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Guest
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 Posted:
Sat Oct 22, 2005 4:42 am Post subject:
Convert rca to coaxial - audio only |
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I have seen many posts on converting video/audio from RCa to coax. I
want to use existing coaxial in my house to carry an audio only signal.
This will be going from my PC's sound card RCA jacks to coaxial in the
wall to RCA jacks on my receiver.
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Guest
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| Posted:
Sat Oct 22, 2005 4:42 am Post subject:
Re: Convert rca to coaxial - audio only |
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On 2005-10-22, michaeljc70@hotmail.com <michaeljc70@hotmail.com> wrote:
| Quote: | I have seen many posts on converting video/audio from RCa to coax. I
want to use existing coaxial in my house to carry an audio only signal.
This will be going from my PC's sound card RCA jacks to coaxial in the
wall to RCA jacks on my receiver.
Adapters are available at Radio Shack to convert the cable terminal to a |
rca terminal type. |
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Richard Crowley
Guest
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| Posted:
Sat Oct 22, 2005 9:51 am Post subject:
Re: Convert rca to coaxial - audio only |
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michaeljc70 wrote ...
| Quote: | I have seen many posts on converting video/audio from RCa to coax.
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Please clarify. "RCA" is one of several kinds of coaxial connectors.
"Coax" is a broad, nearly generic, type of cable.
| Quote: | I want to use existing coaxial in my house to carry an audio
only signal. This will be going from my PC's sound card RCA
jacks to coaxial in the wall to RCA jacks on my receiver.
|
What kind of connectors does your cable have on it now? |
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Gary A. Edelstein
Guest
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| Posted:
Sat Oct 22, 2005 7:50 pm Post subject:
Re: Convert rca to coaxial - audio only |
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On 21 Oct 2005 18:04:36 -0700, michaeljc70@hotmail.com wrote:
| Quote: | I have seen many posts on converting video/audio from RCa to coax. I
want to use existing coaxial in my house to carry an audio only signal.
This will be going from my PC's sound card RCA jacks to coaxial in the
wall to RCA jacks on my receiver.
Clarify please. If you want to pass analog mono sound it's a snap. |
Just use a y-jack combiner to combine the stereo out from the PC and
adapt that to a 75 ohm f-connector. Then do the same at the other end
to hook up to the receiver. All parts are available at a place like
Radio Shack and should be less than $15-$20.
PC: Stereo mini plug to L/R analog phono (RCA) jack then phono jacks
to y-connector combiner with the combiner phono plug adapted to
f-connector.
Receiver: F-connector to phono plug adaptor to phono plug y-jack then
y-jack dual outs to receiver.
If you want stereo that's going to be a lot harder and more expensive
if you only have a single 75 ohm cable.
I think there are wi-fi solutions for this too. Gary E
--
|Gary A. Edelstein
|edelsgNO@SPAMyahoo.com.invalid (remove NO SPAM and .invalid to reply)
|"We have met the enemy and he is us." - Walt Kelly's Pogo |
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Guest
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| Posted:
Sun Oct 23, 2005 7:59 pm Post subject:
Re: Convert rca to coaxial - audio only |
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That's what I was afraid of. So, it seems there is no easy way to
carry the left and right channel on one coaxial. I would need 2
coaxial with adapters on each end which I don't have in the wall. May
just have to put a cheap PC in my media closet as I want to use a PC to
play mp3s through my whole house audio. I currently use a stand-alone
networked player, but want something more sophisticated (going to use
PocketPC to control queue, etc.).
Gary A. Edelstein wrote:
| Quote: | On 21 Oct 2005 18:04:36 -0700, michaeljc70@hotmail.com wrote:
I have seen many posts on converting video/audio from RCa to coax. I
want to use existing coaxial in my house to carry an audio only signal.
This will be going from my PC's sound card RCA jacks to coaxial in the
wall to RCA jacks on my receiver.
Clarify please. If you want to pass analog mono sound it's a snap.
Just use a y-jack combiner to combine the stereo out from the PC and
adapt that to a 75 ohm f-connector. Then do the same at the other end
to hook up to the receiver. All parts are available at a place like
Radio Shack and should be less than $15-$20.
PC: Stereo mini plug to L/R analog phono (RCA) jack then phono jacks
to y-connector combiner with the combiner phono plug adapted to
f-connector.
Receiver: F-connector to phono plug adaptor to phono plug y-jack then
y-jack dual outs to receiver.
