensitive to pick noise with both magnetic inductive
and electrical fields capacitively coupling to wiring.

Any ideas out there?
Thanks


Pull new suitable wiring inside wall using the old speaker wire
to pull in the new cable... Or just pull new cable and leave the
old one unused. Or consider some wireless audio transmission solutions.

--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
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Richard Crowley Richard Crowley is offline
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Default RCA cable question

"Bikedrd" wrote ...
What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?


Do you have digital audio output on the satellite receiver?
(Either an SPDIF optical port or an orange RCA jack.)
And a digital input on your receiver? You could make the
digital signal into a super-balanced feed and receive it with a
balanced digital receiver on the other end. It wouldn't require
shielding OR ground reference.

You would need to do some experimenting to discover the
impedance of the speaker wire, and likely hack together a
little 1-chip circuit at each end. But this is a common solution
and there are ample application diagrams for the circuit.

Is it possible to run both hots using the speaker wire and use the
home electrical system for ground? If so, would it sound like crap
because the wires would not be shielded?


No, absolutely not. Don't even think about doing this.


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David Nebenzahl David Nebenzahl is offline
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Default RCA cable question

On 2/22/2010 10:24 AM Richard Crowley spake thus:

"Bikedrd" wrote ...

What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?


Do you have digital audio output on the satellite receiver?
(Either an SPDIF optical port or an orange RCA jack.)
And a digital input on your receiver? You could make the
digital signal into a super-balanced feed and receive it with a
balanced digital receiver on the other end. It wouldn't require
shielding OR ground reference.

You would need to do some experimenting to discover the
impedance of the speaker wire, and likely hack together a
little 1-chip circuit at each end. But this is a common solution
and there are ample application diagrams for the circuit.


Do you happen to have any links to such diagrams handy? I'm curious
about this as well.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"


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Richard Crowley Richard Crowley is offline
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Default RCA cable question

"David Nebenzahl" wrote ...
Richard Crowley spake thus:
"Bikedrd" wrote ...
What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?


Do you have digital audio output on the satellite receiver?
(Either an SPDIF optical port or an orange RCA jack.)
And a digital input on your receiver? You could make the
digital signal into a super-balanced feed and receive it with a
balanced digital receiver on the other end. It wouldn't require
shielding OR ground reference.

You would need to do some experimenting to discover the
impedance of the speaker wire, and likely hack together a
little 1-chip circuit at each end. But this is a common solution
and there are ample application diagrams for the circuit.


Do you happen to have any links to such diagrams handy? I'm curious about
this as well.


Look at the application circuits for high-speed differential
drivers like Maxim MAX4447, 4448, 4449 and the
corresponding recivers like Maxim MAX4144, 4145.
There are many similar products from Maxim and others.

If they can send video over twisted pair phone wiring, they
can surely send digital audio over an old ratty speaker pair.

For that matter, there are ICs and circuits specifically for
driving 110-ohm twisted pair AES/EBU audio. Those
could likely be pressed into service for something like this.


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pandama pandama is offline
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Default RCA cable question

Bike, there is a trick, but don't be an idiot. Buy 50 metres of high
quality wire, at least 3 core. Tie this onto one end of the wire already in
your house. Pull the old wire out from the other end until the new wiring
comes out. This way you can install high quality new wiring.





















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David Nebenzahl David Nebenzahl is offline
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Default RCA cable question

On 2/23/2010 10:38 PM pandama spake thus:

Bike, there is a trick, but don't be an idiot. Buy 50 metres of high
quality wire, at least 3 core. Tie this onto one end of the wire already in
your house. Pull the old wire out from the other end until the new wiring
comes out. This way you can install high quality new wiring.


Well, that'll work *unless* the speaker wire is stapled somewhere to
something, is kinked, goes through a small hole and gets knotted, etc.,
etc. If you start pulling on it and it gets stuck halfway through,
you're screwed.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
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Tomi Holger Engdahl[_3_] Tomi Holger Engdahl[_3_] is offline
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Default RCA cable question

"Richard Crowley" writes:

"David Nebenzahl" wrote ...
Richard Crowley spake thus:
"Bikedrd" wrote ...
What I am wondering is: is there a way to use the single speaker wire
pair to transmit line-level RCA audio output from my satellite
receiver to an input on my amp?

Do you have digital audio output on the satellite receiver?
(Either an SPDIF optical port or an orange RCA jack.)
And a digital input on your receiver? You could make the
digital signal into a super-balanced feed and receive it with a
balanced digital receiver on the other end. It wouldn't require
shielding OR ground reference.

