• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

RG179 for line level audio and/or SPDIF

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,226
Likes
17,806
Location
Netherlands
I’m about to lay some cables. I really don’t need a discussion about the audiophile qualities of cables :facepalm:, just want to know about the technical usefulness.

So, I’m reshuffling some stuff so I can add two sub’s and possible some side and rear speakers for surround. For this I’ll be adding a few additional wall outlets next to already existing ones. One at the source where av receiver and DSP are located, and the two at different locations in the room. All those have little room to feed cables through. There is really no way to change this without a major renovation. They end up in the cellar where is can distribute them as is needed. Little room means tiny cables.

Next to this I’d like them to work for both line level audio as well as SPDIF, so I might be ready for future changes. The idea is to use 75 ohm coax. Smallest diameter cables I could find is RG179. Longest cables length needed is probably about 8 to 10 meters.

This way I can still get like 3 or 4 cables through the tubes, which should be enough for starters.

So, what do you guys think? Is this a good solution? Is there a better one? Any tips are welcome :cool:
 

KSTR

Major Contributor
Joined
Sep 6, 2018
Messages
2,690
Likes
6,013
Location
Berlin, Germany
For SPDIF no problem, but 10m of unbalanced line level might raise hum/buzz issues. I'd certainly test that before a final install.
Btw, there are micro-coaxial cables available with diameters as low as 0.2mm and even lower ;-)
Probably not ideal for the purpose (and they ususally are 50Ohms).
 
OP
voodooless

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,226
Likes
17,806
Location
Netherlands
For SPDIF no problem, but 10m of unbalanced line level might raise hum/buzz issues. I'd certainly test that before a final install.
Btw, there are micro-coaxial cables available with diameters as low as 0.2mm and even lower ;-)
Probably not ideal for the purpose (and they ususally are 50Ohms).

Yeah, I figured as much, but no other unbalanced cable will be much better I guess? What about CAT6e or CAT7? They are 100 Ohm, so close probably close enough to the 110 Ohm needed for AES, and It could do (pseudo)balanced line-level audio as well. It's also relatively cheap, and since it bundles multiple strands, is quite efficient size-wise. CAT7 even offers double shielding. Another thing of interest is that I could use a UTC wall socket, and then just make an adapter cable to whatever standards I need. I could even run speaker level though there when bundling a few strands.
 

KSTR

Major Contributor
Joined
Sep 6, 2018
Messages
2,690
Likes
6,013
Location
Berlin, Germany
@voodooless , yes, network cables are also a good alternative, and actually are used in studios for analog balanced signals as well as AES3. I would't probably mix analog and digital within the same cable but actually that might be OK, depends on the RF-immunity of the analog circuits. Theoretically, the different twist rates of the TP's should result in minimal coupling between pairs but I would not simply rely on that.
 
OP
voodooless

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,226
Likes
17,806
Location
Netherlands
Theoretically, the different twist rates of the TP's should result in minimal coupling between pairs but I would not simply rely on that.

CAT7 would then mostly solve that since they have every pair shielded as well?

Well, network cable it is! It will also save me quite a lot of money this way, and I don't have to doctor some Frankensteinian wall sockets or resort to ill-fitting Chinese contraptions :facepalm:
 

raindance

Major Contributor
Joined
Sep 25, 2019
Messages
1,037
Likes
968
If you use network cables there's always some dedicated extenders you could drive/ receive signal with. Look at Kramer or Extron or similar and see which cable they're recommending. Their boxes will balance/unbalance the signal for you.
 
Top Bottom