If you want stereo that's going to be a lot harder and more expensive
if you only have a single 75 ohm cable.
I think there are wi-fi solutions for this too. Gary E
--
|Gary A. Edelstein
|edelsgNO@SPAMyahoo.com.invalid (remove NO SPAM and .invalid to reply)
|"We have met the enemy and he is us." - Walt Kelly's Pogo |
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Guest
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| Posted:
Sun Oct 23, 2005 8:02 pm Post subject:
Re: Convert rca to coaxial - audio only |
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By coaxial, I mean the kind that runs through almost every home for TV
signal.
By RCA, I am talking about the input jacks on a stereo receiver. |
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Richard Crowley
Guest
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| Posted:
Mon Oct 24, 2005 4:42 am Post subject:
Re: Convert rca to coaxial - audio only |
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"Geoff Wood" wrote ...
| Quote: | michaeljc70 wrote ...
By coaxial, I mean the kind that runs through almost every
home for TV signal.
By RCA, I am talking about the input jacks on a stereo receiver.
The idea is totally flawed. Such outputs and cables are
only designed to go a short distance.
|
Disagree. In my experience, 100s (or even 1000s) of feet
are not impractical in many cases. The main hazard is the
possibility of ground loops between the equipment at each
end. Cable made for TV is good for 100s of MHz. 20KHz
of audio is of no concern whatsoever.
| Quote: | Also TV coax is a totally different concept to screeened
unablance audio cable.
|
Disagree. They are, in essence, identical. "TV coax" (i.e.
cable made for RF frequencies) is merely designed for
lower loss at high frequencies, which is actually better
for audio frequencies.
| Quote: | Forget the whole idea, or look into an audio-over-cat5
LAN cable product.
|
Agree. No reasonably practical way to send two audio
signals (Left & Right stereo) over a single cable, whether
RF, or baseband audio coax. Sure, you could always
modulate the L&R onto a stereo RF signal and then
"receive" them at the other end. |
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Geoff Wood
Guest
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| Posted:
Mon Oct 24, 2005 4:42 am Post subject:
Re: Convert rca to coaxial - audio only |
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<michaeljc70@hotmail.com> wrote in message
news:1130079724.562260.28960@o13g2000cwo.googlegroups.com...
| Quote: | By coaxial, I mean the kind that runs through almost every home for TV
signal.
By RCA, I am talking about the input jacks on a stereo receiver.
|
The idea is totally flawed. Such outputs and cables are only designed to
go a short distance.
Also TV coax is a totally different concept to screeened unablance audio
cable.
Forget the whole idea, or look into an audio-over-cat5 LAN cable product.
geoff |
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Geoff Wood
Guest
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| Posted:
Mon Oct 24, 2005 1:49 pm Post subject:
Re: Convert rca to coaxial - audio only |
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"Richard Crowley" <rcrowley@xpr7t.net> wrote in message
news:11loe9sctv7pl01@corp.supernews.com...
| Quote: | "Geoff Wood" wrote ...
michaeljc70 wrote ...
By coaxial, I mean the kind that runs through almost every home for TV
signal.
By RCA, I am talking about the input jacks on a stereo receiver.
The idea is totally flawed. Such outputs and cables are only designed
to go a short distance.
Disagree. In my experience, 100s (or even 1000s) of feet are not
impractical in many cases. The main hazard is the
possibility of ground loops between the equipment at each
end. Cable made for TV is good for 100s of MHz. 20KHz
of audio is of no concern whatsoever.
|
In/out impedences of most consumer audio gear is totally unsuited for going
more that a meter of two at the most without hf drop-off.
| Quote: | Disagree. They are, in essence, identical. "TV coax" (i.e.
cable made for RF frequencies) is merely designed for
lower loss at high frequencies, which is actually better
for audio frequencies.
|
You have never seen the "screen" of an RF TV cable ? Coax cables work on a
totally different concept to screened audio cable.
| Quote: | Forget the whole idea, or look into an audio-over-cat5 LAN cable
product.
