RG 58 or RG 8 cable for audio signals

[josko]

I need about a 50' cable run between audio components and need to work with RCA plugs. How would either RG-6 or RG 58 cable with RCA terminations work for this? I realize XLR (balanced) connectors are preferable, but one end doesn't have XLR's.
So, am I better with a 50' run of RG-6, RG-58 or a 50' length of some other cable?
Also, I'm assuming that a 50' cable will be quieter than a wireless link. I see I can get a variety of wireless links with RCA inputs/outputs, but kind of think that a cable will perform better here. Am I right?
Thanks in advance.

 

[markw]

I know the RG-58 is 50 ohms. RG-6 is 75 ohms.

I would recommend either RG-59 or RG-6, which are both 75 ohms. Although 50 ohm cables will work for audio, 75 is useful for anything, including video applications, antennas and cable TV as well.

 

[josko]

What exactly does it mean for a cable to be a '50 ohm', or '75 ohm'. When I measure DC resistance between the two parts of an open-ended coax, I get basically infinite impedance for RG 58 or RG 6. Does that mean that at higher audio frequencies, the cable impedance drops to 75 or 50 ohms?

 

[markw]

Although "impeadence" is stated in ohms, like simple DC resistance, it is not a simple resistance reading. The longer the run, the more it becomes important.

It's a calculated number that varies with frequency. The math and theory is beyond my abilities to explain, but I'm sure others (or perhaps google) can provide a more comprehensive explanation.

 

[Rickster71]

If I may add to what Mark mentioned.
A basic rule of thumb is to use RG6 for any high Frequencies,(CATV, Sat) and use RG59 for lower frequencies. (audio patch cables, etc)

 

[josko]

Thanks guys,

at what frequency would I start to see measurable impedance differences between, say, RG-58 and RG-59. Why is one better for audio interconnects than the other?

 

[markw]

I guess that depends on how you measure a calculated number.

As I said before, it's a calculated number that varies with frequency. The math and theory is beyond my abilities to explain, but I'm sure others (or perhaps google) can provide a more comprehensive explanation.

You might want to try googling this for yourself instead of continuing to ask the same questions. I'm sure all your questions will be answered.

Here's a start : http://www.epanorama.net/documents/wiring/cable_impedance.html

Hope that helps.

But, as I also said earlier, either cable will work for audio. The frequencies involved don't really care about the impedance.

 

[Xing]

The most important thing is to make sure that if you do go with RG6,
you will not buy one of the Steel Core types & use it for audio.

if a cable is quite stiff , be suspicious & make sure the core is pure copper,
or Silver plated copper , but NOT steel core plated copper.