XLR female to stereo jack

[IA76]

Hi

 

I've been practicing with making up cables and I've got the hang of soldering but I've made a mistake on a cable.

 

What I want to do is use one of the main out from my mixer to feed sound to my laptop.

 

I have made a mono jack to mono jack cable which goes from the main out L on my Behringer 1002FX mixer to the input of a DIB-100 DI box.

 

The output from the DI Box is an XLR to I need to make a female XLR to 3.5mm stereo jack cable and it's this cable which I think I have messed up.

 

It's wired like this:-

 

3.5mm STEREO JACK

RED to left

BLUE to right

GROUND to ground

 

XLR FEMALE

RED & BLUE to pin 2

GROUND to pin 1 & 3

 

What have I done wrong as I'm not getting any sound to my laptop?

 

Thanks

[Alec]

Had to read this a few times to work out what (I think) is going wrong.

 

Presumably, the laptop input is expecting a line-level input? But you're using the DI box, which will be converting to a mic level input.

 

What's wrong with connecting directly from the mixer to the laptop, with a 6.35mm to 3.5mm jack to jack cable?

 

Also, just to check it's not a typo - you are using a passive DIB-100, and not Behringer's active DI-100, right? As an active DI won't be receiving any phantom power in the configuration you describe, you'd need to power it by battery or a separate PSU.

[IA76]

Hi Alec

 

Yes it's a passive DIB-100.

 

The reason I was using a DI box is because the mono jack to mono jack cable from the mixer is about 30m long so I was using the DI box to make it a balanced signal to reduce the risk of picking up interference.

[IRW]

Hi Alec

 

Yes it's a passive DIB-100.

 

The reason I was using a DI box is because the mono jack to mono jack cable from the mixer is about 30m long so I was using the DI box to make it a balanced signal to reduce the risk of picking up interference.

 

Is your laptop expecting a balanced signal? Or are you going into a stereo line in port?

[IA76]

I'm going in to the stereo line in port on the laptop.

[paulears]

You've joined the red and blue on the laptop jack - this is correct, putting the mono signal onto both input channels. The XLR wiring is also correct for unbalanced operation - 1 and 3 joined and signal on 2. So the cabling is ok (or at least, appears to be - assuming it's not shorted somewhere). First thing then is to use a meter on the cable and verify that your connections are exactly what you say. It's not uncommon for cheap 3.5mm jacks to melt from too much heat inside the jack shaft, so check to make sure the tip and ring are connected and that there isn't a short to the sleeve. Check continuity from jack to XLR pins. Assuming the cable tests out ok, the I would plug the cable into the laptop, and then get a paperclip and unbend it. Paperclips are amazingly useful! With the laptop ready to record - so with sound on and a meter visible or whatever - stick the paperclip into the hole marked 2 on the XLR. If you get crackles and buzzes and hums - the cable is fine. Assuming this works, then nothing appears to be coming out of the DI XLR. So plug the DI in and then if you have one, stick in a 1/4" jack without it's cover, or lacking that, a known good guitar type cable - and do the touch test on the other end. Work from the laptop towards the source a stage at a time and at some point it will go wrong.

 

The jack in on a laptop can be at mic level or line level. My guess is yours is simply set to line, as mentioned and there's simply not enough ooomph going in!

[revbobuk]

OK - you're using the DI box to balance the output from the mixer. That's OK - although line level signals, even over 30m, won't usually be afftected by interference. However, by grounding pin 3 on the XLR you unbalance the output of the DI box anyway. There's no way to feed an unbalanced input from an unbalanced output with a balanced line inbetween that doesn't use 2 transformers or other balancing devices, one at each end of the long cable.

 

I'd suggest you don't bother with the DI. Just try an adapter from the long lead to 3.5mm jack instead. You may find it works well enough.

 

A concurrent post has been automatically merged from this point on.

 

Oh - by the way, many laptops simply don't have a 'line in' - you may find on closer checking of the spec that it is a mic input. Some do, though.

[paulears]

I read it as though he has an unbalanced mixer, and an unbalanced laptop, and he's using the DI to isolate the laptop from the mixer via the transformer. I do this all the time to get rid of the awful PSU noise my Dell laptop suffers from, going the other way - into, rather than out of, the PA.

 

I guess the obvious thing would be to try the laptop direct, close to the mixer. He'd still need the red/blue short to make it come up on both channels - but it would be a another potential solution. If the short length works, then add the long cable?

[Dave SA]

If he has an unbalanced mixer he'd want as short as possible an unbalanced jack lead. Not 30m!

[tinnitus_man]

Hi IA76

 

The DIB-100 DI box is passive - this is a transformer type isolator - it is unbalanced in and balanced out. If you short out any two pins you aren't going to get an output. If you go in unbalanced you can come out balanced.

 

Think of it this way (This is the easiest way I could think of explaining this I'm sure many of you could do better!!)- it's a transformer with Ground HOT and COLD connections - This is found on the output side. The transformer converts the audio signal into a magnet field and back again so when you short out pins 1 & 3 on the output in the XLR you are shorting out Cold down to Ground. If you short Cold to ground or Hot to ground you will stop any magnetic field developing. Same again if you short out Hot and Cold - no signal.