You would need to do some experimenting to discover the
impedance of the speaker wire, and likely hack together a
little 1-chip circuit at each end. But this is a common solution
and there are ample application diagrams for the circuit.


Do you happen to have any links to such diagrams handy? I'm curious about
this as well.


Look at the application circuits for high-speed differential
drivers like Maxim MAX4447, 4448, 4449 and the
corresponding recivers like Maxim MAX4144, 4145.
There are many similar products from Maxim and others.

If they can send video over twisted pair phone wiring, they
can surely send digital audio over an old ratty speaker pair.


Yes. One idea that coudl be worth of try is to check if some
ready made cheap video to UPD adapter would work on the conversion.
The S/PDIF signal is 75 ohms and on same frequency and signal level
range as video signals, so a video balun would be a good match
for converting spdif to balanced signal and back.

For that matter, there are ICs and circuits specifically for
driving 110-ohm twisted pair AES/EBU audio. Those
could likely be pressed into service for something like this.


The driver and receiver for 110-owh AES/EBU is practically
same as used in RS-485. So check the RS-485 component for this.

Some SPDIF information and related circuits can be found at
http://www.epanorama.net/documents/audio/spdif.html

--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
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Arny Krueger Arny Krueger is offline
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Default RCA cable question

"Bikedrd" wrote in message

I wonder if there is some trick I can use, and I if
someone out there can help me.

I recently bought a house that someone had wired a remote
speakers into (for their surround sound).

I don't plan to use the surround sound; however, I do
have my traditional stereo amplifier at one end of one
remote speaker wire and my TV at the other end.

What I am wondering is: is there a way to use the single
speaker wire pair to transmit line-level RCA audio output
from my satellite receiver to an input on my amp?


Convert it to SP/DIF (digital) and use a pair of baluns to match up 75 ohm
unbalanced (SPDIF) to your speaker wire which is probably best thought of as
being twisted pair.

Is it possible to run both hots using the speaker wire
and use the home electrical system for ground?


Possibly, if you are talking about using the safety ground of your house
wiring as your ground. If you're talking about using neutral, forget it.
Unsafe!

If so, would it sound like crap because the wires would not be
shielded?


Probably not, if you can avoid grounding problems. Your biggest problems are
avoiding setting up something that is unsafe and/or full of hum.

Any ideas out there?

Thanks





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David Nebenzahl David Nebenzahl is offline
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Default RCA cable question

On 2/25/2010 5:35 AM Arny Krueger spake thus:

"Bikedrd" wrote in message


Is it possible to run both hots using the speaker wire
and use the home electrical system for ground?


Possibly, if you are talking about using the safety ground of your house
wiring as your ground. If you're talking about using neutral, forget it.
Unsafe!


BZZZZZT! Wrong!

While using the power line's neutral would be suicidal, even using the
so-called "ground" conductor would be flirting with suicide, or at least
very bad results. The chance that the "ground" conductor is actually at
0 volts is vanishingly small.

The rule to follow here is don't mix signal and power circuits, ever, at
all.


--
You were wrong, and I'm man enough to admit it.

- a Usenet "apology"
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Richard Crowley Richard Crowley is offline
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Default RCA cable question

"David Nebenzahl" wrote ...
Arny Krueger spake thus:
"Bikedrd" wrote
Is it possible to run both hots using the speaker wire
and use the home electrical system for ground?


Possibly, if you are talking about using the safety ground of your house
wiring as your ground. If you're talking about using neutral, forget it.
Unsafe!


BZZZZZT! Wrong!

While using the power line's neutral would be suicidal, even using the
so-called "ground" conductor would be flirting with suicide, or at least
very bad results. The chance that the "ground" conductor is actually at 0
volts is vanishingly small.

The rule to follow here is don't mix signal and power circuits, ever, at
all.
--
You were wrong, and I'm man enough to admit it.
- a Usenet "apology"


I don't think Mr. Krueger thought about all the ramifications of his advice.
In this case Mr. Nebenzahl's sig line was right on! :-)


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Arny Krueger Arny Krueger is offline
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Default RCA cable question

"David Nebenzahl" wrote in message
.com
On 2/25/2010 5:35 AM Arny Krueger spake thus:

"Bikedrd" wrote in message


Is it possible to run both hots using the speaker wire
and use the home electrical system for ground?


Possibly, if you are talking about using the safety
ground of your house wiring as your ground. If you're
talking about using neutral, forget it. Unsafe!