Agree. No reasonably practical way to send two audio
signals (Left & Right stereo) over a single cable, whether
RF, or baseband audio coax.
|
Or "around a house'.
geoff |
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Laurence Payne
Guest
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| Posted:
Mon Oct 24, 2005 3:39 pm Post subject:
Re: Convert rca to coaxial - audio only |
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On Mon, 24 Oct 2005 21:49:26 +1300, "Geoff Wood"
<geoff@nospam-paf.co.nz> wrote:
| Quote: | You have never seen the "screen" of an RF TV cable ? Coax cables work on a
totally different concept to screened audio cable.
|
There's a centre core, there's a screen. Does its other
characteristics preclude it from being used as simple screened cable
for audio? |
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Tomi Holger Engdahl
Guest
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| Posted:
Mon Oct 24, 2005 3:48 pm Post subject:
Re: Convert rca to coaxial - audio only |
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"Geoff Wood" <geoff@nospam-paf.co.nz> writes:
| Quote: | michaeljc70@hotmail.com> wrote in message
news:1130079724.562260.28960@o13g2000cwo.googlegroups.com...
By coaxial, I mean the kind that runs through almost every home for TV
signal.
By RCA, I am talking about the input jacks on a stereo receiver.
The idea is totally flawed. Such outputs and cables are only designed to
go a short distance.
|
It is not toattly flawed. Generally the RCA jacks on the equipment
are designed to drive short cables, all work there well.
Some equipment perform well even with long cables, say 10-20 meters
without considerable problems (and longer distances with some
low frequency loss).
The output impedance on the soudn source has the greatest effect
on how long cable you can run. The output impedance on different
equipment can have vatiotion of more than 1:100 (usually in 30 ohms
to 5 kilo-ohms range). The lower the output impedance, the less
effect the cable capacitance has and less sensitve the cable
is for noise pickup (at least for capacitively coupling noise).
| Quote: | Also TV coax is a totally different concept to screeened unablance audio
cable.
|
The actual cable used for TV coax and the cable used for
unablance audio cable are not entirely different concepts.
The cable construction used is the same. There is a center
wire, insulator, outer shield and insulator over it.
This same construction applies for for unbalanced audio
cables and TV coax. Those both cables have coaxial construction.
The unablanced audio cable is a cable optimized for audio applications.
It is designed to perform well on audio frequency (reasonable
cable capacitance, reasonable inaulation material, copper conductors) and
usually designed to be convient to use (flexible and not to thick).
The TV coax is a cable optimized to carry RF signals of several
hundred MHz with low loss and have right characteristic impedance
for the application (75 ohms). To make right impedance
and low loss, the cable geometry (right ratio of center connector
and outer shield innter diameter throughout the cable) and suitable
insulation material (suitable plastic or foamed plastic typically).
The cable hss good outer shield, nowadays typically consisting of
foil + braid (doubly shielded cable).
You can use a TV coax cable material to make audio cables,
jus solder the RCA cables on the end. If you have a good quality
doulby shielded cable that uses copper conductors, it
will perform well as audio interconnection cable.
You don't need to worry about the "75 ohms" label on the coax,
this impedance has nothign to do the cable properties on the
audio frequencies (unless your cable is many kilometers long!).
| Quote: | Forget the whole idea, or look into an audio-over-cat5 LAN cable product.
|
Those audio-over-cat5 LAN cable products are a good option if you have
CAT5 wiring installed.
--
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
Guest
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| Posted:
Mon Oct 24, 2005 5:43 pm Post subject:
Re: Convert rca to coaxial - audio only |
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"Laurence Payne" <lpayne1NOSPAM@dsl.pipexSPAMTRAP.com>
wrote in message
news:k9epl153pmqce5oa54gkqcu30ujra1rf70@4ax.com
| Quote: | On Mon, 24 Oct 2005 21:49:26 +1300, "Geoff Wood"
geoff@nospam-paf.co.nz> wrote:
You have never seen the "screen" of an RF TV cable ?
|
Usually aluminum foil with maybe some braid (maybe aluminum
there, too) over it.
Nasty stuff to try to solder - crimped termination is the
order of the day.
| Quote: | Coax cables work on a totally different concept to
screened audio cable.
|
Well RF cables are designed to exploit the fact that the
frequencies are high enough for skin effect to be relevant
and even useful.
| Quote: | There's a centre core, there's a screen. Does its other
characteristics preclude it from being used as simple
screened cable for audio?
|
Probably the worst practical issue about coax that is
designed for RF is that the conductors are basically
copper-reduced and intended for use where the skin effect is
significant.
There may be silver plate on the outside of the conductor(s)
but the cores are likely to be steel or aluminum. This means
increased resistive losses.
