Coax Versus Analog Cable?

[ahblaza]

Hey guys,
I posted this query in the beginners section because I feel like one asking this question. Every cable in my setup is BJCs. All cables are specifically BJC LC-1 analog cable with the exception of HDMI, video and digital cable of course, and those are also BJC. I needed recently a few lenghts of analog interconnects and decided on a reco to go with the Belden (from BJC) 1694A coax which is the video Brilliance line. These will be used strickly in an analog application, interconnects and sub cable. Is there any advantage going with the coax over my favorite analog only cable the LC-1. I've read that many folks were using a digital coax in an anlaog application, so what do you think using the coax for analog? I don't know how critical this is but I thought I would throw this out there to get some feedback, thus the beginners forum. Should I just stick with the LC-1 or use these 1694As as analog cables? Thanks for your time (probably wasted).
Cheers Jeff

 

[Steve81]

Don't know if you've seen it, but FWIW, the 1694A is also listed on the "stereo cables" section at BJC along with the LC1, with some pros and cons listed.
Stereo Cables at Blue Jeans Cable

Belden 1694A:

Belden 1694A is also an excellent choice for analog audio; its foil/braid shield, though slightly less effective at excluding low-frequency EMI than 1505F's double braid shield, provides better RFI rejection, so 1694A may provide better shielding performance if you are beset with RFI issues. 1694A is an RG-6 type solid-core cable, and so is somewhat thicker and stiffer than 1505F. View Belden's technical specs for 1694A.

 

[markw]

I'm not trying to be a smart-a$$, but, from the description at the BJC website, I do believe both cables in question are both "coax" cables.

By definition, a coax cable consissts of one conductor in the center surrounded by an insulator. This, in turn, is surrounded by a metallic shield, either foil or braid (or both) surrounded by another insulator. That insulator between the central connector and the shield acts as a dielectric, which has electrical significance in the overall characteristics of the cable in question. More detail is beyond my pay grade but that should suffice for now.

Depending on the inner insulator (dielectric) and their construction, these cables can have differing capacitance, where lower can be preferred in many cases, which seems to be the LC-1's major selling point. For short lengths it's not too much of a difference but as te runs get longer, the increased capacitance can have a cumulative effect. But, that Belden is no slouch either and has been pretty much a standard for audio interconnects.

Now, some a rules of thumbs:

Digital and video cables are specced to be 75 ohms.

Analog interconnects can be anywhere between 50 and 110 ohms, or at least they used to be. Nowadsys, due to economies of scale for manufactureing, many are 75 ohms as well.

Any video or digital cable will be fine as an analog interconnect.

My experience has shown me that any interconnect I grab works fine for a digital interconnect.

 

[slipperybidness]

I'm not trying to be a smart-a$$, but, from the description at the BJC website, I do believe both cables in question are both "coax" cables.

By definition, a coax cable consissts of one conductor in the center surrounded by an insulator. This, in turn, is surrounded by a metallic shield, either foil or braid (or both) surrounded by another insulator. That insulator between the central connector and the shield acts as a dielectric, which has electrical significance in the overall characteristics of the cable in question. More detail is beyond my pay grade but that should suffice for now.

Depending on the inner insulator (dielectric) and their construction, these cables can have differing capacitance, where lower can be preferred in many cases, which seems to be the LC-1's major selling point. For short lengths it's not too much of a difference but as te runs get longer, the increased capacitance can have a cumulative effect. But, that Belden is no slouch either and has been pretty much a standard for audio interconnects.

Now, some a rules of thumbs:

Digital and video cables are specced to be 75 ohms.

Analog interconnects can be anywhere between 50 and 110 ohms, or at least they used to be. Nowadsys, due to economies of scale for manufactureing, many are 75 ohms as well.

Any video or digital cable will be fine as an analog interconnect.

My experience has shown me that any interconnect I grab works fine for a digital interconnect.

I'm pretty sure that you are correct in that both styles are actually coax, by definition. I can't remember for sure, but I think the LC-1 is more flexible than the 1694 and I prefer the LC-1 simply for that reason.

 

[Speedskater]

The BlueJeans LC-1 and the Belden 1694A are very similar cables. With the exception that the 1694A has better high radio frequency shielding and the LC-1 has better low frequency shielding. The capacitance of both cables is very low. I doubt that you could find an analog audio situation that one would be better at than the other.

That old 75 Ohm business is the radio frequency characteristic impedance and has nothing to do with real world analog audio.

 

[TLS Guy]

Hey guys,
I posted this query in the beginners section because I feel like one asking this question. Every cable in my setup is BJCs. All cables are specifically BJC LC-1 analog cable with the exception of HDMI, video and digital cable of course, and those are also BJC. I needed recently a few lenghts of analog interconnects and decided on a reco to go with the Belden (from BJC) 1694A coax which is the video Brilliance line. These will be used strickly in an analog application, interconnects and sub cable. Is there any advantage going with the coax over my favorite analog only cable the LC-1. I've read that many folks were using a digital coax in an anlaog application, so what do you think using the coax for analog? I don't know how critical this is but I thought I would throw this out there to get some feedback, thus the beginners forum. Should I just stick with the LC-1 or use these 1694As as analog cables? Thanks for your time (probably wasted).
Cheers Jeff

Coax cable for digital transmission has an impedance of 75 ohm per foot. (this is nothing to do with the resistance of the cable). Analog coax cable has an impedance of 50 ohm per foot. Either cable will work equally well for analog signals.

However to minimize termination reflections you should use the 75 ohm cable for digital use, to minimized termination reflections and data cancellation. However you can usually get away with using analog cable for digital transmission as error correction is so robust. However I advise against it.

 

[Speedskater]

While digital audio co-ax cables have a "radio frequency characteristic impedance" of 75 Ohms, many analog radio and TV co-ax cables are also 75 Ohms.
At analog audio frequencies, a co-ax cable has no simple "radio frequency characteristic impedance".

 

[ahblaza]

Thanks guys for all the replies, I did keep the 1694 and it is very similar to LC-1 except it is thinner and less flexible, my primary concern is capacitance per foot but I'm using such short lengths that it does not come into play. The 1694 rejects RFI better than the LC-1 and has higher capacitance per foot also, the LC-1 is rated 12.2 PF/FT and the 1694 is 16.2 PF/FT, so I am happy with my choice and Gene used all 1694 as interconnects and balanced cable for his review of the Titus speaker. Thanks again to all.
Cheers Jeff