Running Long Headphone Lines

[Siegfried Meier]

Hey guys,

I have a scenario here where I want to use the headphone out of our Dangerous Monitor ST to send out to the tracking floor, so I can control the headphone level.  I have a headphone mixer out there, but let's ignore that for a sec since I want control in here (and also, the Dangerous sounds way better).

It's around 70-80' of cabling, so simply running the signal out there on one of the balanced lines is riddled with hum and buzz by the time it gets there - it sounds great, but noisy when idle.  Is there a device that I'm not aware of that will keep my line balanced all the way out there, and then just turn it into a regular stereo / headphone line that last couple of feet?  I tried using a radial DI in reverse, level was too quiet.  I was thinking of some sort of other balancing transformer or electronically balanced device, but that would make it mono really - unless I run it out in 2 separate balanced lines I guess.  Just wondering if there's a ready made solution for this out there.

Thanks!
Sig

 

[Siegfried Meier]

A pair of Radial SGI's would do it - running on 2 balanced lines, but that could get expensive...anyone have thoughts on a simpler, cheaper way?

 

[PRR]

How can you play electric guitar in a room that corrupts headphone lines??

I used to run 3-wire stereo at hot headphone level ALL over the concert hall, often in unsheilded wire.

I wonder if you have some other issue like ground loops.

Yes, we should run TWO lines for stereo, it's two signals. There's other ways (multiplexing, phantom circuits, way-huge signal levels) but two balanced lines is the for-sure method.

Balance and unbalance with transformers or those new chips. A DI normally gives a heavy voltage reduction (guitar voltage is higher than mike voltage; and both are lower than good line levels).

 

[0dbfs]

I would send it our line level and use a small HP amp out in the room.

Cheers!
-jb

 

[JohnRoberts]

To second what PRR is saying I suspect the ground is getting contaminated. You should be able to send cans that far without problem.

JR

 

[drknob]

Yup. Something else is going on. I used to run hundreds of feet of unshielded headphone/speaker cable for large orchestra setups in a commercial studio - never a problem. Do yourself a favour though - if you're using low impedance headphones (<50 ohms) use heavier gauge wire. The resistance of 100' of  everyday mic cable is significant when compared to iPod style phones.