BZZZZZT! Wrong!

While using the power line's neutral would be suicidal,
even using the so-called "ground" conductor would be
flirting with suicide, or at least very bad results. The
chance that the "ground" conductor is actually at 0 volts
is vanishingly small.



Assertions are easy, but finding proof may be difficult or impossible.

I'm calling your bluff.

The rule to follow here is don't mix signal and power circuits, ever, at
all.


Safety ground is often connected to the chassis of audio gear. Signal ground
is often connected to the same chassis. Sometimes there is a switch to make
that connection optional or indirect. IOW, mixing signal ground and power
ground is often unavoidable.


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Mr.T Mr.T is offline
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Default RCA cable question


"Arny Krueger" wrote in message
...
Safety ground is often connected to the chassis of audio gear. Signal

ground
is often connected to the same chassis. Sometimes there is a switch to

make
that connection optional or indirect. IOW, mixing signal ground and power
ground is often unavoidable.


Yep, until recent years when double insulated equipment became common,
nearly all audio gear sold here had the signal grounds and safety ground
both tied to the chassis.

MrT.


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GregS[_3_] GregS[_3_] is offline
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Default RCA cable question

In article , "Mr.T" MrT@home wrote:

"Arny Krueger" wrote in message
m...
Safety ground is often connected to the chassis of audio gear. Signal

ground
is often connected to the same chassis. Sometimes there is a switch to

make
that connection optional or indirect. IOW, mixing signal ground and power
ground is often unavoidable.


Yep, until recent years when double insulated equipment became common,
nearly all audio gear sold here had the signal grounds and safety ground
both tied to the chassis.

MrT.



Its still great to tie ground to chassis. It was never good to tie signal common to chassis except
for extreme RF shielding purposes. As far as I know, all computers have the signal ground
tied to chassis and AC ground, probably includes all laptops.

greg


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Mr.T Mr.T is offline
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Default RCA cable question


"GregS" wrote in message
...
As far as I know, all computers have the signal ground
tied to chassis and AC ground, probably includes all laptops.


All the laptops I've seen use a double insulted DC power adapter with no AC
ground at all.

MrT.


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Richard Crowley Richard Crowley is offline
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Default RCA cable question

"Mr.T" MrT@home wrote...
All the laptops I've seen use a double insulted DC power adapter with no
AC
ground at all.


Several laptop power supplies (notably several Dell models)
use full 3-wire grounded power cords and apparently extend
the green-wire safety ground through to the computer power.


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Mr.T Mr.T is offline
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Default RCA cable question


"Richard Crowley" wrote in message
...
Several laptop power supplies (notably several Dell models)
use full 3-wire grounded power cords and apparently extend
the green-wire safety ground through to the computer power.


Maybe so, but it isn't all that common a practice IME.

MrT.


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Richard Crowley Richard Crowley is offline
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Default RCA cable question

"Mr.T" wrote ...
"Richard Crowley"wrote ...
Several laptop power supplies (notably several Dell models)
use full 3-wire grounded power cords and apparently extend
the green-wire safety ground through to the computer power.


Maybe so, but it isn't all that common a practice IME.


An informal survey of the stuff at home and in the office shows
more than half use 3-wire "brick" power supplies. Maybe it has
something to do with safety requirements in various countries.


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Arny Krueger Arny Krueger is offline
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"Mr.T" MrT@home wrote in message
u
"Richard Crowley" wrote in message
...
Several laptop power supplies (notably several Dell
models) use full 3-wire grounded power cords and
apparently extend the green-wire safety ground through
to the computer power.


Maybe so, but it isn't all that common a practice IME.


I just checked 2 Dell and 1 HP laptop power supplies - all computers less
than 3 years old.

All 3 had essentially dead shorts from the ground pin on the power cord to
the shell of the coaxial power plug that goes into the PC.

This seems to be how laptops have been built for the last few years. I have
some laptops with 2-wire power cords, but they are older.




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Mr.T Mr.T is offline
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Default RCA cable question


"Richard Crowley" wrote in message
...
An informal survey of the stuff at home and in the office shows
more than half use 3-wire "brick" power supplies. Maybe it has
something to do with safety requirements in various countries.


That would very likely be the case then I imagine. I should add that many of
the supplies here do have a 3 pin plug, but the ground pin is rarely
connected IME. In fact the two I have here at the moment both use a 3 pin
male to 2 pin female "figure 8" lead plugged into the power brick. All the
desktops I have used do have an earthed power supply however.

MrT.


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