Unbalanced line level to Balanced Line input

[gilkinted]

I want to connect unbalanced line level audio signal (laptop, mp3 player etc.,) to a balanced line input (female XLR stereo pair). The balanced input is on an ART MX225 zone distribution mixer. The XLR inputs have input level control BUT do I need to go via a mixer pre-amp stage first? Length of audio cable to dis mixer is no more than 6 metres. Convention dictates that the XLR input should 'see' a balanced signal but is that extra 'mixer' necessary do we think?

 

Allan

[Brian]

One of the best 'how do I connect this to that' guides.

[durian]

the chances are the XLR inputs could be at +4db and the laptop is likely to be nearer -10db so there will be a level mis match but it should work fine. I do this on a daily basis with nothing inbetween the laptop and the desk.

 

you might find, depending on the laptop and its psu, that you will get noise, in which case I would suggest a stereo DI box, which would also bump the impedance to 600 ohms for an XLR input. if the laptop is noisy try it on battery to eliminate the noise.

 

http://www.blitzfamily.eclipse.co.uk/paulblitz.co.uk/tech_tips/techtip/art6.htm

[gilkinted]

Wow! Thanks for that - required reading - even if you thought you knew (and had forgotten) it all! The answer is in there somewhere..... :-)

 

Allan

[Oldradiohand]

This sort of thing?

http://www.ebay.co.uk/itm/Alice-Matchpack-Pro-Interface-Unit-/130688573396?pt=Midi_Controllers&hash=item1e6da55fd4#ht_1312wt_1173

I think Canford still do something similar....

[durian]

ALICE :)

 

I still use an Alice stereo phono pre amp .... lovely.....

 

 

OH yeah take me back to my radio days and Alices' boxes everywhere :)

[gilkinted]

Yes - that Alice is cool - and a neater solution than a mini-mixer if you don't need one. Might go with that idea - thanks

 

Allan

[Simon Lewis]

I've not checked it out, but this cable seems to carry out impedance balancing - in the cable connection itself.

 

 

[Lamplighter]

I've not checked it out, but this cable seems to carry out impedance balancing - in the cable connection itself.

Its not difficult, two resistors and a capacitor will do the trick, only one resistor if you know the output impedance of the unbalanced source. Ive used this a a workaround with the auxes on cheaper mixers since the mists of time.

Brian

[ramdram]

Have you considered the usb out (of lappy) to XLR devices?

 

For example (as it in built in Australia):

 

http://www.arx.com.au/International/audibox_usb_di.htm

 

We see an increasing number of tours using lappies with fairly trendy external sound cards to cobble into our amps. This is, obviously, a more expensive solution.

 

(Slightly OT, but on the lappy to sound desk issue we see on occasion usb out to usb in. We have an A&H Zed 436 and seems to work quite satis'.

[paulears]

The sound on sound one is just wired XLR 2 to tip, XLR 3 to sleeve - so the differential input of the XLR socket is used, not the ground - which at the XLR end is not connected. Hugh Robjohns has been promoting this hum curing wiring for years - works pretty well.