I want to run a line to my back bedroom from my studio, so I can test the mix in another room. I am thinking a balanced line from the balanced +4 output of my Behringer Ultralink MX882, into a couple of Studiospares Red 502 balanced/unbalanced converters, and then unbalanced into the phonos on the back of the bedroom Denon PMA 715R hifi power amp. The cable run would be 27metres, and I intend to get Europa ultimate, Studiospares 548900. Is this all correct ?

27 Meters is easy, even without balancing, espically at line level signals. As for cable I ahve used this previously http://www.thomann.de/gb/cordial_cmk_422_zwillingskabel.htm which if you are running two balanced stereo lines may be a better idea. However you should be able to get away with running it unbalanced but you would then loose the advantages, such as less chance of ground loops/interference etc.
Balanced cables will easily run over 100m even at mic levels so cable length will not be problematic.

This picture http://www.studiospares.com/cable-balanced-/europa-ultimate-black-mic-cabl e-per-metre/invt/548900/&temp=enlarged&layout=empty
Of that cable seems to show two parallel core individually screened with a black carbon shield?

If that is the case then it will not perform at all well as a balanced cable.

Dave.

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I want to run a line to my back bedroom from my studio, so I can test the mix in another room. I am thinking a balanced line from the balanced +4 output of my Behringer Ultralink MX882, into a couple of Studiospares Red 502 balanced/unbalanced converters, and then unbalanced into the phonos on the back of the bedroom Denon PMA 715R hifi power amp.

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Fair enough. In some cases it is possible to run a balanced output directly into an unblanced input without risking ground loops, but the behringer requires piins 1 and 3 in the output XLR to be linked for unbalanced operation, so ground loops would be a potential problem...

...In which case transformer isolation and format conversion is the way to go. The ART Cleanbox 2 would be a more cost effective solution than a pair of Red 502s, though.

Quote:

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The cable run would be 27metres, and I intend to get Europa ultimate, Studiospares 548900. Is this all correct ?

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The distance is no problem at all. That Europa cable would do, but this 'stereo' cable would be more cost-effective.

http://www.studiospares.com/cable-balanced-/mic-cable-stereo-per-metre/inv t/548120/

Actually, for this kind of thing I often use a single run of 'star-quad' and use the opposite pairs for the two channels. it works very well and is only one cable to pull through...

http://www.studiospares.com/cable-balanced-/quadfle-x-cable-mtr/invt/54054 1/?htxt=NfoJvFqh%2FOXeZTLLWQm1nTD3wxukfCcTB4BXzUZ002Np9oT5ydthJvTjqgNFl4P2T2%2FjXjUTUdXT%0 AFRlCvr6NpA%3D%3D

...but the studiospares stereo cable would be more cost-effective.

Bear in mind that the B mixer is expecting to output nominal +4dBu levels and the hifi amp is probably expecting -10dBV inputs... which are 12dB quieter! The Cleanbox2 uses 1:1 transformers, so there is no level shift. I'm not sure if the Red 502 provides the level adjustment or not -- the website doesn't seem to say.

Obviously, you can easily turn down the master level at the B mixer when auditioning inthe bedroom, or you could build a couple of simple in-line attenuators for the unbalanced connection to the hifi with just two resistors soldered into the jack plugs.

hugh

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Technical Editor, Sound On Sound

Ah! Now that..
http://www.studiospares.com/cable-balanced-/mic-cable-stereo-per-metre/inv t/548120/&temp=enlarged&layout=empty
Looks right! Twisted pairs.

Might I also add that IMHO 27mtr balanced is nothing. UN balanced is pretty dodgy.
Dave.

Edited by ef37a (27/02/12 09:51 AM)

Thanks all of you for your help, much appreciated...

Firstly, thanks for the tip about the cheaper art box, I'll get that instead.

Secondly, about the cable, the 27 metre journey to the back bedroom includes passing through an old cupboard, and a kitchen, which doubles as a live room with temporary screens when required. There is a studiospares multicore that connects a wall box in the live room/kitchen to the Mac interface, and I drilled a few holes and plastered in a bit of piping to allow passage of the multicore, with a diameter of about 35mm. So I am intending to use the existing piping between the rooms to get to the back bedroom. I did a little dummy run, and decided that it would be much easier to have two single cables (with an XLR on the end) to thread though the piping (half of which is already taken up by the multicore) than a stereo cable with two XLRs, which wouldn't fit, unless of course the cable be easily split for about 50cm to allow individual threading through the wall pipes. Of course, I could perhaps thread them through the piping without the plugs on, and the solder them on myself afterwards. But this would mean buying a soldering iron and overcoming my fear of soldering...Since I started home recording 20yrs ago I have always used ready made, or had them done for me by a cheap friendly local electrician, who doesn't do house calls !

(Sound of pennies dropping loudly)

Hold that last posting !!

I have just checked the Art manual, and it shows jacks not XLRs...

So I have just checked my piping, and I think I can probably do it as long as I can safely split the first 50mm of the stereo cable ?

http://cpc.farnell.com/jsp/level5/module.jsp?moduleId=cpc/472924.xml
I am pretty sure (but can't find it!) that these wallplates are screw connection.

Even if not do not try to solder the cables in situ. Put the XLR sockets on whatever plate you decide (you can get 8 easily on a standard "13amp" outlet plate) upon and wire them in comfort on the bench, aka kitchen table. Then use 2amp electricians "chocbloc" screw connector strip to connect to the cables.

My whole bungalow is festooned in such wiring except mine is CAT 5e FTP cable because I "rescued" about 1/2 click of it from the firms skip!

And do not forget to leave a strong chord in the tubing because you WILL need to pull more wires through one day!

Dave.