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XLR and Jacks


deranged-angel

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Hey all,

I was recently working at a venue that didnt have enough Jack leads for the CD player to go into the sound board so was told to use an XLR cable instead.  What are the pro's and con's of this, if any?

 

Cheers

Em

x

Generally speaking, an XLR is balanced, however a Jack is not. Also, on most sound boards the XLRs are intended for mic level input, and go thru a preamp (however, it is possible to put a line level signal into them) and the jacks are intended for line level signals e.g cd players, FX returns and the like. Unless the CD player has XLR out's, in which case you will need regular mic cables, you will requre a lead that is custom made, because you need to run an unbalanced signal to a balanced input.

 

TBH, in my opinion, it doesn't really matter. However, I wouldn't do it, if I had the choice. But it will work fine, providing you have the right lead (2x rca -> 2x XLR)

 

David

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hi,

also if you haven't got a desk that can individualy switch on/off phantom power for particular channels you might have an issue, if you have stuff that needs phantom that is otherwise you can just turn it off globaly... putting 48v into the output of a cd player might not be the best thing todo..

 

rgds

chris

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Generally speaking, an XLR is balanced, however a Jack is not.

 

Er, not usually true. On anything other than ultra-cheap "bottom feeder" boards, the jack inputs will be balanced TRS (tip/ring/sleeve) sockets.

 

Also, on most sound boards the XLRs are intended for mic level input, and go thru a preamp (however, it is possible to put a line level signal into them) and the jacks are intended for line level signals e.g cd players, FX returns and the like. Unless the CD player has XLR out's, in which case you will need regular mic cables, you will requre a lead that is custom made, because you need to run an unbalanced signal to a balanced input.

 

This is the nub of the problem. Some boards have a wide enough range on the input gain trims to allow you to use either input for either mic or line level, but the majority are expecting mic level on the XLR and Line level on the jack. In this case, since the house tech suggested it, I'd suspect that you can use either level into either input, but I'd do a bit of research (most mixer manuals are on the web) to make sure before I got caught out.

 

As for the balanced/unbalanced, unless the CD player is a professional unit, chances are you'd need a lead to adapt unbalanced into a balanced input anyhow, but these are common. If you need advice let me know and I can post the pin outs for wiring either route. (I'd do it now but it's bed time!)

 

Hope this helps.

 

Bob

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Hi all, thanks for all your replies.

 

The CD player did have an XLR socket on it and that went into the Mic socket on the back of the board. Oh yeah, I had 2 XLR's aswell-one for each side.

 

The problem I experienced was on the gain control. The board kept telling me that it was overpowering....(what's the term I'm looking for? There is a little light that pops on at the bottom right hand side of the fader that basically tells you it is too loud) well, anyway, this wouldn't go no matter how much I fiddled with the gain. The sound did alter but this light kept coming on. I wondered if this was because I was using XLR instead of Jacks.

 

It is also possible it was the board as it is seriously old and not very well looked after.

 

I just wondered. Not so very good at sound-I'm mainly a lighting person so beyond the normal set-up stuff, I am a bit lost <_< Please keep it simple-I'm not up on all the jargon that goes with sound!!

What would a pre-amp do to the sound? How does it change it?

 

Em

xx

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What mixer is it, deranged angel?

 

Your instincts are probably right...an XLR out on the back of a CD will be a line level, PROBABLY set for the professional standard of +4dBU=0 level. If the XLR input to the mixer is a mic-only one, it's very unlikely you'd have the range on the gain trim to knock things down enough. Sorry for the jargon. In simpler terms, "Line Level" is very loud compared to a microphone, and will almost certainly overload an input designed with quiet mics in mind.

 

One thing to look for: does the mixer have any kind of switched pad on the inputs? It would be a switch up near the top of the channel strip, labelled "Pad" or something like "-15 dB" or "-20 dB" or similar. If so, you should use this if you're not already--this is just a way to knock levels down significantly before you get to the variable controls.

 

Bob

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I think it's a yamaha desk. the show has actually finished now but was just curious for future reference. I'm not sure which model of Yamaha that it was but it's certainly pretty old.

 

There was the "pad" control and I fiddled about with this which helped. The gain wasn't actually labelled as gain but it did the same thing. When I brought up the music on the CD the gain was turned really high causing the speakers to seriously distort. Was an awful noise. Couldn't figure it out at first. With the minidisc though, I had these using jacks to the line inputs and even if I turned the gain up to match that of the CD with the XLR's it didnt distort like the XLR's did.

 

I think the lesson here is to get some jack-jack leads of my own and carry them to every venue I visit so I always have something that works and doesnt need fiddling with too much!!! heehee.

 

My next question is if I had a CD player with left and right channels and I had a desk capable of using 2 faders-one for left and one for right, would I need stereo or mono leads? I'm guessing mono because the sound is being split already by using 2 leads so each lead would carry it's respective sound to each fader -left and right???!!!! But if I only had one fader free on my desk would I simply have a mono jack into any input on the CD player (left or right) and have that going into my desk? Or would I have a stereo jack so that the cable splits the sound and still gives me stereo sound?

 

As you can tell, sound completely cunfuses me! I just need it explaining in very simple terms then I can get my teeny brain around it <_<

 

Thanks for all your help so far!

 

Em

xx

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Hello Em!

 

There is quite a simple answer to this one but is probably not quite the result you may expect. Let me explain:

 

My next question is if I had a CD player with left and right channels and I had a desk capable of using 2 faders-one for left and one for right, would I need stereo or mono leads? I'm guessing mono because the sound is being split already by using 2 leads so each lead would carry it's respective sound to each fader -left and right???!!!!

 

That is absolutely correct!

 

But if I only had one fader free on my desk would I simply have a mono jack into any input on the CD player (left or right) and have that going into my desk? Or would I have a stereo jack so that the cable splits the sound and still gives me stereo sound?

 

OK. You have one fader free on your desk. Using your example in your earlier post, you take two XLR cables (left and right) from your CD player and connect them to a Y-split. This is a cable fandangy with 2 female XLR's going into a male XLR and you then you plug it into your desk. This will sum together the left and right, unfortunately your signal won't be stereo anymore only mono.

 

Hope this makes sense, it's time for some shut-eye! <_<

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OK. You have one fader free on your desk. Using your example in your earlier post, you take two XLR cables (left and right) from your CD player and connect them to a Y-split. This is a cable fandangy with 2 female XLR's going into a male XLR and you then you plug it into your desk. This will sum together the left and right, unfortunately your signal won't be stereo anymore only mono.

 

 

 

 

Unfortunately its not that easy. Most sources don't like being run directly in parallel. The simple answer is to fit series resistors in the 2 female XLR's. If your CD player is a true 600 ohm output you way well get away without the resistors. I normally use 4k7 ohms in each leg ( pins 2 and 3).

 

Brian

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