**HELP** XLR wiring advice needed

[marksav62]

Hi everyone, I an a newbie and this is my first post.

 

I have recently purchased a Crown XLS402D amplifier with twin female XLR inputs on the back panel.

 

I am using this amplifier with a standard disco console having twin Numark CD players and a Numark mixer.

 

The console has the 2 master outputs (RCA) from the mixer connected to a XLR male connector.

 

At the time I purchased the amplifier I ordered a Y cable with single XLR female to twin XLR male.

 

However when I connect this cable between the amp and console, I get sound which sounds completely out of phase.

 

The only way to get decent sound is to disconnect one channel from the back of the mixer.

 

However of course, this way I only get mono sound.

 

Can anyone help me establish what needs to be corrected?

 

Many thanks

[adamharman]

Sounds like your RCA to XLR lead has some funny wiring.... You need to either buy or make a pair of RCA to XLR cables.

 

This from CPC should fix it http://cpc.farnell.com/pro-signal/psg01377...no-p/dp/AV14545

 

Or if you can use a soldering iron, connect the centre pin of the RCA to pin 2 on the XLR, and the screen to pins 1 and 3 of the XLR

[MarkPAman]

The console has the 2 master outputs (RCA) from the mixer connected to a XLR male connector.

I take it this is something that's been added by somebody and is not part of the mixer?

 

I'm guessing that left is wired to pin 2 & right to pin 3 (or the other way) with 1 as a common ground. Your Y lead is balanced, so will feed both left & right into each side of the amp with strange results.

 

You could re-wire your Y lead to do this, but I think I'd start again here - make or buy two phono - XLR cables - Pin 2 hot, 1 & 3 cold.

 

E2A Too Slow!!

[Yorkie]

This sounds like it's because you are feeding Left & Right from the mixer into + & - on each of the Amp channels. What you need to do is feed Left into + on the Left amp channel and Right into + on the Right amp channel.

 

A pair of these will sort you out: http://www.studiospares.com/Leads-XLR/XLRm...ack/invt/579190

 

If you want to make your own, connect as follows:

XLR RCA

1 Screen

2 Centre

3 Screen

 

 

(Sorry, I think this has come up before; a more considered search than the one I did should help.

 

Edit: Much too slow!!

[mervaka]

how is the XLR/RCA connector wired? sounds like you're running hot to one channel, cold to the other!

 

preferably, you need to balance your signal using something like this, but alternatively you could make a pair of new leads up, with an XLR at one end, and an RCA connector at the other. inside the XLR plug you should short pins 1 and 3, grounding the 'cold' signal.

 

RTFM on page 9 for more details on wiring your unbalanced lead.

 

EDIT: got 3 replies in the time it took to write mine while eating my lunch

[marksav62]

Hi Folks,

Thanks for the replies, it's very much appreciated.

 

The problem I have is that the mixer, CD's etc. and built into a flight case, so the RCA sockets on the mixer are not readily accessible, hence the RCA's are connected to the XLR connector mounted on the flight case by phono cables.

 

Am I correct in thinking I should do the following.

 

Make sure that the exisitng XLR on the case is wired as follows:

 

Pin 1 - Both L and R screens from phono cables

 

Pin 2 - Both L and R positives from phono cables

 

Pin 3 - Both L and R negatives from phono cables

 

OR

 

I could forget about the screens and solder a link between pins 1 and 3?

 

Assuming this is ok, then my Y cable should function OK????

 

Many thanks

[mervaka]

no, you need to treat L and R separately. hot from phono should go to pin 2 of the XLR. screen from phono should go to pins 1 and 3 of the XLR. if you want, you can make these leads short so you can leave them connected to the desk and plugged in when used, and use a pair of standard XLR cables to run to the amp

[MarkPAman]

You XLR in the console will have both Left & Right as an unbalanced signal. It's not that unusual in DJ circles and is often used for turntable - mixer connections, but not something I've ever seen as an "off the shelf" cable.

 

Let's assume it's wired:

 

Pin 1 - Both screens from phone cable

Pin 2 - Left positive

Pin 3 - Right positive

 

 

You need to change your Y lead so that Pin One is the screen on all connectors (it will already be like this, I hope)

 

On the connector for the left amp pin two comes from pin two of the female,

 

On the connector for right amp pin two comes from pin three of the female

 

Both amp input connectors have pin 3 shorted to pin 1

 

You'll have an unused conductor in each part - make sure it's not shorting on anything.

 

;)

[marksav62]

You XLR in the console will have both Left & Right as an unbalanced signal. It's not that unusual in DJ circles and is often used for turntable - mixer connections, but not something I've ever seen as an "off the shelf" cable.

 

Let's assume it's wired:

 

Pin 1 - Both screens from phone cable

Pin 2 - Left positive

Pin 3 - Right positive

 

 

You need to change your Y lead so that Pin One is the screen on all connectors (it will already be like this, I hope)

 

On the connector for the left amp pin two comes from pin two of the female,

 

On the connector for right amp pin two comes from pin three of the female

 

Both amp input connectors have pin 3 shorted to pin 1

 

You'll have an unused conductor in each part - make sure it's not shorting on anything.

 

;)

 

Hi Mark,

 

Thanks for the explanation, I am pretty sure the way you describe the single XLR will be undoubtedly what we have, just to be clear, the unused conductors are the -ve (or cold).

 

Gonna give this a try, if I have any problems, I'll fit another XLR to the flight case and run as 2 seperate cables.

 

Cheers

 

:up:

[smalljoshua]

Make sure that the exisitng XLR on the case is wired as follows:

 

Pin 1 - Both L and R screens from phono cables

 

Pin 2 - Both L and R positives from phono cables

 

Pin 3 - Both L and R negatives from phono cables

Can you put a 2nd XLR on the Case?

 

Wire the 1st XLR

 

Pin 1 - Right Negative/Screen

 

Pin 2 - Right Positive

 

Pin 3 - Right Negative/Screen

 

Wire the 2nd XLR

 

Pin 1 - Left Negative

 

Pin 2 - Left Positive

 

Pin 3 - Left Negative/Screen

 

Josh

 

edit: crosspost

[marksav62]

OK thanks everyone for your replies.

 

I followed MarkPAman's advice to rewire the Y cable, the XLR on the flight case had indeed been wired the way he described.

 

All is completed and now working absolutely perfectly.

 

Can't thank you enough for your willingness to help me out.

 

Mark.

[Rob_Beech]

If you have the budget, I'd consider buy 2 cheap passive DI boxes and plugging the phono's into that (maybe via a jack adaptor) then connecting the outputs to 2 (drill a new one) outputs on the back of the rack. That way you HAVE a balanced signal and if ever you line out to another larger system you have hired, you are not worried about cable length and picking up noise from unbalanced signals. Shouldn't cost you more than £20 and the job is done properly.

[Stuart91]

If you have the budget, I'd consider buy 2 cheap passive DI boxes and plugging the phono's into that (maybe via a jack adaptor) then connecting the outputs to 2 (drill a new one) outputs on the back of the rack. That way you HAVE a balanced signal and if ever you line out to another larger system you have hired, you are not worried about cable length and picking up noise from unbalanced signals. Shouldn't cost you more than £20 and the job is done properly.

 

Won't this approach cause problems if he is trying to drive the amp input directly from the DJ desk output?

 

I agree it's an excellent solution if he's being connected to the mixing desk of a larger PA system - I wish more of the DJs I met used something similar!

[Rob_Beech]

Not normally a major issue, the input impedance of an amp tends to be lower. Though I understand where you're coming from. Potentially 4 outputs would be better but then it gets a bit "silly".