 

(Going on the specifications of the DI box and the mixer which I found on the net) Your mixer is an unbalanced output your DI box is unbalanced in and balanced out.

 

The output of the DI box is balanced Pin 2 Hot, Pin 3 Cold, Pin 1 ground - On XLR. You have shorted out pin 3 and 1 this is Cold to Ground - hence no signal.

 

I can see why use a DI box as there is such a long distance between mixer and laptop. The laptop can't have balanced input so to be honest there's no point in using the DI box. The output of the DI box really should be going into a balanced input, like a balanced input on a mixer. Also the Di has high input impedance 50K and lower output 600 ohms a ratio of 10 to 1. All the signal levels you are using are line level not mic level!

 

A DI box is meant to go in between the signal output of guitar and the guitar amplifier hence the link through jack! you then get a line level output to go into a mixer. The signal goes from low level signal up to a line level so there is less noise to signal ratio.

 

I think the easiest way of doing this is to remove the Di box. I know this may cause noise hum etc but you will get a signal to your laptop. If you want to do this the right way then I'm afraid you are going to have to spend a bit of money Perhaps buy a mixer with a balanced output and perhaps a sound card that has balanced inputs? There are a few ways of doing this - what do you say readers? :)

 

Hope I have given you an insight into the problem and hope you work it out.

 

Stuart

[TomHoward]

Just for future reference with your minijacks, personally I don't try soldering minijacks any more - they're so fiddly they're rarely worth the effort unless you have to. You can buy a minijack-minijack lead, or a minijack-phono lead and just cut the unwanted end off.

[paulears]

Forgive me - but it is VERY common practice to connect pins 1 and 3 from balanced kits to deliver an unbalanced output. As I'm sitting here - I have one of these exact DI boxes, although a different brand - but the same product. It is used to isolate a rather tricky bit of audio kit and feed the output to an input on another device. There is a tiny drop in level when unbalancing in this way - but to say doing this produces no output is tosh. A perfectly straightforward way of doing it. Indeed - the very same wiring is applied to XLR to unbalanced jack cables supplied with cheap mics.

 

A DI box is meant to go in between the signal output of guitar and the guitar amplifier hence the link through jack! you then get a line level output to go into a mixer. The signal goes from low level signal up to a line level so there is less noise to signal ratio.

What?

 

A DI box is designed to take a line (or guitar) level signal and produce a balanced output at MICROPHONE level to go into a piece of kit expecting mic level. The loop through output as said goes to the amp if you are using it on a guitar, or keyboard etc. In essence, all a DI does is 'sniff' the signal passing through and then allowing some to emerge, which the mixer treats as if it was a mic!

 

You've got the wrong end of the stick - and your understanding of how DI boxes work is a bit flawed - sorry!

[Mixermend]

There are often problems interfacing laptops and other computers to audio systems - in this instance I think that you need to CONFIRM that you are actually trying to feed the signal into a stereo line input.

 

Some TRS mini jack (3.5mm) inputs are designed for use with electret microphones, so the jack socket has a polarising voltage present for the microphone - this could cause problems when feeding from a transformer output.......

[tinnitus_man]

Forgive me - but it is VERY common practice to connect pins 1 and 3 from balanced kits to deliver an unbalanced output. As I'm sitting here - I have one of these exact DI boxes, although a different brand - but the same product. It is used to isolate a rather tricky bit of audio kit and feed the output to an input on another device. There is a tiny drop in level when unbalancing in this way - but to say doing this produces no output is tosh. A perfectly straightforward way of doing it. Indeed - the very same wiring is applied to XLR to unbalanced jack cables supplied with cheap mics.

 

A DI box is meant to go in between the signal output of guitar and the guitar amplifier hence the link through jack! you then get a line level output to go into a mixer. The signal goes from low level signal up to a line level so there is less noise to signal ratio.

What?

 

A DI box is designed to take a line (or guitar) level signal and produce a balanced output at MICROPHONE level to go into a piece of kit expecting mic level. The loop through output as said goes to the amp if you are using it on a guitar, or keyboard etc. In essence, all a DI does is 'sniff' the signal passing through and then allowing some to emerge, which the mixer treats as if it was a mic!

 

You've got the wrong end of the stick - and your understanding of how DI boxes work is a bit flawed - sorry!

 

I know I'm right about the output of the DI box.

 

If you set the box at 0dB on the attenuator then what ever went in would come out 10 times higher that's what I am getting at.

 

True you would go in on a microphone input but the output could be line level going into it - so the gain would be set low on the channel. Signal to noise ratio as I say. there are mixers with mic/line switches on out there as well!

 

Having read the user manual on the DI box it would appear you can connect the output of the speaker to it's input!! So it can be anything from microphone level input to a rather high voltage input! so not just a guitar as I said, again with the aid of the attenuator anything is nearly possible.

 

I still think the DI box between a mixer output Unbalanced to a laptop input is not really the right way around this after all both are unbalanced and the point of this Di box as said by IA76 is because the lead is so long 30 meters hence stopping the hum over the distance. I suppose there is also the DC element as well between laptop and mixer output.

 

I just wonder now if IA76 has sorted the problem. Connect the XLR - ground pin 1 signal pin 2 don't connect pins 1 and 3 together. You will get signal I'm sure.

[Andrew C]

The wise man when in a hole stops digging.