PC to PA over 60m run

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abie145

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I need to connect a USB/audio PC output to a PA system mic input over 60m away. The PA amp is an ITC Ti-240 with only 1/4 inputs.
How do I do this? I understand there are issues with 1/8-1/4 cables being unbalanced and interference.
 
I would assume you would want to adapt to a balanced signal somehow and run through a snake with balanced cables. 150' is typically no problem with balanced cables.

Just a quick search found THIS.

I have no 'real world' experience with such an issue so I am just guessing here.

If you are trying to send a USB signal that far, I think you are out of luck.
 
if you have a snake, you can use one of the XLR channels with a DI box on the end to convert, or use XLR transformers. on our concert rigs our snakes were 500 footers, we ran our signals from the board to the stage with no issues. :D
 
Hay guys, the PA does not have balanced inputs at all, so balancing it at the source won't help him.

You know what, I would try it with unbalanced cables and see if there is a problem first up, if there is you will have to convert to balanced then to un-balanced at each end. What I would do, get hold of a cheep mixer with balanced inputs like a little Behringer thing like this and plug the little mixer into one of the unbalanced line ins on the existing PA, then I would used the suggestions above to balance the signal at the computer end, or is the USB sound card already balanced?

Alan.
 
That's correct about the PA being unbalanced. I would just try but with this long piping in flexible hose over such a distance I am afraid I will only get one chance at running the cable so I want to get it right in the first place.
Thanks for all the suggestions.
 
the problem isn't really balanced vs unbalanced, but impedance - high impedance down a long length of cable means a loss of HF, so the result will be dull. You can try to boost it at the send end, I suppose - but if it's a one shot, and you need to bury cable - then bury mic cable, and then try all the ways mentioned. Alternatively, you can always buy a cat 5 system - these kinds of thing PRO SIGNAL - PSG08180 - CAT 5 BALUN, STEREO AUDIO | CPC UK
 
It looks like I should run mic cable so if I need to do shtick to get it balanced I will have the shielding and third wire in place already, then I can play with it from there.
I have no clue if the USB output is balanced, some Chinese USB device there from before my times. in the current setup the PA was in the same rack as the server, but I need to add another location feeding another PA too.
 
If this is a 1 shot install run at least 2 x balanced (2 core & shield) mic cable, then you have options later, maybe run a cat cable as well.

Alan
 
witzendoz said:
If this is a 1 shot install run at least 2 x balanced (2 core & shield) mic cable, then you have options later, maybe run a cat cable as well.

Alan
Click to expand...


Right.
You don't want to pull cabling twice with such a difficult situation, so run extra and run for possible future upgrade.
I would use all balanced audio cabling, which you can easily adapt for unbalanced use...but if you run unbalanced cabling, and later things change to balanced, you would have to run more cabling.
 
PRO SIGNAL - PSG08200 - STEREO AUDIO OVER CAT5 | CPC UK

I have two of these and the sister boxes that also send CVBS down CAT5e they are pretty good for the money.

Yes, the OPZ of the send device needs to be low but it would be a pretty crap AI these days that was not around 100 Ohms or less. If it IS that crap, use the headphone output.

The big advantage is, CAT cable is very cheap, even free if you talk to a network installer nicely.

Dave.
 
miroslav said:
Right.
You don't want to pull cabling twice with such a difficult situation, so run extra and run for possible future upgrade.
I would use all balanced audio cabling, which you can easily adapt for unbalanced use...but if you run unbalanced cabling, and later things change to balanced, you would have to run more cabling.
Click to expand...

Also if you are running this wiring in tubing, buy proper electrical conduit, oversized, so that you can pull extra cables and cores through later if you need anything else or technology changes what you need. This is called future proofing.

Alan.
 
On the computer end, you can't use a USB output, unless you're sending that to a DA converter (like an audio interface) first. USB is not audio.
 
ecc83 said:
PRO SIGNAL - PSG08200 - STEREO AUDIO OVER CAT5 | CPC UK

I have two of these and the sister boxes that also send CVBS down CAT5e they are pretty good for the money.

Yes, the OPZ of the send device needs to be low but it would be a pretty crap AI these days that was not around 100 Ohms or less. If it IS that crap, use the headphone output.

The big advantage is, CAT cable is very cheap, even free if you talk to a network installer nicely.

Dave.
Click to expand...

I am a network installer and no one ever threw me free quality cable, maybe I should find friends to talk to.
In any event I am going to run two Cat6 cables full copper (one I need for the network), and two balanced lines.
I am going to test from there and see what more gadgets you people have suggested will be necessary.

I spoke to a local audio guy who has tons of experience in performances, equipment and such and he said using balanced cable even if you aren't using the shielding in its real capacity still serves enough for interference, this is after all for an announcement and musical bell system
I will post back with results.

You people have been extremely helpful.
 
abie145 said:
I am a network installer and no one ever threw me free quality cable, maybe I should find friends to talk to.
In any event I am going to run two Cat6 cables full copper (one I need for the network), and two balanced lines.
I am going to test from there and see what more gadgets you people have suggested will be necessary.

I spoke to a local audio guy who has tons of experience in performances, equipment and such and he said using balanced cable even if you aren't using the shielding in its real capacity still serves enough for interference, this is after all for an announcement and musical bell system
I will post back with results.

You people have been extremely helpful.
Click to expand...

I was a test bed and project builder for a network company for 10 years and they skipped at least a 100kg of cable a year. My whole house is wired, several times over, all for free!

And no, if the source Z is low enough and the balance good shielding is often not needed.

Dave.
 
ecc83 said:
I was a test bed and project builder for a network company for 10 years and they skipped at least a 100kg of cable a year. My whole house is wired, several times over, all for free!

And no, if the source Z is low enough and the balance good shielding is often not needed.

Dave.
Click to expand...

I too spent many years running cable and installing networks, companies don't just "skip" cable for nothing, they charge the customer for it in some fashion. :D
 
Atkron205 said:
I too spent many years running cable and installing networks, companies don't just "skip" cable for nothing, they charge the customer for it in some fashion. :D
Click to expand...

This was a pretty stupid company and I eventually left after telling the CEO he was *^%%!ing mad.

Dave.
 
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