John Sayers' Recording Studio Design Forum Archive

i would like to run guitar and microphone cables inside a duct from a room to another where i would put guitar amps and mics to be able to monitor and recording while standing in the control room. The audio cables passing in the duct would run together with the cables from the house electrical system:
- could be any interference problems between the electrical system cables and audio's ones?
- should i make the guitar to amp (in the other room) cable balanced? still don't know how cables are going to be long but 30 feet easy
- i would build a xlr patchbay, what do you think about plugging the guitar to xlr?
- any problems with the phantom power mics through a patchbay?
thank you all!
Omar

You don't EVER want to run signal (guitar, mic) in the same conduit with power - at the least, they should be 1/3 meter away if they're in GROUNDED METALLIC conduit, and further if it's plastic. This is for parallel runs - when crossing, do so at 90 degrees.

Balancing can be done with a pair of line transformers, but this will usually lower the high frequency response - maybe an active DI box - there are a few different ones available, not sure about in Italy. 30 feet for an unbalanced guitar signal may get you noise, depending on where your power is run and the local radio/TV station interference.

Guitar to XLR would be fine if it's balanced, maybe even if not.

Phantom power and patch bays are NOT usually a good combination - definitely NOT for standard 6mm phone TRS plugs, usually not for "bantam" TT plugs, but you can use an XLR jack plate. The problem with the others is that they will short out the phantom power to ground while plugging/unplugging... Steve

Forgot to post this link for more wiring info -

http://www.rane.com/note110.html

hi Steve,
thank you for your reply!
- for the guitar signal i 'm going to use the Little Labs Signal Transmission Device (STD) from www.mercenary.com
- yes, the TRS would short because when plugged/unplugged the jack tip would come in contact with the sleeve and the ring, right?

thank you for the link. I'm trying to understand ground loops now.

That's right - this situation has blown more than a few phantom supplies.
You're welcome... Steve