Topic: How long can you run RCA cables without issue?

[achalsey]

I'm probably going to have to do a long run of RCA cables to get a board patch on Saturday and was wondering if using upwards of 50' would potentially introduce external noise or signal degradation.  I've used 19' pretty regularly with no problems.

[ScoobieKW]

50' is pushing it for unbalanced lines, 15 is the limit that most professional engineers will go.

a direct box like this would help you, it converts the unbalanced RCA to balanced XLR.
then 50' would be nothing.

http://www.sweetwater.com/store/detail/pcDI

If possible, see if you can get balanced outs from the board. If you need unbalanced ins, unbalance them at the input side.

[Patrick]

not long at all..

I made a bundle of cables (hdmi, ethernet, 25' rca audio) for my home theater system and I can hardly use the unbalanced line in that situation.

Granted it's hitting some enormous interference from the other components in the cabinet, but still!  25 feet is not that long.

[runonce]

50' is pushing it for unbalanced lines, 15 is the limit that most professional engineers will go.

a direct box like this would help you, it converts the unbalanced RCA to balanced XLR.
then 50' would be nothing.

http://www.sweetwater.com/store/detail/pcDI

If possible, see if you can get balanced outs from the board. If you need unbalanced ins, unbalance them at the input side.

Thats a pretty cool box...but a bit pricey.

On the cheap, you can do the same thing with this

http://www.sweetwater.com/store/detail/DI20/

or this...

http://www.sweetwater.com/store/detail/ZdirectDual/

just need some RCA to 1/4 adapters.

[achalsey]

Well, bummer.  Thanks for the heads up everyone.  That might make me rethink this plan.

That said, whats the actual issue here?  Is it external problems like EM interference from cell phones, or just noise in general introduced from long runs?

[ScoobieKW]

I'm probably going to have to do a long run of RCA cables to get a board patch on Saturday and was wondering if using upwards of 50' would potentially introduce external noise or signal degradation.  I've used 19' pretty regularly with no problems.

How about putting the recorder at the board? Send your mic/xlr runs the long distance to the recorder. They can handle the distance. (assuming you're going for a 4 track recording)

[achalsey]

I'm probably going to have to do a long run of RCA cables to get a board patch on Saturday and was wondering if using upwards of 50' would potentially introduce external noise or signal degradation.  I've used 19' pretty regularly with no problems.

How about putting the recorder at the board? Send your mic/xlr runs the long distance to the recorder. They can handle the distance. (assuming you're going for a 4 track recording)

Good point.  I am hoping to run mics through the snake back to the board, but am not going to be surprised if thats not an option.  Not an issue really, but I have the cable to run RCA, would need to borrow some XLRs.  Also, was hoping to share the patch so would need both of us in the same spot, which adds even more borrowing of cable if we're running XLR back to the board.  Again, not an issue, but just an extra step if we can't do RCA.

[SmokinJoe]

It's not a black and white, yes/no answer. I have a set of Ratshack 25' RCA cables I've used a hundred times, and I've never gotten interference that I can detect. It's largely a function of what the cables are running parallel to, and how good the shielding is.  If it's running along a shelf where 30 people put down their cell phones, across an air conditioner and through a server rack, you're screwed.  But if it's clipped to a ceiling with nothing else around, you are probably good.

[Gutbucket]

Longest I did was a fest were I burried a line from my FOB stand spot to the SBD patch box.  Used one of those 25' stereo RCAs and needed to extended it another 10' to reach.   I was warry, but it worked fine.

[scout72]

Related question to RCA cable runs- is there any difference / benefit to types of unbalanced runs? Is it any better to run shielded 1/4" TRS versus shielded RCA? Is the type of shielding inherently different in any way or can you make any cable equally shielded?

Thanks!

[ScoobieKW]

Related question to RCA cable runs- is there any difference / benefit to types of unbalanced runs? Is it any better to run shielded 1/4" TRS versus shielded RCA? Is the type of shielding inherently different in any way or can you make any cable equally shielded?

Thanks!

Bringing this back to life.

Let's break this down into connectors and cable.

TRS (1/4" or 1/8") connectors support 3 conductors for either stereo unbalanced (headphones) or balanced mono.
TS connectors support two conductors for unbalanced audio
RCA supports unbalanced audio.

Cable. Shielding types vary from cable to cable. High quality cables for our applications are usually braided. Foil wrapped shield also works well, but doesn't hold up with uncoiling/recoiling.

So, to answer the original question. (Finally)
A 1/4" TRS cable will be superior to a RCA cable if the devices support balanced audio.
B. a 1/4" TS cable will be equivalent to an RCA cable if built with the same cable (except that the 1/4" connector is more robust)
C. In the real world, RCA cables are often built with lower quality materials than cables terminated in 1/4"