+48V - how far?

[AllyMusicGirl]

Does anyone know how far you can run a mic cable and still pump +48V throught it?

 

I gotta run a cable about 30 meters. (100 feet)

 

Also I'm running this mic cable up in a tiled ceiling in close proximity to fluorescent lights and HVAC duct work - any potential issues?

 

 

Cheers!

[simonphoenix]

Try to stay away from those damned lights as far as you can. Consider extra insulated cables, if you haven't bought it already.

 

When you do have the cable you can always run 48volts down it and check the other end with a multimeter, there would most likely be a drop, but I don't know how much. You do need to find out that whether your mics can run safely on the overall voltage it does output.

[Jope]

It depends on the current consumption and the acceptable voltage range of the mic. My perception 200 takes 2mA and the operating voltage is 48V +-4V. The voltage drop of 4V at 2mA means the cable could have a resistence of 2k, which it never has within 30m, no matter how thin it is; so this is hardly a problem. But the electromagnetic noise produced by electronic lamp starters and dimmers can be real trouble, as simonphoenix wrote. You need proper shielding and as much distance to the power cables and devices as possible.

[fader8]

Ally,

Even at 500 feet you'll be OK. Always use good cabling and connectors though.

[simonphoenix]

I forgot to mention if you have to cross power cables, do it at 90 degrees to minimise the impact.

[AllyMusicGirl]

Thank you all!

[simonphoenix]

Always a pleasure.

 

Hopefully we have been of some help.