Multi-core cable help please.

[jb63]

I put together an "on-the-cheap" IEM rig awhile back consisting of a 4 channel mixer and a SansAmp preamp pedal. I'm currently using an instrument cable and a headphone extension cable taped together. I'd like to have one cable that cable that will carry the instrument signal and the headphone signal. Something like this:
Invalid Link Removed

 

[Jimbob Jones]

I've done this before, you need cable with three cores + earth.

You'll struggle to find that, so you'll most likely have to settle with four cores + earth. Here's how I wired mine:

red: bass signal

blue: bass earth (ground)

white: headphone left

green: headphone right

shield (jacket): headphone earth (ground)

Make sure that the two earths are shorted together, or you may get noise in one or both cables

EDIT: the cable is called 'starquad' and is designed for pro audio applications where you use all four cores for one XLR (or TRS) lead, but it's also very useful for getting more than one signal down one cable!

 

[jb63]

Thanks for the reply Jim. Wouldn't the instrument lead have to be shielded from the headphone leads to eliminate crosstalk?

The cable in the pic would called "four strand shielded" right?

 

[Hellbastard]

I don't know if you can buy it in the U.S, but here in Europe we have a company called Cordial, and they make a twin line microphone cable that would be perfect for your application. Cordial CMK422.

 

[Jimbob Jones]

The cable's often sold as 'starquad' or sometimes 'quadflex'.

I tried isolating the two earths and just ended up with noise. Once I shorted them it went away, but YMMV!

 

[jb63]

Thanks for the help!

 

[WayneP]

You might try some Mogami so-called “snake cable.” You typically see it in 16, 24 channels etc., but Mogami makes it all the way down to two channels, and each channel is independently shielded. Tobias Club sells the two-channel for about a buck fifty/ft. Here’s the technical description from Mogami’s website.

The only caveat is that the cable’s primary protection comes from its thick outer jacket. Once you strip that back, the jacket on the individual channel cables is very thin and won’t take a lot of abuse. So it would be a good idea to strain-relief the cable at both ends at all times.

Regards,
Wayne A. Pflughaupt


Administrator, Pedulla Club #45
Administrator, Big Cabs Club #23
Tobias Club
Pedulla Club #45

 

[Never_grew_up]

You might try some Mogami so-called “snake cable.” You typically see it in 16, 24 channels etc., but Mogami makes it all the way down to two channels, and each channel is independently shielded. Tobias Club sells the two-channel for about a buck fifty/ft. Here’s the technical description from Mogami’s website.

The only caveat is that the cable’s primary protection comes from its thick outer jacket. Once you strip that back, the jacket on the individual channel cables is very thin and won’t take a lot of abuse. So it would be a good idea to strain-relief the cable at both ends at all times.

Regards,
Wayne A. Pflughaupt


Administrator, Pedulla Club #45
Administrator, Big Cabs Club #23
Tobias Club
Pedulla Club #45

At each end where you split the cables out use heatshrink tubing to replace the outer jacket that got stripped away, and a short 2-3" long but slightly larger diameter piece right where the 2 lines separate for strain relief.

 

[jb63]

You might try some Mogami so-called “snake cable.” You typically see it in 16, 24 channels etc., but Mogami makes it all the way down to two channels, and each channel is independently shielded. Tobias Club sells the two-channel for about a buck fifty/ft. Here’s the technical description from Mogami’s website.

The only caveat is that the cable’s primary protection comes from its thick outer jacket. Once you strip that back, the jacket on the individual channel cables is very thin and won’t take a lot of abuse. So it would be a good idea to strain-relief the cable at both ends at all times.

Regards,
Wayne A. Pflughaupt


Administrator, Pedulla Club #45
Administrator, Big Cabs Club #23
Tobias Club
Pedulla Club #45

Thanks Wayne, this is what I'm looking for!

 

[F-Clef-Jef]

I use Invalid Link Removed, works very well. I tried the star cable route, but the wire gauge is too thin if you are using a passive pick-up. The signal got pretty thin/weak after only 12 - 15 foot cable run.
The Mogami cable is basically just 2 mic cables bonded together, sort of like regular old lamp cord. It's much easier to seperate the two cables at the ends this way also.