Probably not going to be much of an issue with line-level
signals when line lengths are typical for a house.
Of course there are high-copper flavors of coax that work
swell right down to DC, and work pretty will for RF, too.
But, they may cost more or have less mechnical strength, or
both. |
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Richard Crowley
Guest
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| Posted:
Mon Oct 24, 2005 6:44 pm Post subject:
Re: Convert rca to coaxial - audio only |
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"Geoff Wood" wrote...
| Quote: | In/out impedences of most consumer audio gear is totally
unsuited for going more that a meter of two at the most
without hf drop-off.
|
We're talking about baseband audio here. Cable impedance
and transmission-line theory are completely irrelevant at
audio frequencies. Cable that is good for long distances at
300-500MHz can handle 20KHz without breaking a sweat.
Back in your grandparent's era, the telephone people
ran even wideband audio literally many miles/kilometers
using the matched-impedance power-transfer methodology
popular in that era. Today, it is trivial to design and cheap
to make audio equipment with output impedances on the
order of a few hundred ohms or even less. As you read
this, this kind of consumer line-level audio is distrubuted
throught many thousands of homes by this method with no
significant frequency/level losses.
| Quote: | You have never seen the "screen" of an RF TV cable ?
Coax cables work on a totally different concept to
screened audio cable.
|
I've been dealing with them for several decades. I am
quite familiar with most kinds of cable construction.
The "concept" is completely identical in every way.
Only the construction is different. |
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Stewart Pinkerton
Guest
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| Posted:
Mon Oct 24, 2005 7:47 pm Post subject:
Re: Convert rca to coaxial - audio only |
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On Mon, 24 Oct 2005 11:39:14 +0100, Laurence Payne
<lpayne1NOSPAM@dsl.pipexSPAMTRAP.com> wrote:
| Quote: | On Mon, 24 Oct 2005 21:49:26 +1300, "Geoff Wood"
geoff@nospam-paf.co.nz> wrote:
You have never seen the "screen" of an RF TV cable ? Coax cables work on a
totally different concept to screened audio cable.
There's a centre core, there's a screen. Does its other
characteristics preclude it from being used as simple screened cable
for audio?
|
No.
--
Stewart Pinkerton | Music is Art - Audio is Engineering |
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Stewart Pinkerton
Guest
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| Posted:
Mon Oct 24, 2005 7:47 pm Post subject:
Re: Convert rca to coaxial - audio only |
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On Mon, 24 Oct 2005 21:49:26 +1300, "Geoff Wood"
<geoff@nospam-paf.co.nz> wrote:
| Quote: | "Richard Crowley" <rcrowley@xpr7t.net> wrote in message
news:11loe9sctv7pl01@corp.supernews.com...
"Geoff Wood" wrote ...
michaeljc70 wrote ...
By coaxial, I mean the kind that runs through almost every home for TV
signal.
By RCA, I am talking about the input jacks on a stereo receiver.
The idea is totally flawed. Such outputs and cables are only designed
to go a short distance.
Disagree. In my experience, 100s (or even 1000s) of feet are not
impractical in many cases. The main hazard is the
possibility of ground loops between the equipment at each
end. Cable made for TV is good for 100s of MHz. 20KHz
of audio is of no concern whatsoever.
In/out impedences of most consumer audio gear is totally unsuited for going
more that a meter of two at the most without hf drop-off.
|
Depends on the cable, and on the output impedance of the source. A
decent opamp at the output will have a source impedance of less than
100 ohms, so with reasonable stuff like microphone cable, you can run
a ten-metre interconnect to your preamp or power amp with no problem
at all.
| Quote: | Disagree. They are, in essence, identical. "TV coax" (i.e.
cable made for RF frequencies) is merely designed for
lower loss at high frequencies, which is actually better
for audio frequencies.
You have never seen the "screen" of an RF TV cable ? Coax cables work on a
totally different concept to screened audio cable.
|
Only in so far as they generally have a defined characteristic
impedance. Otherwise, they're exactly the same as single-core screened
audio cable.
| Quote: | Forget the whole idea, or look into an audio-over-cat5 LAN cable
product.
Agree. No reasonably practical way to send two audio
signals (Left & Right stereo) over a single cable, whether
RF, or baseband audio coax.
|
That's certainly true, although you can of course buy multicore cables
which have individually screened cores.
--
Stewart Pinkerton | Music is Art - Audio is Engineering |
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