Cat 5

[soundiesam]

Hey all need some info regarding cat 5 multicore. I was told it is possible to do with anologue equipment anybody enlighten me how to do it?

sam

ut

I didnt explain this very well a church told me they were getting a cat 5 multicore for there 8 channel desk but ive never heard of cat 5 being used in small installs like this but if its possible but I would love to know how to do it as im just about to install a new multicore at my church and it might be a lot cheaper for me

[Shez]

Cat5 can indeed be used for balanced audio. Each cable is four twisted pairs so will carry four channels of audio. However, if you need to be able to send phantom power, the wiring scheme becomes a little more complex as you need three cores rather than two.

 

I think the cost of installation multicores is likely to be rather less than multis that will be moved around every night. Make sure you're comparing like with like here.

[paulears]

Cat 5 is fine for digital links, and to be fair, as twisted pairs, ok for line level balanced audio for some circumstances, but it does have a number of problems - screening and ground connection is absent, so it's not that useful for interconnecting equipment that needs 3 conductors - as in XLR outputs. It's dirt cheap of course, but if they want to run low level stuff through cat 5, it isn't much use without something to get the level up at the stage end - and this bit costs money, which in an analogue system would have been better spent on decent screened multicore.

[soundiesam]

cheers Paul this is what I thought I did find these why looking on the internet at the idea which looks quite interesting!

cat 5 connectors

anybody used them or knows someone who has used them?

sam

[TomLyall]

cheers Paul this is what I thought I did find these why looking on the internet at the idea which looks quite interesting!

cat 5 connectors

anybody used them or knows someone who has used them?

sam

 

It's just a "neat" way of doing what your suggesting. That box is completely passive, you might as well just use choc-block or solder the cat5 directly into the XLR.

[p.k.roberts]

Probably everything you ever wanted to know about running audio (and just about everything else) over cat 5 and various other types of cable can be found here;

http://www.canford.co.uk/news/2007/BeldenS...arDownload.aspx

Set aside a considerable amount of time to watch the whole presentation, but there is some great info here.

[6th Order]

Pretty sure the only way to run 8 channels over cat 5 is to use a digital muticore i.e. pre-amp --> A/D converter --> cat 5 --> D/A converter --> desk.

 

Most of the main systems are quite big, but there are several 8 channel units you could use.

 

Back to the OP, how many sends/returns do you need?

[Shez]

I saw the presentations that Mr Roberts linked to a couple of months back; they're very good - it's amazing what you can actually send down CAT5.

If your equipment & cables work properly, you don't need screens on the cables - the whole point of a balanced system is common mode rejection of interference.The CMRR of some receiving equipment isn't nearly as good as it should be right across the audio bandwidth, which is the only reason screened cables are necessary.

As I said earlier, the biggest problem will be if you need phantom as that requires the third conductor. For your application, I suspect that this will be the case (condenser mics).

Drummerboi - the OP was talking about a CAT5 multi, not a single cable. Eight (analogue) channels would need two "cores" of a such a multi.

[6th Order]

I'm looking forward to looking forward to watching those presentations. They sound very interesting.

 

Drummerboi - the OP was talking about a CAT5 multi, not a single cable. Eight (analogue) channels would need two "cores" of a such a multi.

 

Having re-read the OP I agree.

[paulears]

The thing is...... yes you can do it, subject to the issues dealt with above, but why? Why pioneer your way through audio down cat 5, solve the problems found on the way, when you could just buy multicore and bung on a few XLRs, with guaranteed results. Using extra cores to provide the required ground for the phantom, and ensuring no crosstalk from line level going one way to mic level the other seems a little hopeful. It may well work, and if you have time and energy to try it - great. Me, I leave pioneering to others.

[bruce]

I've done this several times, in high-profile situations. 100% success so far. In fact, I've got a system going "live" in a couple of days(*) which is the main desk>transmitter link for a radio station.

 

In each of these situations, audio-over-CAT5 has worked, and has worked well, and was the most cost-effective option. But it was never the first choice from a technical perspective. In each case, the driver for using CAT5 rather than conventional cabling was that the cat5 was already installed in the building.

 

(*) That assumes my 100% record continues. If the link turns out to be bad - and it does pass a little too close for comfort to an Orange transmitter and to some lift motors - then I guess we'll spend next weekend installing screened cables up a tower block...

[peternewman]

There is a product called BrikWorm, which is a small digital multicore, running over Cat 5. I've no personal experience of it, I merely know it exists.

[Shez]

Just looking at a bit of CAT5 now; I suspect CMRR performance may actually be better with CAT5 than with conventional audio cables. The cores are closer together and twisted more tightly, both of which will help. If I come across a suitably long off-cut, I'll see if I can compare it with an equivalent "audio" cable. At the end of the day, it's just a twisted pair; nothing pioneering.

[Pete McCrea]

The Aviom system is another product, but works using A-D and D-A's. They get 16channels down each pair, so 64 lines down one 4pair CAT5

[bruce]

In fact, I've got a system going "live" in a couple of days(*) which is the main desk>transmitter link for a radio station.

.

.

(*) That assumes my 100% record continues. If the link turns out to be bad - and it does pass a little too close for comfort to an Orange transmitter and to some lift motors - then I guess we'll spend next weekend installing screened cables up a tower block...

 

Well, it's working remarkably well, so no need for a plan-B.

 

If you're in the Glasgow area, try 106.6 sometime over the next fortnight. (but not until Monday, cos that's when the OFCOM license starts....)